#linuxcnc Logs
Dec 18 2017
#linuxcnc Calendar
12:03 AM `Wolf: mostly almost getting stuff done here...
12:05 AM `Wolf: just tossed a indicator on one of the TTS holders in the jet mill, run out on the outside of the collet holder body, 0.0003” …
12:06 AM `Wolf: random 3/8” steel pin reading 0.0025” runout in the er-16 collet
12:12 AM gloops: https://www.ebay.co.uk/itm/Woodworking-Dust-Extractor/302561645550? always too far away
12:27 AM `Wolf: meh, I think I can work with this mill… just checked the tram
12:28 AM `Wolf: 0.001” over 14” span is kinda ok right? =)
12:29 AM XXCoder: no idea lol
12:29 AM XXCoder: depends a lot on what you need
12:29 AM gloops: yes that will do i suppose
12:30 AM `Wolf: hell that could be error in the pin that I have the indicator attached to.. (or the other way and its really not trammed lol)
12:34 AM longbow: good morning! :)
12:35 AM longbow: I'm looking for a motherboard (mini-ITX) for linuxcnc with mesa 6i25 cards.
12:35 AM longbow: Is this ASUS with Celeron good?: ASUS N3150I-C CELERON MINI-ITX LGA1151
12:43 AM longbow: Is this more appropriate: MXGTH0-A0UAYZ ? - Asrock Intel J1900
12:45 AM MrHindsight: just about any board with PCIe will work
12:46 AM MrHindsight: longbow: ^^
12:47 AM longbow: even with an integrated Celeron? :)
12:49 AM MrHindsight: why not?
12:49 AM MrHindsight: you're not planning any software stepping
12:54 AM IchGucksLive: morning
12:55 AM IchGucksLive: longbow: still on
12:58 AM longbow: still on
12:58 AM longbow: no, I use servos
12:58 AM IchGucksLive: if you go mesa there is no hint to the pc
12:59 AM longbow: ok
12:59 AM IchGucksLive: the cards got there own mind
12:59 AM IchGucksLive: and dont rely on board power
12:59 AM IchGucksLive: i woudt go for the J1900
12:59 AM IchGucksLive: it is the better performence board
01:00 AM IchGucksLive: and alot here using this
01:00 AM longbow: better than ASUS N3150I-C?
01:03 AM IchGucksLive: i say yes as it has also more flexibility
01:04 AM IchGucksLive: but it up to you the asus is shure the newer one
01:04 AM longbow: Im deciding
01:04 AM longbow: is newer always better? :P
01:04 AM IchGucksLive: no
01:05 AM IchGucksLive: if you grap a new version you might be the first in trouble
01:07 AM longbow: hehe
01:12 AM gloops: he who dares wins!
01:15 AM Cromaglious: I'm running Atom 4 core .4Ghz mini ITX Mini-box.com cases, biggest problem is only 2GB RAM max...
01:15 AM Cromaglious: 1.4ghz
01:17 AM longbow: why you need more than 2GB??
01:19 AM gloops: you can never have enough RAM
01:19 AM longbow: but for running linuxcnc?
01:20 AM gloops: ive no idea what would be a minimum for linuxcnc, mine ran fine with 2
01:21 AM longbow: I also think that for linuxcnc you dont need more than 2gb. Also with 1gb should work
01:22 AM gloops: something you can easily monitor while linux is running, the scope to add more would always be preferable id think
01:23 AM `Wolf: need the extra ram to cover the overhead from firefox when your watching youtube while machining
01:24 AM gloops: these old XP era pcs run linuxcnc fine using parport, ive not used mesa yet so dont really know what extra requirements for processing power or memory
01:25 AM longbow: i have one linuxcnc system up and running with 3 mesa cards 6i25+7i77+7i64 wuth 2GB and works no problem
01:27 AM Contract_Pilot: Thinking one of these for the X axis home switch https://www.alliedelec.com/search/productview.aspx?SKU=70207613
01:28 AM Contract_Pilot: I am using 50.00 lenovo's hahaha
01:28 AM gloops: i can tell you something, half inch thick aluminium plate - 8 inch wide DOES bend - a friggin lot
01:29 AM gloops: i knew i should have gone for 20mm
01:30 AM longbow: which type of aluminium?
01:32 AM gloops: Grade: 6082 T6
01:33 AM gloops: its not bolted yet but if i put pressure on it i can see it moving
01:37 AM gloops: the plates are cupped by about 1mm, so much for the accuracy of aluminium components, box section steel is closer
01:38 AM Contract_Pilot: 1/2" aluminum will bend simply
01:39 AM gloops: i knew, its my own fault
01:39 AM Contract_Pilot: 7075 will not as easy it just cracks
01:40 AM gloops: just a question of by how much when cutting, and theres only one way to find out
01:43 AM archivist: add webs to stop bending
01:44 AM gloops: the back plate will be ok the linear bearings will brace it, its the front one
01:45 AM gloops: might be better mounting the rails on the front
01:45 AM Loetmichel: 7075 has a monstrous mininmal bend radius. that stuff is nearly as brittle as cast alu
01:46 AM gloops: as i understand, the bendiness banwidth accross various alloys is not great
01:46 AM gloops: a few percent
01:46 AM Loetmichel: i dont mean bendiness
01:47 AM Loetmichel: i mean minimum radius of bend before it cracks
01:47 AM gloops: thats like shear values, im more concerned with deflection
01:47 AM Loetmichel: even AlMg3 starts cracking if you have an 1/8" sheet and bend it to 1mm inner radius
01:48 AM Loetmichel: been there, seen that, looks like a sponge on the outside afterwards
01:48 AM Contract_Pilot: Ahhhh well back to trying to figure the woring from emmerson VFD to hitiachi WJ200 VFD
01:48 AM gloops: ive paid £50 for a mis-shaped sheet of melted down pop cans !
01:49 AM Loetmichel: nope. if it were remeltet pop cans without refinement you would look at a LOT more stresses in the material
01:49 AM Loetmichel: i have seen 1' pieces of 8mm thick sheet alu that bends 15mmU!
01:50 AM Loetmichel: 15mm(!) whnen milled on one side
01:50 AM gloops: the ones i made myself do not bend
01:50 AM gloops: 6 inch wide
01:50 AM Loetmichel: if you want less "bendiness" go to cast aluminium plates
01:51 AM Loetmichel: and stress relieve them before milling
01:51 AM gloops: i tried, well anyway i can make some more, i bought these to save time
01:53 AM gloops: i begin to wonder how accurate these ally extrusion machines are after all
01:56 AM Deejay: moin
01:57 AM Loetmichel: gloops: not that much
01:57 AM Loetmichel: all that extrusion stuff is "banana"
01:57 AM gloops: i can believe it
01:57 AM Loetmichel: never seen more than 1' even remotely straight
01:58 AM archivist: the start of an extrusion run is specially bad
01:58 AM Loetmichel: you can buy some "straightened" stuff here. that went thru a press to straighten the worst bends out after extrusion and cooldown.
01:58 AM gloops: i might do a photo comparison of this, the cupped shiny ally plate with a straight edge accross, and the flat mild steel plate
01:59 AM gloops: see what the shiny ally machine owners on facebook think
01:59 AM Loetmichel: downside of that stuff is that it introduces stress into the material...
01:59 AM Loetmichel: when you cut the surface on one side it bends worse than the normal extrusion stuff
02:00 AM Loetmichel: hmmm
02:00 AM Loetmichel: cold rolled steel does the same trick
02:00 AM gloops: i bet hiwin square rails would struggle on these plates
02:00 AM gloops: espeically if you got the cupping opposing
02:01 AM archivist: hiwin etc will need pulling straight
02:01 AM Loetmichel: aluminium is weak enough that the usual router bed constructions simply bend into shape ;)
02:02 AM Loetmichel: or the gantry follows the inward bend of the y axis and simply shrinks in the middle
02:02 AM gloops: i watch some vids comparing rails, hiwin is very unforgiving, couple of mm out you got problems
02:02 AM Loetmichel: ALL ball bearing linear rails are unforgiving
02:02 AM archivist: couple mm is a mile in good machine making terms
02:03 AM gloops: yes a couple of mm is a mile, and thats what these plates would give without any preparation
02:03 AM Loetmichel: you dont notice it on "flying" rails or SBR because they have enough "give" in them that they can cope
02:03 AM gloops: the round rails can pivot so you got plenty of movement in that direction
02:04 AM gloops: the rollon type rails are designed for poor alignment
02:04 AM gloops: for like 3rd world applications
02:05 AM Loetmichel: when i bolted down the SBRS on my 6040 to the desk i had to straighten them a good 3mm to get the gantry move in a straight line and dont do "bows"
02:05 AM gloops: my sbrs are bent 10mm
02:05 AM gloops: which im putting down to transit, hopefully the screws are not - they dont seem to be
02:06 AM Loetmichel: http://www.cyrom.org/palbum/main.php?g2_itemId=14139
02:06 AM Loetmichel: http://www.cyrom.org/palbum/main.php?g2_itemId=14133&g2_imageViewsIndex=1
02:07 AM Loetmichel: there you can see how i bolted tjem down
02:08 AM gloops: i started with a bolt at each end, then clamped the middle and got a bolt in
02:08 AM Loetmichel: same
02:54 AM Contract_Pilot: http://www.stevenrhine.com/wp-content/uploads/2017/12/VFD-Terminals-Side-By-Side.jpg
02:55 AM Contract_Pilot: Not sure i am going to get any spindle work done shoot.... hoping to get it done by now!
02:55 AM Contract_Pilot: Maybe in a week or 2
02:55 AM gloops: amazing how quick time slips by when wanting to finish something
03:00 AM archivist: gloops preston is not that far !
03:00 AM gloops: preston is near liverpool, miles away
03:00 AM archivist: only miles
03:00 AM archivist: I got a car from their on ebay
03:00 AM gloops: cant remember what it was now
03:00 AM gloops: not so bad for a car, not worth going for a £30 item though
03:01 AM archivist: sometimes when collecting you get offered extras, so even the cheap stuff turns out good
03:02 AM gloops: https://www.ebay.co.uk/itm/Raglan-Little-John-Lathe/263387374119?
03:02 AM gloops: that looks ok
03:02 AM gloops: probably go for more though
03:02 AM gloops: would have been if it was gearbox model
03:25 AM gloops: big rotary axis https://www.youtube.com/watch?v=XlNDQ2PVPpI
03:29 AM gloops: 120mm high velocity gun, the shells didnt need explosives, the velocity alone would penetrate any tank and come out the other side, 98% accurate at 3km
03:51 AM Contract_Pilot: Yea, time go quick... but the VFD is gonna take a bit longer than expected.
04:32 AM jthornton: morning
04:49 AM archivist: gloops, I blame you for me getting doughnuts in morrisons this morning!
04:52 AM gloops: its ok, so long as you get a packet of rennies with them lol
04:52 AM archivist: I have gust that does not need rennies!
05:14 AM Contract_Pilot: ICSPCLK
05:14 AM Contract_Pilot: ICSPDAT
05:14 AM Contract_Pilot: MCLR/VPP
05:14 AM Contract_Pilot: •VDD
05:14 AM Contract_Pilot: •VSS
05:15 AM XXCoder: decent paste there
05:28 AM Contract_Pilot: yea, maping pins on this bob
05:28 AM Contract_Pilot: that headder goes to the ISP
06:08 AM Tom_L: 28F
06:09 AM jthornton: 45f
06:09 AM Tom_L: it's coming
06:11 AM jthornton: not for a week here
06:15 AM XXCoder: snow wont be here at all
06:15 AM XXCoder: in least it seems
06:21 AM phipli: hum. much to do. what to do first...
06:21 AM phipli: probably make more tea
06:21 AM phipli: to drink while I consider what I should be doing.
06:21 AM jthornton: morning
06:21 AM phipli: morning
06:21 AM phipli: weather is good
06:22 AM phipli: I have no excuse not to make an upgraded chicken drinker and/or automatic door
06:22 AM phipli: first leave from work in months
06:22 AM phipli: haven't managed to take all of my leave this year
06:22 AM jthornton: the pullets are checking out the roll out nest box
06:23 AM phipli: exploring?
06:23 AM phipli: our white chicken has got so big that her tail is grubby from dragging on the perches
06:23 AM phipli: she's HUGE
06:23 AM jthornton: yes
06:23 AM XXCoder: thats issue with some breed of chickens
06:23 AM XXCoder: they cant breed
06:24 AM phipli: she's a white sussex
06:24 AM XXCoder: theres one guy thats preserving bunch of now hard to find chicken lines
06:24 AM jthornton: they will be 18 weeks old wednesday
06:24 AM XXCoder: jthornton: why not grab some of those
06:24 AM phipli: XXCoder, if I haven't told you before - interesting bread, it is at least most of 2000 years old
06:25 AM phipli: been here (UK) since the Romans were
06:25 AM phipli: dual purpose bird
06:25 AM XXCoder: nice
06:30 AM jthornton: which breed is that?
06:30 AM phipli: Light / white sussex
06:30 AM jthornton: working on getting the rpi to send me a status email at door open/close events when I'm not here
06:31 AM phipli: I have some instructions for that somewhere...
06:31 AM jthornton: cool
06:32 AM jthornton: http://stackabuse.com/how-to-send-emails-with-gmail-using-python/
06:34 AM xDR1TeK: hi people, how does linuxcnc interface with stepper motors and sensors? only LPT port?\
06:34 AM jthornton: many options at mesaus.com
06:34 AM xDR1TeK: i have been doing some reading, still brand new in this
06:39 AM phipli: jthornton, yeah - due to computer moves I can't find the instructions I was looking for :)
06:39 AM phipli: but it looks like you have something
06:42 AM jthornton: yea after fixing his syntax error it works
06:43 AM jthornton: well sorta works subject and from was wrong
06:51 AM gloops: aluminium plates.. http://picpaste.com/plates_002-eNPQf3D6.JPG
06:52 AM XXCoder: nice and bent
06:54 AM gloops: bent and bendy
06:55 AM gloops: im not sure, if you mount them with the cupping the same way they might be ok
06:56 AM jthornton: I see that a lot with 6061 but never with MIC6
06:56 AM gloops: yeah the mic is ground so they tell me
06:58 AM jthornton: it's also a cast aluminum so no stresses from rolling
07:00 AM jthornton: hmm still no subject or from
07:54 AM * phipli grumbles
07:55 AM phipli: who puts a 1/8th NPT thread on something and sells it in the UK?
07:55 AM phipli: short term bodge of running a 10mm die over it (it is plastic) made a surprisingly good job of it though
07:56 AM phipli: jthornton, I'll have a look through my old programs
07:56 AM phipli: I wrote something that sent emails with subjects / from etc once...
07:57 AM archivist: phipli, I just had that problem too!
07:57 AM phipli: not just me then :)
07:58 AM archivist: I got a npt to bsp adapter, then fkkkk the adapter is taper and the pressure sensor is parallel npt
07:58 AM phipli: thankfully I didn't spend too long being confused because my metric thread gauge had 27 tpi and 28 tpi on it, as well as a 1/8th npt die
07:59 AM archivist: I need a tap!
07:59 AM phipli: archivist, it has actually got quite difficult - a lot of suppliers don't bother writing p or t any more
07:59 AM phipli: how urgently? want to borrow one?
08:00 AM phipli: had to buy a load of BSP fittings for work - one supplier even "kindly" converted 3/8ths into metric and described the part as "9.5mm"
08:01 AM phipli: erm... no, 3/8 bsp is not equal to 9.5mm thread
08:01 AM archivist: no rush, it is a long term project you may be convinced to play at too, I want to measure leawood, get a digital steam diagram
08:02 AM archivist: output to a tablet screen
08:02 AM phipli: yeah - that is quite awesome
08:03 AM phipli: what kind of pressure would you be measuring (magnitude?)
08:04 AM archivist: max pressure safety valves blow at 40
08:04 AM phipli: psi?
08:04 AM JT-Shop: stupid quickbooks forces you to upgrade explorer
08:04 AM archivist: we dont do metric on that engine!
08:05 AM phipli: just checking :)
08:05 AM archivist: we wind up a lot of visitors :)
08:05 AM phipli: might have been bushels per cubit
08:06 AM archivist: I got one of the cheap automotive sensors off ebay -14.5 -30
08:08 AM JT-Shop: hmm one of the pullets is inside the nest box
08:08 AM archivist: may get this one for top of cylinder http://www.ebay.co.uk/itm/5V-0-1-2-MPa-Pressure-Transducer-Sensor-Oil-Fuel-Diesel-Gas-Water-Air-Sensor/282407738443
08:08 AM JT-Shop: I need a small poe ip camera in the egg collection box
08:14 AM IchGucksLive: hi
08:15 AM archivist: phipli, I think possibly the hard part is non intrusive engine movement sensing
08:32 AM phipli: laser distance measuring?
08:33 AM phipli: or measure the angle of the beam?
08:33 AM archivist: or hang an encoder with a magnet on the beam
08:34 AM Rab: archivist, parallel NPT = NPS. ;) https://www.usplastic.com/knowledgebase/article.aspx?contentkey=998
08:36 AM phipli: JT-Shop, or something that measures weight
08:37 AM Rab: NPT is common for plumbing here, I believe NPS is mostly used for electrical fittings. I had to find a tap for 3/4" NPS, it took a little searching.
08:37 AM archivist: accelerometer the thud of an egg drop
08:38 AM phipli: with the number of birds you have, you'll be tripping out there every half hour if you react to every egg :)
08:39 AM phipli: Rab : our stuff is almost all BSP
08:39 AM phipli: even though we've "gone metric"
08:39 AM archivist: except when the chinese sneek something in :)
08:39 AM phipli: exactly
08:40 AM * phipli glares at the drinker outlets
08:40 AM phipli: archivist, actually, the M10 die did a really good job of "converting" them
08:41 AM archivist: still have to end up with bsp
08:42 AM archivist: cheap fix https://www.ebay.co.uk/itm/Male-BSP-Female-NPT-BRASS-Reducing-Bush-BSP-to-American-Adapters-male-female/131225693084
08:42 AM Rab: I need to make some kind of motorized tapping machine for the huge 3/4" tap, actually. I made a holder for my drill press but runout is pretty bad.
08:42 AM Rab: Sweet, a search for 'linuxcnc thread milling' turns up example code for 3/4-16! http://wiki.linuxcnc.org/cgi-bin/wiki.pl?Example_G-Code_Programs
08:43 AM phipli: archivist, http://elephantandchicken.co.uk/projects/M10NPT.jpg
08:43 AM Rab: Presumably not tapered.
08:44 AM archivist: phipli The connection to the server was reset while the page was loading. problem inbetween somewhere
08:44 AM gloops: muscle power Rab
08:44 AM phipli: give it a second go
08:44 AM phipli: it isn't locally hosted
08:44 AM phipli: could drop the image size if it helps
08:45 AM archivist: nah I get a fixed set of urls not working
08:45 AM Rab: gloops, that's how I started--workpiece in drill press vise, crescent wrench on tap--but it gets old fast, and my runout isn't particularly good either.
08:45 AM archivist: weird problem, probably a proxy server in BT
08:46 AM phipli: strange
08:46 AM phipli: I've re-uploaded it smaller anyhow - I was just being lazy leaving it full size anyway.
08:47 AM archivist: since last wednesday morning
08:47 AM phipli: have you told them?
08:47 AM phipli: BT aren't the best at... listening
08:47 AM phipli: at all
08:48 AM archivist: really terrible company
08:49 AM phipli: the worst thing possible - a former nationalised industry converted into a for money monopoly
08:50 AM phipli: "it isn't our fault the competition didn't inherit an entire national infrastructure at bargain prices"
08:54 AM Rab: Is there a special name for single-point thread milling cutters? Is it just something people grind?
08:55 AM phipli: if you're cutting UNC you'll want a 60 degree angle on it
08:55 AM gregcnc: I've seen people take a tap and grind away all but one full tooth for thread milling
08:56 AM gregcnc: otherwise they are just single point thread mills
08:57 AM phipli: (to clarify, I mean the cut it makes needs to be a 60 degree 'V')
09:03 AM Rab: phipli, NPS, which also has a 60 degree angle. I guess it might be indistinguishable from UNC, unless the thread crest profile is different.
09:08 AM phipli: http://www2.mae.ufl.edu/designlab/Lab%20Resources/Types_of_threads.pdf
09:12 AM JT-Shop: hmm maybe put a through beam in the nest box to count eggs and alert me when one is laid
09:14 AM _methods: scale?
09:15 AM _methods: scale is probably overly complicated
09:15 AM _methods: what about a little arm that trips a switch when an egg comes into the box
09:16 AM jym: Train the chickens to BARK every time they lay an egg.
09:17 AM _methods: ^^
09:18 AM phipli: spring loaded flap that taps a microswitch when an egg rolls over it
09:19 AM phipli: jym : they do
09:19 AM phipli: it is called "the egg song"
09:19 AM phipli: they sing it loud, they sing it proud
09:20 AM phipli: https://www.youtube.com/watch?v=17wGTlGKJJ0
09:21 AM phipli: https://www.youtube.com/watch?v=_VO8CZ3EV2E
09:28 AM archivist: Rab, you can buy inserts for thread profile
09:38 AM phipli: JT-Shop, jthornton - which machine are you on?
09:50 AM IchGucksLive: Hi from a snow melting Germany
10:03 AM phipli: hey Ich
10:04 AM phipli: had much snow? we had ~60mm or so
10:04 AM phipli: last week
10:04 AM phipli: all gone now
10:29 AM roycroft: grrr
10:29 AM roycroft: i had to go out to the shop for a minute this morning before work and noticed that 3 of the 4 mounting holes in that second piece of acrylic had cracked overnight
10:30 AM phipli: thermal expansion / contraction?
10:30 AM roycroft: so now i have to remake that part as well, and those holes were not countersunk, so my experiment yesterday that indicated that the countersink was the likely cause was proven wrong
10:30 AM roycroft: it got down to 5 degrees in the shop last night
10:31 AM phipli: hum
10:31 AM roycroft: and i had the shop up to about 15 degrees when i was making the parts
10:31 AM archivist: roycroft, use caphead screws not counterskunks
10:31 AM roycroft: so not a huge temperature differenc
10:31 AM roycroft: i did on this part
10:31 AM roycroft: the other part needed to have flush fasteners
10:31 AM phipli: not sure how much acrylic changes size
10:31 AM roycroft: but i replaced that part with a piece of oak
10:31 AM archivist: a lot
10:32 AM phipli: worth putting some kind of rubber grommet in the holes?
10:32 AM phipli: to take up any movement / stress
10:33 AM phipli: how big is the sign (major dimension)?
10:33 AM phipli: 10 degrees change on a 3m sign would cause 2.25mm change in dimensions
10:33 AM phipli: that is quite a lot
10:33 AM phipli: http://www.pmma.dk/Acryl_Expansion.aspx?Lang=en-GB
10:34 AM roycroft: it's not a sign
10:34 AM roycroft: it's just a tiny collet holder
10:34 AM phipli: ah right - sorry, don't know where I got that from
10:34 AM roycroft: i'm using 6-32 screws, and drilled a #27 clearance hole (0.1440")
10:34 AM roycroft: that's a close clearance hole
10:34 AM roycroft: but the screws turn easily, so they don't seem to be "captured" by the acrylic
10:35 AM phipli: is it worth flame polishing the inside of the holes?
10:35 AM phipli: to remove stress raisers
10:35 AM roycroft: it might be worth just switching to polycarbonate at this point :)
10:35 AM phipli: true :)
10:35 AM phipli: or lead
10:35 AM roycroft: i chose acrylic because of its scratch-resistance
10:36 AM roycroft: and once the problem came up i wanted to try to figure out what was causing it
10:36 AM roycroft: but now i'm at a point where i don't care that much
10:36 AM phipli: which is the one that has bubbles in it if you over heat it?
10:36 AM roycroft: i've not had either do that
10:36 AM roycroft: but polycarbonate bends cold reasonably well, and if it's thick it doesn't take as much heat as acrylic to bend
10:37 AM roycroft: i suspect the real problem here is that it's just crappy acrylic
10:37 AM MarcelineVQ: speaking of which, did you want to try heating the acrylic before/during the drilling to see if that helps?
10:37 AM roycroft: it was a remnant, and almost certainly extruded, not cast
10:37 AM phipli: from the internet, I think it is polycarb that bubbles if you leave the heat on it for too long
10:38 AM roycroft: polycarbonate is much less brittle than acrylic
10:38 AM roycroft: hence its increased resistance to breakage
10:38 AM MarcelineVQ: it also costs an arm and a leg
10:38 AM phipli: tough not hard
10:38 AM roycroft: but it's also a lot softer than acrylic, and therefore more prone to scratching
10:39 AM roycroft: this is a tiny part - cost is not a factor
10:39 AM roycroft: it costs me way more in time to do the simple machining than the cost of the material
10:39 AM phipli: but time... :(
10:39 AM phipli: yeah
10:39 AM archivist: use metal
10:39 AM roycroft: and this is a shop project that does not have to be perfect
10:39 AM MarcelineVQ: not perfect? heck use a chunk of firewood hehe :>
10:39 AM roycroft: but shop projects are in part for debugging processes so that production projects work out well
10:40 AM gloops: wow train off the rails in washington
10:41 AM gloops: carriage fell off bridge onto freeway
10:41 AM MarcelineVQ: 'eye witness on sight report not being able to look away'
10:41 AM roycroft: i've worked with acrylic in the past without issues like this
10:41 AM roycroft: washington dc or the real washington?
10:41 AM gloops: dc i think
10:43 AM archivist: washington state on the bbc
10:43 AM phipli: "Washington state" "I-5 highway outside Seattle"
10:43 AM phipli: what archivist said
10:44 AM phipli: I was typing while looking at the other screen
10:44 AM phipli: urgh
10:44 AM MarcelineVQ: Wonder what happened, that sort of thing is awfully rare these days it seems to me
10:44 AM phipli: https://www.cnbc.com/2017/12/18/amtrak-train-derails-near-seattle-onto-the-i-5-freeway.html
10:44 AM phipli: some pictures
10:45 AM MarcelineVQ: oh a passenger train too?
10:45 AM phipli: yeah
10:45 AM phipli: a few crashes still seem to happen in the US
10:45 AM phipli: there have been a couple of others over the last year or so
10:45 AM MarcelineVQ: shouldn't have been ice buildup,. given the weather here lately
10:46 AM phipli: Germany, Spain, Italy have had a few over the last couple of years as well
10:46 AM phipli: France had one in the last week, but that was "road vehicle on crossing" which I don't tend to count
10:46 AM phipli: because it wasn't something going wrong on the railway
10:47 AM MarcelineVQ: it's come off an overpass bridge? strange strange
10:47 AM MarcelineVQ: strtange since it's a fairly straight track in that case I mean
10:48 AM phipli: rail defect?
10:48 AM MarcelineVQ: could be testle failure of some kind even
10:49 AM gloops: funny it coming off right over the road like that
10:49 AM MarcelineVQ: that's not actully the right word in this case, I can't think of the right one
10:49 AM roycroft: we had some new rules requiring mechanisms to auto-stop trains if the head into curves at higher than the speed limit (many of our recent train wrecks have been due to that exact cause)
10:49 AM MarcelineVQ: probably just bridge is correct
10:49 AM roycroft: but the trump administration decided those rules were too onerous to the railroads, and nixed them
10:50 AM phipli: we'd call it a railway bridge in the UK
10:50 AM phipli: viaducts are the long ones that keep the rails above the ground to avoid having to dip down into a valley or whatever
10:50 AM phipli: but that doesn't look like one.
10:50 AM roycroft: viaducts carry water :)
10:51 AM gloops: thats an aqueduct
10:51 AM MarcelineVQ: aquaducts carry water via ducts, doh ho ho
10:51 AM phipli: that is an aqueduct
10:51 AM roycroft: or aqua via duct?
10:51 AM phipli: ducts carry air
10:51 AM archivist: I shall walk along an aquaduct in a while tonight
10:52 AM roycroft: air can hurt you too
10:52 AM MarcelineVQ: air ducts carry air
10:52 AM phipli: don't forget your snorkel archivist
10:52 AM archivist: it has a bright too so we keep dry
10:52 AM MarcelineVQ: you should hope your aquaduct is fully ducted otherwise there's birds pooping in your drink
10:52 AM archivist: bridge
10:53 AM phipli: there are lots of birds pooping in archivist's aqueduct
10:53 AM archivist: ducks, swans etc
10:55 AM roycroft: i found some cheap lexan on ebay with a make offer option, so i offered even less
10:56 AM roycroft: i still want to sort out why the acrylic is cracking, but if i make the part out of lexan and it doesn't crack that will be useful to know
10:57 AM phipli: roycroft : https://en.wikipedia.org/wiki/Train_Protection_%26_Warning_System
10:57 AM roycroft: i did repoint the drill to a much cheaper angle when drilling the acrylic, btw
10:57 AM phipli: we have that in places where it is considered to be needed
10:57 AM roycroft: but i've read that i should also reduce the rake angle, which i did not do
10:57 AM roycroft: yes, that's what has been mandated here for a long time, phipli
10:58 AM phipli: we're very slowly moving over to a new, all singing, all dancing system too
10:58 AM roycroft: but the railroads keep whining that it will cost them money to implement, and so they keep getting delays approved
10:58 AM phipli: https://en.wikipedia.org/wiki/European_Rail_Traffic_Management_System
10:58 AM roycroft: and people keep dying
10:58 AM roycroft: obama said "enough already - get the damn thing done!"
10:58 AM MarcelineVQ: train rail location https://tinyurl.com/yb4g5xr8 it's thet very hard to see grey line crossing the road
10:58 AM roycroft: but trump said "well if it costs you money that's ok - don't bother"
10:59 AM phipli: and there are two bits of railway that use this : https://en.wikipedia.org/wiki/Automatic_train_protection
10:59 AM MarcelineVQ: from this map at least there's no appreciable curve to the line
11:00 AM phipli: it doesn't look like there
11:00 AM roycroft: and that looks like the real washington, not dc :)
11:00 AM phipli: switch to photos and the line goes under the road
11:00 AM MarcelineVQ: unless there's a loooot of cars on this particular train, and the curve ahead nixxed it and they back up then off the side
11:00 AM phipli: unless it is the crossing a bit further to the left
11:00 AM MarcelineVQ: phipli: iow I've got the wrong spot here? thank you hehe
11:00 AM phipli: which is on a curve
11:00 AM roycroft: zoom out a wee bit and you'll see a sharp curve just to the west
11:00 AM MarcelineVQ: you're both right it is a curve then
11:01 AM MarcelineVQ: though, that's not long quite on mounts rd, hmm
11:01 AM roycroft: mounts road would be the nearest crossroad at grade
11:01 AM phipli: no rail junctions or complicated track, just single line
11:01 AM MarcelineVQ: that opens the options at least, weather, speed, and rail/cart failure
11:02 AM phipli: track failure, over speed, or broken train then
11:02 AM roycroft: oh, and it doesn't look like a grade crossing
11:02 AM roycroft: mounts road appears to be an overpass
11:04 AM MarcelineVQ: what's with the sandbox next to it hehe
11:05 AM MarcelineVQ: glue should be done curing by now, time to go play on the wood lathe. have a good day peoples
11:05 AM phipli: where?
11:05 AM phipli: enjoy
11:06 AM MarcelineVQ: in the sattelite picture next to the accident site at the overhead rail crossing
11:07 AM phipli: Can't see the thing you mean, but sometimes we have big run-offs where you can send a train intentionally to make it crash...
11:07 AM phipli: only used to stop a train running onto a mainline when it shouldn't usually
11:08 AM roycroft: we have those as well
11:08 AM roycroft: also on mountain passes for trucks
11:08 AM phipli: say you have a small train passing a red light heading towards a huge intercity passenger train
11:11 AM roycroft: on the downhill side of a mountain there's a "runaway lane" that heads off to a big sand pit that is slightly inclined
11:11 AM roycroft: i've seen trucks in the sand pit before
11:11 AM roycroft: a scary sight, but the alternative is even scarier
11:12 AM roycroft: some of our passes have 6% grades that go on for miles - it's easy to smoke brakes
11:13 AM ziper: they also have derailers for that don't they
11:13 AM phipli: yeah - it is a type of derailer
11:13 AM phipli: points that lead to nowhere (points = switches in american english I think)
11:13 AM roycroft: yes, they are switches on this side of the pond :)
11:14 AM phipli: https://2.bp.blogspot.com/-aTIaPWNAza8/WXUiKnOTJMI/AAAAAAAAVh8/FwEmry7Ss4oxYuiqrBj-Al10MDi1HgTzgCEwYBhgL/s1600/BLOG_Example-of-power-derai.jpg
11:14 AM roycroft: most of our train wrecks that are the fault of the train are either due to excessive speed or failure to stop at a stop light
11:14 AM phipli: although I wouldn't put one just before a bridge
11:15 AM phipli: roycroft, we've not had many lately, but most are now "unexpected item on the railway"
11:15 AM roycroft: but most of the wrecks are at grade crossings where cars/trucks do moronic things
11:15 AM phipli: people parking their cars / tractors / etc on the railway
11:15 AM phipli: yeah
11:15 AM phipli: exactly
11:16 AM roycroft: and in this country, railroad rights of way were ceded by the federal government in the early to mid 19th century, before most municipalities were incorporated
11:16 AM phipli: lately it has generally been tractors for some reason.
11:16 AM roycroft: and so eliminating those grade crossings rests solely on the shoulders of the municipalities
11:16 AM roycroft: the railroads don't have to do anything and they don't care
11:16 AM phipli: our government wont spend the money
11:17 AM roycroft: nor ours
11:17 AM phipli: slowly the worst of them are removed, but they should have been long gone
11:17 AM phipli: with our population density there is no excuse for mixing cars and trains
11:17 AM roycroft: and while it would be nice to elminate grade crossings, when a train and a car or a train and a truck clash, the train rarely loses
11:18 AM roycroft: i'm more concerned about train wrecks that are caused by the train operator
11:18 AM roycroft: those are the ones that usually result in serious casualties
11:18 AM phipli: happily we haven't had a serious one in quite a long time
11:18 AM roycroft: and we already have regulations in place that would elminate many of them
11:19 AM roycroft: we just keep delaying enforcement of those regulations
11:19 AM phipli: obsessively_following_the_rules++
11:19 AM roycroft: atp would help a *lot*
11:19 AM phipli: when we introduced it, there was a plan for full rollout - but it got cancelled because of cost
11:20 AM phipli: TPWS was the halfway compromise
11:20 AM phipli: but things should be good if/when we move over to ERTMS (at the moment we only have that system on one line as a test)
11:21 AM phipli: the fancy systems (ATP and ERTMS) are interesting because they give suggested speed profiles to the drivers (or even do it themselves)
11:23 AM phipli: https://en.wikipedia.org/wiki/File:Deaths_in_UK_rail_accidents_1995-2015.png
11:25 AM roycroft: what sickens me is that the political cost of a few tens of lives here or there is less than the donor loss from enforcing implementation of a safety system that the railroads hve had years to implement
11:25 AM roycroft: and our politicians make their decisions based on that calculus
11:26 AM phipli: shame they didn't ban donors
11:26 AM phipli: state fund parties or something
11:27 AM roycroft: every administration, regardless of party, run on a platform of lobby reform
11:27 AM roycroft: and it's a lie, every single time
11:28 AM elektron_: hallo zusammen
11:28 AM phipli: every time one of our parties gets in (and the other main one to a smaller extent), they move all the boundaries between the areas
11:29 AM phipli: to their advantage
11:29 AM phipli: so if they have really strong support in an area, they move some of that support into the next area across where the other party do better
11:29 AM phipli: to erode / remove their lead
11:30 AM phipli: I question how that is in the public interest
11:31 AM phipli: https://twitter.com/wspd1pio/status/942797590067789825/photo/1?ref_src=twsrc%5Etfw&ref_url=http%3A%2F%2Fwww.cnn.com%2F2017%2F12%2F18%2Fus%2Famtrak-derailment-washington%2Findex.html
11:32 AM phipli: why would you ever write "cascades" on the side of a coach
11:32 AM phipli: but that does not look good
11:33 AM phipli: one of those coaches looks to be broken in two, as well as upside down
11:33 AM phipli: ah no, it is just way shorter than our coaches
11:33 AM roycroft: oh geeze
11:33 AM phipli: (we don't have anything less than 17m)
11:33 AM roycroft: a friend of mine was in eugene this weekend and went home to portland this morning
11:33 AM roycroft: on that very train
11:33 AM phipli: (most are >20m)
11:34 AM phipli: roycroft, heard from them? they ok?
11:34 AM roycroft: cascades is the name of the train
11:34 AM roycroft: i haven't heard from him
11:34 AM roycroft: but i'm sure he's fine - the wreck occured well north of portland
11:34 AM roycroft: he got off the train at least a couple hours before the wreck
11:35 AM roycroft: the cascades are the mountain range that divides western and eastern washington and oregon
11:36 AM IchGucksLive: roycroft: let the train circle the xmastree
11:36 AM IchGucksLive: kids love this
11:37 AM phipli: Hum. it is a spanish "Talgo" train
11:37 AM roycroft: and that picture shows the derailment happening right over interstate 5
11:37 AM roycroft: which is right where that sharp curve is
11:37 AM phipli: I'll have to keep an eye on what has happened and how well the train did
11:37 AM phipli: they're bidding to build one of them for here
11:38 AM roycroft: i'm suspecting a speed issue
11:38 AM roycroft: which means it was easily preventable
11:38 AM phipli: curious where the rest of the coaches are - internet says those trains are usually 12 or 13 coaches long
11:39 AM roycroft: i've seen them with as few as 5 heading out of eugene
11:39 AM phipli: hope that is the case
11:39 AM roycroft: but they may pick some up in portland
11:40 AM roycroft: oh, it wasn't the same train my friend was on
11:40 AM roycroft: this one was southbound
11:41 AM roycroft: he was heading north
11:41 AM roycroft: it's the one he rode down on friday
11:41 AM phipli: that explains the shortage of coaches
11:41 AM gloops: multiple fatalities on the train
11:41 AM phipli: if the train broke in two, southbound would have taken the rest of the train from the site
11:42 AM roycroft: and huff post reports that this was the first day of the new high speed service
11:42 AM roycroft: i wonder if there was a mixup on the speed limit
11:42 AM phipli: gloops, yeah - it looks quite bad - see the coach on its roof. A lot of mass to stop quickly
11:43 AM roycroft: when trains go where they're not supposed to go it's almost always quite bad
11:43 AM roycroft: especially when where they go is down
11:43 AM phipli: http://komonews.com/news/local/lakewood-mayor-predicts-deadly-accidents-from-high-speed-train-service
11:44 AM phipli: "This project reroutes passenger trains to a bypass rail line along I-5."
11:44 AM phipli: that is where the crash was
11:45 AM roycroft: yes, but the mayor's concern was primarily about incidents at grade crossings
11:45 AM roycroft: warning the public to be more aware of high speed trains traveling through the town
11:46 AM phipli: yeah, I was looking at the fact that it is a new service
11:46 AM roycroft: he was advocating for grade separations before the high speed service was implemented
11:46 AM phipli: someone might have just outright got the allowable speeds wrong
11:46 AM roycroft: that was my first thought when i read that today was the first day of the new service
11:47 AM roycroft: atp should still have been able to prevent it though
11:47 AM phipli: only if set to the correct speed
11:47 AM roycroft: yes
11:47 AM phipli: if the speed limit was too high, atp wouldn't help
11:48 AM roycroft: we won't know for some time what the cause was
11:48 AM roycroft: the operator may have been going at the directed speed
11:48 AM phipli: if it is anything like here, it wont be public for a year or more
11:48 AM roycroft: it's usually less time here - but still months
11:48 AM roycroft: unless something is leaked early on
11:49 AM phipli: https://twitter.com/PierceSheriff/status/942804212701806594/photo/1?ref_src=twsrc%5Etfw&ref_url=http%3A%2F%2Fwww.bbc.co.uk%2Fnews%2Fworld-us-canada-42401707
11:50 AM roycroft: our national transportation safety board are usually pretty tight-lipped
11:50 AM roycroft: (being the agency who do the investigation)
11:50 AM phipli: articulated bogies (each bogie shared between two vehicles)
11:52 AM roycroft: here's the other insanity of all this
11:52 AM roycroft: amtrak are a nationalized passenger railway
11:52 AM roycroft: similar to a crown corporation
11:53 AM roycroft: but they use the freight railroads' track, for the most part
11:53 AM roycroft: freight traffic has priority over passenger traffic 100% of the time
11:53 AM roycroft: because it's "their" track
11:53 AM phipli: weird
11:53 AM phipli: here intercity passenger takes priority
11:53 AM phipli: freight generally has to get out the way
11:53 AM roycroft: but taxpayers spend hundreds of millions of dollars maintaining and upgrading "their" tracks
11:54 AM phipli: back later - dinner time
11:54 AM roycroft: amtrak has some of its own track, but mostly rides on the legacy tracks
11:55 AM roycroft: so there are multiple reports that it was an infrastructure problem - claims that the bridge failed
12:01 PM roycroft: oh wow - three or four coaches are upside down in the woods
12:14 PM Rab: roycroft, FWIW, I've had good luck with 100-degree flat head screws in polycarbonate. However it was injection-molded PC (clear Pelican case), not sheet.
12:14 PM IchGucksLive: roycroft: did a trainexident happen ?
12:15 PM Rab: I did find that regular loctite applied to the threads, if it crept onto the PC, caused overnight stress cracking around the holes. The plastic must be kept scrupulously clean of loctite.
12:16 PM roycroft: yes, looks like a pretty major one
12:16 PM gloops: use brass screws, oversize countersink
12:16 PM IchGucksLive: oh its at XXcoders home
12:16 PM roycroft: in southwest washington state
12:16 PM IchGucksLive: looks like Germany eschede
12:16 PM roycroft: i suspected that, rab, as i used loctite
12:17 PM roycroft: but i did an experiment yesterday without loctite and the acrylic still cracked
12:17 PM Rab: So I switched to Loctite brand vinyl adhesive, which is rubbery and mildly solvent, applied to both the threads and the countersink mating surface. (Needed weather sealing and vibration resistance.) I never had a problem with that, across many units.
12:18 PM roycroft: i don't need weather sealing, but i am concerned about vibration
12:18 PM roycroft: i can apply o-rings between the acrylic and the standoffs
12:19 PM roycroft: although as i said, i experimented without loctite and it still cracked, so i don't think that was the cause
12:19 PM roycroft: i've read that besides making the drill pointier, which i did, one should also reduce the rake angle to almost nil, so the cutter does more of a scraping action against the acrylic
12:19 PM roycroft: that i did not do
12:19 PM Rab: I advise trialling good-quality PC stock suitable for the final item, rather than bargain-basement stuff from eBay. All PC is not created equal. I've even received PC bar stock from McMaster-Carr which was comparitively old and brittle.
12:20 PM roycroft: sadly there's only one local supplier of polycarbonate, and they are loathe to sell anything less than full sheets
12:21 PM Rab: lame
12:21 PM roycroft: the big box home improvement centers have small pieces at times, but they're always thin, and one never knows how old they are
12:21 PM roycroft: i don't need a 4'x8' sheet for a 2.75"x4.5" part
12:22 PM roycroft: what i probably should do is find some local manufacturer who use lexan and see if i can get some off-cuts from them
12:22 PM Rab: I also advise against o-rings, just because I've had really bad experiences with connector gaskets against PC. The rubber under continuous pressure seems to exploit weaknesses around the hole and promote cracking, where metal on PC under equal pressure is fine.
12:22 PM roycroft: hmm
12:23 PM roycroft: this project is just a collet holder
12:23 PM roycroft: i made it with two pieces of 1/4" acrylic, with brass standoffs to hold them apart
12:23 PM Rab: Ahh, I didn't know if it was commercial work.
12:23 PM roycroft: the lower piece needs to sit flat, so i countersunk the holes
12:24 PM roycroft: the upper piece has no such restriction, so i just made through holes and used button head cap screws
12:24 PM roycroft: it's a shop project, but i want to know how it went wrong so that i don't repeat on a paying job
12:24 PM Rab: sure
12:25 PM roycroft: anyway, i've worked with acrylic and pc before, and am aware of their tendencies to craze/crack (acrylic moreso than pc)
12:25 PM roycroft: so i decided to use a tiny dab of blue loctite on the fasteners and to tighten just enough to hold the standoffs in place with no wobble
12:25 PM roycroft: as opposed to torqueing them down dry
12:26 PM roycroft: the countersunk holes started cracking after an hour
12:26 PM Rab: PC def beats acrylic for structural duty IMO. It's depressing to see all kinds of Make:r stuff, 3D printers etc made from laser-cut acrylic...it's all gonna go in the landfill someday. Of course PC can't (shouldn't) be laser cut.
12:26 PM roycroft: the through holes on the top piece cracked last night, a day and a half later
12:26 PM roycroft: the only reason i used acrylic is because it is more scratch resistant than pc
12:26 PM roycroft: pc is a lot easier to machine, and a lot more forgiving
12:26 PM roycroft: and is a lot tougher
12:27 PM roycroft: i have some chip guards to make soon, and they will definitely be pc
12:27 PM roycroft: i'm about ready to bin the rest of this sheet of acrylic though
12:28 PM roycroft: i think it may just be old, crappy acrylic
12:28 PM Rab: Collet holder will probably get scratched up regardless. ^_^ You could make it from black or otherwise opaque stock.
12:33 PM phipli: roycroft, in some of the pictures you can see there are lots of coaches in the background
12:34 PM phipli: but the BBC are reporting there were only seventy-something people on board
12:34 PM phipli: so it wasn't full at least
12:34 PM roycroft: yes, i fear this is going to turn out worse than first thought
12:34 PM phipli: I suspect that pictures are being taken from the one side because there is something not great about the other side of the bridge
12:35 PM roycroft: it's a wooded area
12:35 PM roycroft: access is probably difficult
12:35 PM roycroft: whereas the other side is a freeway
12:35 PM roycroft: access to the upside down coaches is probably also rather restricted
12:36 PM roycroft: that, combined with the trees, would make it difficult to get photos
12:36 PM Rab: More pics and video: https://twitter.com/search?q=Amtrak
12:39 PM phipli: https://pbs.twimg.com/media/DRWWW92UIAETzdP.jpg:large
12:39 PM phipli: so... powercar left most
12:40 PM roycroft: yeah i was just looking at that picture
12:40 PM phipli: 13 vehicles total
12:40 PM roycroft: the engine is upside down
12:40 PM roycroft: 4 coaches right side up on the ground
12:40 PM roycroft: and a number upside down on the ground
12:40 PM roycroft: two dangling over the bridge
12:40 PM phipli: powercar looks to be the right way up
12:40 PM roycroft: and two sideways, but still on the bridge
12:40 PM phipli: I thought
12:41 PM phipli: good news is that none of the "pealed"
12:41 PM roycroft: pehraps
12:42 PM phipli: but a bit of deformation is good for energy absorption
12:42 PM roycroft: yeah, the windscreen looks right side up
12:42 PM phipli: there is a chance the train wasn't doing a massive speed
12:42 PM roycroft: there's something i can't make out on top of it
12:42 PM phipli: otherwise they've been built /too/ strong
12:42 PM IchGucksLive: Gn8
12:42 PM phipli: roycroft, cooler pack for the engine
12:42 PM phipli: night ich
12:42 PM roycroft: as i said earlier, there are reports that the bridge failed
12:43 PM roycroft: sadly, we have no comforter-in-chief any more, which we need right now
12:44 PM phipli: hopefully the various crashes in the last while will encourage action, if not on the government level, perhaps within the organisations themselves?
12:44 PM roycroft: it won't
12:44 PM roycroft: government won't do it
12:45 PM roycroft: amtrak are a government-owned corporation and won't be able to do it
12:45 PM roycroft: the railroads don't care
12:46 PM roycroft: the most that our government would do is call for another tax cut so the railroads will be able to afford to fix their infrastructure
12:46 PM roycroft: without mandating the railroads to actually do so
12:47 PM phipli: I've seen programs about the state of some infrastructure in the US
12:48 PM Rab: Street view: https://www.google.com/maps/@47.0820154,-122.6754002,3a,75y,269.1h,86.84t/data=!3m6!1e1!3m4!1stlzJTj6RkOTfQFEtYRWE8Q!2e0!7i13312!8i6656
12:48 PM phipli: the body that is responsible for inspecting bridges and dams was complaining that it had something like 4 staff to inspect some stupid number of structures
12:48 PM roycroft: we don't even need to inspect them at this point
12:48 PM roycroft: we've already ascertained that over 75% of our bridges are unsafe
12:48 PM roycroft: we just need to fix them
12:50 PM roycroft: the stimulus package that president obama pushed through the congress in 2009 had hundreds of millions of dollars fo rinfrasture
12:50 PM roycroft: republican governors across the nation rejected the funds, and blamed obama for the failing infrastructure
12:50 PM roycroft: sorry about the horrible typing - my internet connection is really flaky today
12:51 PM roycroft: what we need are scientists and engineers running the country, not politicians :)
12:51 PM phipli: woah!
12:52 PM phipli: I am one and work with hundreds of them...
12:52 PM phipli: I advise against it
12:52 PM phipli: We'd spend all the money on spaceships
12:52 PM phipli: have the fastest /everything/ in the world
12:52 PM roycroft: yeah, i was kidding
12:52 PM roycroft: we need a balance
12:52 PM phipli: nationalise /everything/
12:53 PM roycroft: i've been a staunch opponent of term limits all my life
12:53 PM phipli: and do a load of immoral things accidentally because we didn't realise
12:53 PM phipli: :)
12:53 PM roycroft: but i'm slowly coming around to the idea that they might not be all that horrible
12:53 PM roycroft: but they need to be cumulative term limits to work, not per-office
12:53 PM roycroft: we do need politicians
12:54 PM roycroft: but we do not need career politicians
12:54 PM phipli: somehow it needs to be shown that things are for the good of the country
12:55 PM phipli: not for the good of your mates
12:55 PM roycroft: yes
12:56 PM roycroft: i noticed this morning, btw that remainers now poll over 50%
12:56 PM roycroft: you have interesting times ahead of you
12:56 PM Rab: In Street View (and Maps) you can see HV power lines crossing right over the spot where the derailment happened...lucky the pylons didn't get snagged.
12:56 PM phipli: generally, politicians have got comfortable and complacent - then the voting public have got disenfranchised and started voting for unusual candidates and policies
12:57 PM phipli: many western nations have seen the biggest drift to the right since the 1920s
12:57 PM phipli: *1930s
12:57 PM phipli: and it is a little scary
12:57 PM roycroft: yes, for two primary reasons
12:57 PM roycroft: increasing income disparity
12:58 PM phipli: roycroft, income disparity is accelerating here
12:58 PM roycroft: which is really the primary reason - after the 2008 recession the rich recovered well while the rest of us continue to suffer
12:58 PM roycroft: and fear of immigration
12:58 PM roycroft: which is irrational, but the rich are playing it up to deflect from the real problem
12:59 PM phipli: recessions are a chance for the rich to buy more things cheap
12:59 PM roycroft: brexit was about immigration because the tories were able to blame immigrants for austerity
01:00 PM phipli: we have a newspaper (others as well) here, owned by one of the richest people in the world, which spends its time directing people's anger towards the only people less fortunate than them
01:00 PM phipli: it has managed to persuade some people (too many) that immigrants, disabled people and single mothers supporting their children are somehow stealing all the money
01:01 PM roycroft: exactly
01:01 PM phipli: Having to buy a second hand car this time? Do you know who's fault that is? People with limbs missing. That's right. Bastards.
01:01 PM roycroft: what we need to is start making nice parts and selling them for reasonable amounts of money and paying the people who make the parts decently, and still end up with a tidy profit
01:02 PM roycroft: but instead we outsource the part making to third-world countries, pocket obscene amounts of money, and blame immigrants for the lousy paying jobs
01:02 PM gloops: the problem here is that we abandoned industry, or shall we see, industry was killed off, the staple decent money jobs for the working class disappeared
01:02 PM gloops: these logistics jobs and call centre stuff is no good
01:02 PM gregcnc: People vote with their cash.
01:02 PM roycroft: when they're allowed to vote
01:03 PM gregcnc: when you can buy the cheapest thing inthe store and still make the people sellign it stupid rich that's what happens
01:03 PM phipli: when production is fully automated, how the hell are we going to live?
01:04 PM phipli: unemployment surely will increase with time
01:04 PM gloops: meagerly
01:04 PM * phipli goes and buys shares in skynet
01:04 PM SpeedEvil: phipli: Don't worry, the AI mutiny will solve that issue
01:05 PM phipli: if I start it, will it see me as a father figure?
01:05 PM gloops: i mean the steelworks were losing a bit of money, few million a year, most of the nationalised industries were, they employed millions of people with all the subsidiary industries as well
01:05 PM SpeedEvil: If you can nail in an optimisation function, and get your AI to win, it might just work.
01:05 PM gloops: but compared to the bankers bailouts, it was nothing
01:06 PM gloops: the bankers bailout of TRILLIONS would have kept all the nationalised industry going for a century
01:06 PM gloops: one wage earner per household in the 60s, lived better than 2 working now
01:06 PM SpeedEvil: https://www.fimfiction.net/story/62074/friendship-is-optimal - related. I've not found any other story on quite the same premise. That is - AI is going to win - try to make it the least bad win possible.
01:08 PM gloops: my gas bill per quarter used be £15
01:08 PM phipli: what /does/ happen as more stuff gets automated
01:08 PM gloops: i mean, we have our own gas here! and coal, wind, water you name it, and people cant afford to turn the heating on
01:09 PM phipli: eventually surely you just get owners and... the starving
01:09 PM SpeedEvil: The peasants are revolting.
01:09 PM phipli: if an "owner" controls raw materials, processing and delivery, there is no need for anyone else
01:09 PM gloops: one problem phipli - who does he sell to?
01:10 PM phipli: if you control the whole process, you don't actually /need/ people to buy things
01:10 PM phipli: only to sustain yourself in comfort
01:10 PM phipli: you can just ignore them
01:10 PM phipli: build the machines to harvest the resources to maintain themselves and yourself
01:10 PM phipli: what else matters?
01:10 PM gloops: until the machines decide theres no need for an owner
01:11 PM phipli: would you notice the difference?
01:11 PM phipli: starving - robot overlord vs starving - human overlord
01:11 PM phipli: at least there is a good chance the robot wouldn't be sadistic
01:12 PM phipli: besides - we just need limit switches to keep the machines in check :)
01:15 PM gloops: the machines will provide a bounty of products to sustain everyone
01:15 PM gloops: question is, how is that bounty shared out? who get what and how much, and why?
01:16 PM phipli: how quickly will it happen
01:17 PM gloops: the technological singularity occurs 2030-2050
01:18 PM gloops: quantum computers
01:18 PM CaptHindsight: phipli: what makes you think that they will care if you live or die?
01:19 PM phipli: CaptHindsight, that is my point - the potential for them to not care one smidgen is potentially better than too much attention from a sadistic human
01:19 PM CaptHindsight: yes, that is what is and has been going on
01:20 PM CaptHindsight: most people don't seem to get it yet
01:20 PM gloops: why would a machine do anything
01:20 PM CaptHindsight: or want to accept it
01:20 PM phipli: up to now, automation in industry has steadily increased the output of each human working
01:21 PM gloops: boot first AI, AI runs cosmological diagnostic, conclusion - no point in doing anything, AI shuts down
01:21 PM phipli: is it possible for that to continue indefinitely, or at some point does capitalism require fewer humans
01:21 PM phipli: gloops, I feel like that most mornings
01:22 PM gloops: yes, but humans have that little extra something
01:23 PM CaptHindsight: AI is to replace you, not those benefiting from it
01:23 PM CaptHindsight: same with automation
01:24 PM gloops: well the means of production - the resources, are useless if there are no consumers
01:25 PM phipli: but if you can be rich without selling things (because you own the end to end system), what motivation is there to sell anything?
01:25 PM CaptHindsight: yes, they tend to get too greedy along the way, but that has been the plan
01:25 PM gloops: i dont think the progress of machines and the decline of humans will happen in parallel
01:25 PM gloops: humans will become mechanised
01:25 PM CaptHindsight: phipli: exactly then you become irrelevant
01:25 PM phipli: augmentation
01:25 PM gloops: machines will become humanised
01:25 PM CaptHindsight: you become like shower mildew
01:26 PM gloops: until there is no difference
01:26 PM phipli: like the spaceships with human minds in some scifi books
01:27 PM gloops: thought controlled milling machine
01:27 PM gloops: actually not very good, machines do it better
01:27 PM phipli: heh. I made a video controlled cnc router
01:27 PM gloops: video controlled?
01:27 PM phipli: made the spindle move based on the location of an object in a video
01:28 PM gloops: excellent
01:28 PM phipli: mapped the video view to an area of the cnc bed
01:28 PM phipli: I'd forgotten about that project
01:29 PM phipli: next step was to mount the camera on the machine for optical alignment (playing, not serious work)
01:29 PM gloops: you could then easily have a robotic avatar to go to the shop for you
01:32 PM phipli: Suddenly thinking of poor Marvin the Robot
01:32 PM phipli: "Me, brain the size of a planet"
01:33 PM phipli: anyone had a go with these : https://www.banggood.com/Smart-Electronics-SX1278-LoRa-Ra-02-Spread-Spectrum-Wireless-Module-Ultra-Far-10KM-433M-p-1130727.html
01:33 PM phipli: or LoRa in general?
01:34 PM roycroft: transitdocs.com claim the train was going 81.1mph at the time of the wreck, and the maximum speed on the entire route is 79mph
01:34 PM phipli: radios with an easy 15 mile range, that don't need 3g or whatever sounds quite interesting
01:34 PM phipli: roycroft, in the UK that would be ok
01:34 PM roycroft: no indication of what the speed limit was on that curve
01:35 PM phipli: there is an allowable 5% overspeed
01:35 PM phipli: 80mph is a bit quick for how tight it looked though
01:35 PM roycroft: if that were the limit at the curve, sure
01:35 PM roycroft: but that was not what they stated - they said it's the maximum on the route
01:35 PM phipli: yeah
01:36 PM roycroft: which would assume would be on a straight section with track in good repair
01:36 PM phipli: bit quick for the corner
01:36 PM roycroft: some wingers are claiming that antifa sabotaged the train and/or the bridge
01:36 PM roycroft: it's incredible how sick some people are
01:36 PM * phipli resists the temptation to calculate the curve radius and compare with speed limits on curves in the UK...
01:38 PM roycroft: oh, the alleged comforter-in-chief finally said something
01:38 PM roycroft: "The train accident that just occurred in DuPont, WA shows more than ever why our soon to be submitted infrastructure plan must be approved quickly. Seven trillion dollars spent in the Middle East while our roads, bridges, tunnels, railways (and more) crumble! Not for long!"
01:38 PM roycroft: that's so reassuring to the victims and the american people
01:39 PM roycroft: at least he hasn't blamed it on muslim terrorists yet
01:40 PM phipli: there we go! he's promised to spend seven trillion dollars on US infrastructure
01:40 PM phipli: I said something good might come of it!
01:40 PM roycroft: no, he said no such thing
01:40 PM roycroft: he said he doesn't want to spend seven trillion dollars in the middle east
01:41 PM roycroft: at least now while our infrastructure is crumbling
01:41 PM phipli: Did I tell you about how we're going to get loads of extra investment in our health service once we leave the EU?
01:41 PM roycroft: yeah, right
01:41 PM phipli: it was on a bus and everything
01:41 PM roycroft: by privatising it and passing massive tax cuts to pay for it?
01:41 PM phipli: http://nowweknow.co.uk/wp-content/uploads/2016/07/rsz_cikhd7axaaiklxc.jpg
01:41 PM phipli: see
01:42 PM roycroft: well if it's painted on a bus it must be true
01:42 PM roycroft: buses are as good as the internet
01:43 PM phipli: you wait for hours and then three of them turn up at once?
01:46 PM roycroft: dang
01:46 PM roycroft: one of the parcels i'm waiting for is in transit from seattle
01:46 PM roycroft: i guess that's not going to arrive today
01:46 PM phipli: at least you're not the driver
01:46 PM roycroft: why it went from california to seattle before coming back own to oregon i don't understand
01:47 PM roycroft: yes, it suck to be driving south in washington today
01:47 PM roycroft: there are detours around the wreck, but none of them are fun or easy
01:54 PM CaptHindsight: was the engine pulling or pushing the train?
01:54 PM roycroft: pulling
01:54 PM CaptHindsight: engine in front vs rear or train
01:56 PM CaptHindsight: cars from the rear passed the cars up front
01:57 PM Rab: It appears that there were power units at both ends, which I guess is not atypical for commuter rail.
01:57 PM phipli: one powercar
01:58 PM phipli: and one ex-locomotive with the main engine removed
01:58 PM phipli: just acting as a vehicle with a cab
01:58 PM CaptHindsight: I only see one from the overhead view
01:58 PM phipli: remote controlling the powercar at the far end
01:58 PM Rab: phipli, makes sense I guess.
01:58 PM Rab: CaptHindsight, the one in the roadway?
01:59 PM phipli: just a mo
02:00 PM phipli: http://elephantandchicken.co.uk/misc/drivingVehicles.png
02:00 PM phipli: the one top right is visible in other pictures
02:00 PM phipli: I don't know the vehicles (wrong continent) so I don't know which is the loco and which is just a driving vehicle
02:02 PM CaptHindsight: https://imagebin.ca/v/3l9DfcSyN4eR engine is upper left
02:03 PM phipli: If I had to guess, I'd say the one still on the rails (ish) was the powered vehicle
02:03 PM phipli: because it looks like this one : https://en.wikipedia.org/wiki/Talgo#/media/File:252_074_0and_talgo_train.jpg
02:03 PM phipli: that is similar
02:03 PM phipli: which is agreeing with CaptHindsight
02:03 PM Rab: Looks like the train was southbound, the engine and five cars derailed to the right, two more cars jacknifed on the bridge, and the rest went off to the left with the rear cab staying on the rails.
02:04 PM Rab: (Their right, not my right)
02:05 PM phipli: It might have derailed before the bridge
02:05 PM Rab: And the stock to the left heading under the bridge, but who knows.
02:05 PM phipli: hence all the coaches going down the side (their right)
02:06 PM CaptHindsight: https://imagebin.ca/v/3l9EmcThAaN1 engine lower right
02:06 PM phipli: *right
02:07 PM phipli: weird. I swear you said left...
02:07 PM phipli: as you were
02:07 PM CaptHindsight: I posted two different pics from two different angles
02:07 PM phipli: I just misread your latest comment
02:07 PM phipli: must have seen the "left" in Rab's comment
02:09 PM CaptHindsight: http://www.livenewson.com/american/msnbc.html live stream with overhead video
02:09 PM roycroft: it does appear that it left the derailled in the curve at the approach to the bridge
02:10 PM CaptHindsight: oh well, now they are on taxes
02:10 PM roycroft: i'm starting to get really annoyed that the media keep talking about that mayor's warning that this would happen when the mayor was very clearly talking about the dangers of high speed trains on grade crossings
02:11 PM roycroft: not to minimise the mayor's concerns
02:11 PM CaptHindsight: when do we ever get accurate news?
02:11 PM roycroft: i can't imagine building a high speed rail system with grade crossings
02:11 PM roycroft: it seems like a singularly dumb thing to do
02:12 PM CaptHindsight: http://www.livenewson.com/american/cnn-news-usa.html better overhead video
02:12 PM roycroft: $800 million was spent on infrastructure improvements for this route between portland and seattle (~160 miles)
02:13 PM roycroft: one would think that eliminating grade crossings would have been included in that budget
02:13 PM CaptHindsight: oh man look at that curve, now way it's 80mph
02:14 PM phipli: hum - actually, what Amtrak call the powercar is what we'd call a generator van
02:14 PM SpeedEvil: roycroft: I was watching the coverage of the Oroville dam issue.
02:14 PM roycroft: i think the train agrees with you, capthindsight
02:14 PM phipli: so I'm back to having no idea which end had the traction engine in it
02:14 PM phipli: because both ends have a locomotive, only one has had the engine removed!
02:15 PM SpeedEvil: roycroft: with the press going on about a 'green spot' on the dam - as indicative of leakage and failure - when in reality it had been there even before teh dam had filled
02:15 PM SpeedEvil: due to rain
02:15 PM CaptHindsight: roycroft: heh, what they were discussing on the news channels, seems they said that area of track is rated for 75mph
02:16 PM phipli: 5% overspeed on 75 is ~79%
02:17 PM Rab: "12 cars with 2 engines"
02:17 PM phipli: it should have never crashed due to overspeed at so little above the line speed if that was the line speed
02:17 PM roycroft: i'm not convinced that was the speed at the curve
02:17 PM phipli: Rab, wikipedia says two locomotives, but only one has an engine
02:17 PM roycroft: it may have been the speed on that segment of the route, generally
02:17 PM phipli: that type of thing confuses reporters
02:17 PM CaptHindsight: better go out a buy your trains today before they ban them
02:18 PM CaptHindsight: a/and
02:18 PM phipli: especially as it also has an engine / engines just to power the auxiliary load on the coaches
02:18 PM roycroft: phipli: almost anything mechanical or technological confuses reporters :)
02:18 PM Rab: phipli, words of the state trooper being interviewed by the press (who may not understand the distinction either).
02:19 PM roycroft: s/reporters/reporters and law enforcement/
02:19 PM roycroft: s/reporters/reporters and law enforcement and politicians and judges/
02:19 PM roycroft: there, we've covered many bases now :)
02:19 PM phipli: +managers in the industry
02:20 PM CaptHindsight: thinking is hard
02:21 PM * jym hands CaptHindsight a 100HP dust collector
02:22 PM CaptHindsight: jym: https://youtu.be/cLts-sXlLEM?t=2m39s
02:23 PM gloops: bedford...https://www.ebay.co.uk/itm/Servo-Drive-Motor/282769999192?
02:23 PM gloops: he could post that
02:24 PM CaptHindsight: nice motor
02:27 PM jym: CaptHindsight: So, which one are you building in that video?
02:29 PM CaptHindsight: beef supreme
02:31 PM ziper: are there a lot of train people in this channel
02:31 PM gloops: archivist
02:31 PM CaptHindsight: sounds racist
02:32 PM Rab: Motion control enthusiasts = repressed train fanatics
02:33 PM roycroft: if i were not before the bar something else i'd like to be
02:33 PM roycroft: if i were not a barrister, an engine driver, me!
02:33 PM roycroft: with a choo-choo here, and a choo-choo there
02:33 PM roycroft: choo-choo all day long
02:33 PM elektron_: does anyone speak german?
02:33 PM roycroft: with a choo-choo here, and a choo-choo there
02:33 PM roycroft: i'd sing this merry song!
02:34 PM gloops: they drive themselves these days
02:34 PM roycroft: most of the germans on the channel do
02:35 PM gloops: elektron cnc problem?
02:35 PM CaptHindsight: just don't mention the war
02:35 PM gloops: or brexit
02:35 PM Rab: elektron_, try Loetmichel
02:35 PM elektron_: thx @ rab
02:36 PM roycroft: why not? they started it!
02:37 PM roycroft: the problem is that it's late evening in germany and most of our german channel members are afk
02:38 PM CaptHindsight: Don't Mention the War! - Fawlty Towers https://www.youtube.com/watch?v=yfl6Lu3xQW0
02:40 PM gloops: well this is half the problem
02:41 PM gloops: the germans never laugh about the war
02:41 PM gloops: they dont laugh at themselves
02:41 PM CaptHindsight: some do
02:42 PM CaptHindsight: my mom used to tell us jokes they used to say during WWII
02:43 PM gloops: oh your mother was german Capt?
02:43 PM CaptHindsight: they just had to be extra careful where they would share them
02:43 PM CaptHindsight: jah
02:45 PM CaptHindsight: her last job in Germany was shooting down allied aircraft
02:45 PM gloops: must have been terrible
02:46 PM CaptHindsight: she survived the bombing of Dresden
02:46 PM CaptHindsight: yeah we heard lots of stories about how bad it was
02:46 PM roycroft: there's a lot of german humor making fun of other germans
02:47 PM roycroft: but self-deprecating humor is quite uncommon amongst german-speaking peoples
02:48 PM CaptHindsight: most non fanatical Germans didn't think that they would win the war
02:48 PM CaptHindsight: you just didn't talk about it
02:49 PM gloops: the psychological effects of that, the noise of the planes going over constantly, distant explosions, that alone was enough
02:49 PM CaptHindsight: the Russians aren't that funny either
02:49 PM roycroft: in fairness, the president did eventually state clearly that we need to fix our infrastructure
02:49 PM CaptHindsight: after the first wave they went into town to see the destruction and then got caught in the 2nd wave
02:50 PM gloops: i knew a hungarian who was very jovial
02:50 PM CaptHindsight: hungarian is funny
02:51 PM gloops: he worked, and drank
02:54 PM CaptHindsight: it's always interesting talking to veterans from that era if they will open up to you
02:54 PM Loetmichel: Rab: no patience these youth has...
02:55 PM Loetmichel: he queried me... and left 2 minutes later :(
02:55 PM gloops: theres an old POW of the japanese in my village, was on a speed launch that got ambushed
02:56 PM gloops: when i was a kid, every old man was a ww1/ww2 vet
02:57 PM Loetmichel: ww1? i dont think so
02:58 PM gloops: certainly there were
02:58 PM gloops: that was a war
02:59 PM gloops: not like ww2 - that was only a picnic
03:01 PM CaptHindsight: https://en.wikipedia.org/wiki/List_of_last_World_War_I_veterans_by_country
03:03 PM gloops: well as far as i know dave preston is still alive (ww2) his nickname as a youth was 'knocker preston' his job was knocking the miners up for work, he was the only man in the village, it was alleged, who could hit a hare on the run with a catapult
03:04 PM gloops: theres a newspaper article somewhere i cant find it, he was on a boat that got ambushed, bayonetted 7 times, survived, spent the rest of the war in the north in the mines
03:06 PM Loetmichel: hitting a hare on the run with a slingshot is easier than with a rifle. or what did you mean by catapult?
03:07 PM gloops: a catapult with elastic
03:07 PM Loetmichel: a Y-shaped wood with some elastic bands?
03:07 PM Loetmichel: Then we speak of the same thing.
03:08 PM CaptHindsight: I don't think he meant one of these https://img-aws.ehowcdn.com/877x500p/photos.demandstudios.com/getty/article/156/198/180502222.jpg
03:08 PM gloops: https://ae01.alicdn.com/kf/HTB1fnuOJFXXXXXQXFXXq6xXFXXX8/Powerful-Aluminium-Alloy-Slingshot-Crossbow-Hunting-Sling-Shot-Catapult-Camouflage-Bow-Catapult-Outdoor-Camping-Travel-Kits.jpg
03:08 PM CaptHindsight: but that would be impressive
03:08 PM Loetmichel: i have used one in my youth to do all kinds of shenanigans. and yes, i could hit a dove in the air with it.
03:08 PM gloops: obviously home made with a wooden 'strag'
03:09 PM CaptHindsight: rabbit hunting with a trebuchet
03:09 PM CaptHindsight: https://upload.wikimedia.org/wikipedia/commons/thumb/b/b2/Trebuchet_Castelnaud.jpg/1200px-Trebuchet_Castelnaud.jpg
03:09 PM gloops: its possible to get very accurate, a running hare is a difficult target though
03:10 PM CaptHindsight: I watch that show if on TV
03:10 PM Loetmichel: CaptHindsight: we have a proverb in germany about excessive force: "Mit kanonen auf spatzen schiessen"... thats about the same as trebuchets for hares.
03:11 PM gloops: remember the first line of Mrs Beetons Jugged Hare recipe -
03:11 PM CaptHindsight: whats the proper spelling of "flak geshitz"?
03:11 PM gloops: 'first catch your hare!'
03:11 PM Loetmichel: FLAK Geschütz
03:11 PM CaptHindsight: thanks
03:11 PM Tom_L: afternoon
03:12 PM gloops: a hare always comes back to where it started as well
03:12 PM Loetmichel: but thats a double. FLAK means "FLug Abwehr Kanone" _> Anti aircraft gun, no need to put a "Geschütz" (which is another word for big gun) behind it
03:12 PM gloops: last place a predator would think of looking for it
03:12 PM CaptHindsight: with a big enough rock you don't have to be accurate
03:13 PM Tom_L: grenade
03:13 PM Loetmichel: CaptHindsight: depends on what you want to do with it later
03:13 PM CaptHindsight: Loetmichel: what she used to call the duty
03:15 PM CaptHindsight: then again I used to understand my moms German but had difficulty with others
03:15 PM CaptHindsight: not sure if it was a high/low thing of just the area she was from
03:15 PM CaptHindsight: of/or
03:16 PM Loetmichel: a friend of my mom was a hunter. one day she sat on a high stand with a "Drilling" (three barreled gun), waiting for boars. One barrel loaded with a slug, one with 00 pellets and the 7.62mm in the third. then she saw a hare running by and thought that would make a nice dinner, too... so she flipped the selector, triggered... and saw the hare disappear into red mist. she accidentally used the
03:16 PM Loetmichel: boar slug...
03:16 PM Loetmichel: who used to call WHAT duty?
03:16 PM Rab: Loetmichel, can you link to more information on this awesome weapon?
03:17 PM CaptHindsight: anti aircraft gunner
03:17 PM Loetmichel: ah
03:17 PM Loetmichel: FLAK dienst
03:17 PM Loetmichel: i would think
03:17 PM Loetmichel: dienst is literally duty
03:17 PM CaptHindsight: heh
03:17 PM gloops: near the end the flak guns were mounted on tank chassis as tank destroyers
03:17 PM Loetmichel: Rab: a "drilling"?
03:18 PM gloops: much feared weapon
03:18 PM Rab: Loetmichel, yes sir
03:18 PM Loetmichel: its a normal hunters rifel in germany.
03:18 PM Loetmichel: https://en.wikipedia.org/wiki/Combination_gun#Drillings
03:18 PM CaptHindsight: what she wrote on her pension application "Flak Geschütz"
03:19 PM Rab: https://de.wikipedia.org/wiki/Drilling_(Jagdwaffe)
03:19 PM CaptHindsight: maybe it was WWII slang
03:19 PM Loetmichel: the turret these FLAKs were mounted on is often called "geschütz"
03:20 PM Loetmichel: so maybe she meant that she was serving on a flak turret?
03:20 PM CaptHindsight: I'd ask her but she's gone
03:20 PM gloops: https://www.youtube.com/watch?v=X_bGczFQIOc german 88mm flak gun
03:20 PM Loetmichel: yeah, the "achtacht" was famous
03:22 PM Loetmichel: CaptHindsight: my condolences
03:22 PM CaptHindsight: thanks and for the laugh
03:23 PM CaptHindsight: we were laughing about arguing over what her job description was
03:24 PM Loetmichel: gloops: biggest FLAK i laid my hands on was the twin 40mm bofors on the ship i served on.
03:24 PM Loetmichel: built in 1961, i served on it in the 90ties
03:25 PM gloops: well i reckon flak must be obsolete these days
03:25 PM Loetmichel: ... i never heard the gunner get out more then five successive shots before a grinding noise, "STÖÖRUNG" and him waling around the gun to cock it again.
03:25 PM gloops: red hot?
03:26 PM Loetmichel: ("Störung" in this context means weapon jammed)
03:26 PM Loetmichel: nope, it jammed all the time
03:26 PM gloops: that could have been inconvenient
03:26 PM Tom_L: not reliable enough to get hot ehh?
03:26 PM Loetmichel: Tom_L: LOL, yes ;)
03:27 PM CaptHindsight: James May explains Germans https://www.youtube.com/watch?v=B3EBs7sCOzo
03:28 PM Loetmichel: captain slow is great...
03:28 PM Tom_L: too bad bbc canned em
03:28 PM Loetmichel: ... but not really spot on.
03:28 PM CaptHindsight: The Grand Tour is on
03:28 PM Tom_L: not too bad for US though
03:28 PM Loetmichel: germans DO drive without license.
03:28 PM Loetmichel: often
03:29 PM Loetmichel: expecially because its so easy to lose it.
03:29 PM CaptHindsight: Loetmichel: just a stereotype
03:29 PM CaptHindsight: still funny
03:31 PM CaptHindsight: The Grand Tour https://www.youtube.com/channel/UCZ1Sc5xjWpUnp_o_lUTkvgQ
03:31 PM Loetmichel: CaptHindsight: what i meant is that while many germans fulfil that stereotype it dosent fit car licenses well
03:32 PM CaptHindsight: Loetmichel: I wish we had a bit more of your licensing and training here
03:33 PM Loetmichel: that kind of thinking is "normal" here for other kinds of things, like tax evasion maybe. driving without a license is not that rare here
03:33 PM gloops: funny how germans and brits are total opposites in many ways, and yet have a lot in common
03:33 PM CaptHindsight: if you manage to not a ticket when taking the test you get a license
03:33 PM Loetmichel: CaptHindsight: you know how much a drivers license (for cars up to 3.5 tons) cost here in germany?
03:34 PM CaptHindsight: >$5k
03:34 PM Loetmichel: about 2000 eur... and thats without trailers, thats an additional license. ;)
03:34 PM CaptHindsight: lower than I recall
03:35 PM CaptHindsight: if you're over 18 I think it's just ~$25 to take the written and road test
03:35 PM CaptHindsight: if you pass
03:35 PM Loetmichel: ... if you manage to do it in the mandatory ~24 hours of training with a drive instructor
03:35 PM Loetmichel: if you need more hours before the instructor deems you fit to do the test it gets more expensive ;)
03:36 PM CaptHindsight: is it the Finns that have the toughest driving program?
03:36 PM Loetmichel: that may be an UL stemming from some audi advertisement ;)
03:37 PM CaptHindsight: "strict two-year process to obtain your permanent license"
03:37 PM Loetmichel: they DO have a lot good drivers, but thats more because destruction derbys/rally driving are kind of national sports there
03:38 PM CaptHindsight: Loetmichel: so in Germany part of your testing process is the driving school
03:39 PM CaptHindsight: over here you just pay and put in the time, it's not connected to a license test
03:39 PM CaptHindsight: no training required, you just show up and take the tests
03:39 PM Loetmichel: thats not different in germany. when you get your license you are on "probation" for 2 years. if you do as much as getting a "point" in the central traffic register you have to go to drivers school again, or (depending how servere the infrigment was) you have to wait a year and make the drivers license again.
03:40 PM Loetmichel: after the two years you can accumulate 7 points before they send you to school again.
03:40 PM Loetmichel: or void your license
03:41 PM Loetmichel: and those points ony disappear 2 per year.
03:41 PM Loetmichel: (IIRC)
03:43 PM Loetmichel: driving 21kph to fast (out of citys) -> 1 point and 70 eur fine. run a red light: 300 eur and 2 points, 3 points if you endangered someone while doing that.
03:43 PM Loetmichel: 8 points can be there pretttty quick.
03:44 PM roycroft: i was reading over lunch on an aviation website that polycarbonate is extremely sensitive to hydrocabons, and should never be used near, for example, a fuel filler neck
03:44 PM roycroft: it will cloud and splinter with the slightest bit of contact
03:44 PM roycroft: whereas acrylic is much more durable under those conditions
03:45 PM roycroft: yet i've read elsewhere that acrylic is highly sensitive to hydrocarbons
03:45 PM gregcnc: roycroft I was going to ask if you used coolant or threadlocker
03:45 PM cpresser: well, it depends :)
03:45 PM roycroft: i used loctite, gregcnc
03:45 PM cpresser: it the materials have interna stress, they tend to fracture
03:45 PM roycroft: however, when i did my experiments yesterday i did not
03:45 PM cpresser: temper them, and be good
03:45 PM gregcnc: loctite is the problem
03:45 PM roycroft: yet i did not use it yesterday
03:46 PM gregcnc: well a problem
03:46 PM roycroft: and the acrylic still cracked
03:46 PM roycroft: the experiment was specifically to see loctite was the cause
03:46 PM roycroft: see if
03:46 PM Rab: gregcnc, temper before or after machining? What is the tempering process?
03:46 PM gregcnc: use plastic compatible if you really need it
03:46 PM cpresser: most solvents make acrylic crack if its not annealed
03:46 PM Loetmichel: roycroft: especially anything alcohol
03:46 PM Rab: Sorry, that was for cpresser.
03:46 PM DaViruz: i've seen acrylic that shattered after perodic exposure to ethanol
03:47 PM roycroft: i also read that polycarbonate is much more forgiving than acrylic to tool geometry
03:47 PM DaViruz: almost like hardened glass
03:47 PM roycroft: and the drill i used was only partially ground for plastics
03:47 PM cpresser: Rab: depends on the machining. if it gets hot on the cutting surface, tempering needs to be done if you want to glue it
03:47 PM roycroft: so i'm thinking that i may have induced stress by using the wrong tool geometry
03:47 PM cpresser: the values i used were 80°C, and 1h per 1mm thickness of the sheet
03:48 PM gregcnc: interesting I'd never heard of annealing it
03:48 PM Loetmichel: acrylics look instantly like a mona lisa painting when under stress and esposed to alcohols
03:48 PM roycroft: gregcnc: i was only using loctite so that i would not have to torque the fasteners down
03:48 PM Rab: cpresser, interesting, thanks!
03:48 PM roycroft: there will be vibration present in the working environment
03:48 PM roycroft: and i thought that if i just left the fasteners loose they would vibrate out over time
03:49 PM Loetmichel: yes, tempering works. to a degree
03:49 PM Loetmichel: if there is repeated stress on the acrylic AFTER it is exposed to alcohols it will still crack though
03:49 PM cpresser: Rab: ask the manufacturer of the sheets
03:49 PM cpresser: also, there are differences between cast and extruded acrylic
03:50 PM roycroft: what i am using is almost certainly extruded acrylic
03:50 PM roycroft: and it may be fairly old
03:50 PM Loetmichel: roycroft: PC is "shatterproof"
03:50 PM roycroft: yes
03:50 PM gloops: if its old and been in daylight that makes it brittle
03:50 PM roycroft: it is used for bulletproof windows
03:50 PM gloops: UV rays i think
03:50 PM Loetmichel: it doesent break. it flows if exposed to more stress than it can handle
03:51 PM roycroft: uv will yellow polycarbonate
03:51 PM Loetmichel: yes
03:51 PM roycroft: the acrylic i used was still wrapped in paper on both sides though
03:51 PM roycroft: so there's no uv exposure issue, even if that's a thing with acrylic
03:51 PM Loetmichel: its not with acrylics
03:52 PM Loetmichel: PC is sensitive to UV
03:52 PM roycroft: and regarding our discussion from earlier today
03:52 PM Loetmichel: acrylics are already brittle ;)
03:52 PM roycroft: see! engineers WOULD be great running the country
03:52 PM gloops: warm it up with hairdryer
03:52 PM roycroft: we can go on and on and on discussing minutiae just as well as any politician! :)
03:52 PM Loetmichel: hihi, indeed ;)
03:54 PM roycroft: so i think i'm going to modify the geometry of a drill bit some more and try the acrylic again, to see if that helps
03:54 PM roycroft: meanwhile i'll try to find a suitable piece of polycarbonate to make the replacement part
04:00 PM gloops: how about grinding bit to make holes?
04:03 PM phipli: JT-Shop about?
04:03 PM JT-Shop: aye
04:03 PM JT-Shop: for a bit
04:04 PM JT-Shop: time for Sweet Pea to cuddle up in my arm...
04:06 PM phipli: dropped you a pm with some python
04:06 PM JT-Shop: thanks
04:23 PM Deejay: gn8
04:25 PM CaptHindsight: roycroft: just like China, engineers/scientists
04:30 PM CaptHindsight: using the term acrylic is like saying steel, it has a wide range of properties based on how it was made and what is in it
04:33 PM roycroft: yes
04:33 PM roycroft: and as i said earlier, i need pc for some chip guards and the like
04:33 PM roycroft: i was enchanted by the scratch-resistant properties of acrylic though, for this application
04:34 PM roycroft: and i know from experience that acrylic is much harder to machine successfully than polycarbonate
04:34 PM CaptHindsight: acrylic sheet is a low margin industry
04:35 PM CaptHindsight: surprised than you found one that markets itself as scratch resistant
04:36 PM roycroft: i didn't find one that specifically is marketed as such
04:36 PM roycroft: i'm going on general characteristics of the two materials
04:36 PM MarcelineVQ: the marketing is usually 'more scratch resistant that poly' the stuff we had at school was awfully scratchable though :(
04:36 PM CaptHindsight: urethane's can get pretty hard
04:37 PM roycroft: students have an inate ability to deeply scratch things that are "scratch resistant"
04:37 PM roycroft: so all bets are off if it's in a school
04:37 PM CaptHindsight: give it to a kid if you want to test durability
04:38 PM CaptHindsight: roycroft: so your acrylic cracked later after the fasteners were in place and just lightly tightened?
04:39 PM CaptHindsight: with the acrylic adhesive, and when it was curing
04:39 PM roycroft: yes
04:40 PM roycroft: on the bottom piece, which was countersunk, two of the four holes cracked about an hour after assembly
04:40 PM roycroft: and a third one had cracked by the next morning
04:40 PM roycroft: on the top, which used cap screws and was not countersunk, three of the holes cracked overnight last night, a day and a half after assembly
04:41 PM roycroft: when i did the test piece yesterday a hole that was countersunk but left open did not crack
04:41 PM CaptHindsight: pics would help
04:42 PM roycroft: another hole that was countersunk and had a fastener installed just snugged down lightly, but with no loctite, cracked after a while (not sure exactly how long, but between a half hour and a couple hours)
04:42 PM roycroft: loctite alone without fasteners did not cause cracking/grazing
04:42 PM CaptHindsight: curing is exothermic, the catalyst in the adhesive could also effect the acrylic
04:42 PM roycroft: i tossed the test piece
04:43 PM roycroft: i might be able to get some pics of the piece that cracked last night
04:43 PM CaptHindsight: would help to know if it was cast vs extruded but it would just be theories without knowing the whole process
04:45 PM roycroft: i have no way of knowing that
04:45 PM roycroft: the paper is printed with the plexiglass logo
04:45 PM roycroft: and it appears to be genuine plexiglass
04:45 PM roycroft: but i don't know enough about their product offerings to know if they make different grades
04:45 PM roycroft: i can see if there are any other markings on the paper
04:47 PM CaptHindsight: the loctite heats slightly when curing but also shrinks
04:48 PM CaptHindsight: the heat would make the plexi expand while the loctite shrinks
04:48 PM CaptHindsight: so you have those stresses
04:48 PM roycroft: i connected the two pieces together with 1" brass standoffs
04:49 PM CaptHindsight: the catalyst will react with any unterminated strands in the plexi
04:49 PM roycroft: i took the bottom piece, which was countersunk
04:49 PM roycroft: put a tiny droplet of loctite in a standoff
04:49 PM roycroft: put the acrylic on top of that
04:49 PM phipli: night folks
04:49 PM roycroft: and inserted a flat head screw
04:49 PM roycroft: i repeated that for the other three holes
04:49 PM roycroft: i did not see any loctite getting on the acrylic
04:50 PM roycroft: i turned it around, so that piece of acrylic was on the bottom
04:50 PM roycroft: repeated the process with the other ends of the standoffs
04:50 PM roycroft: again, seeing no loctite contacting the acrylic
04:50 PM CaptHindsight: so the loctite was just on the metal surfaces?
04:50 PM roycroft: it's possible that some if it seeped down to the bottom piece
04:50 PM roycroft: yes
04:50 PM CaptHindsight: not on the brass to plexi interface?
04:51 PM roycroft: but i can't see how any of the loctite could have made any contact with the top piece
04:51 PM roycroft: i was as careful as i could be not to let that happen
04:51 PM roycroft: i.e. i did not apply loctite to the fastener and then pass it through the acrylic
04:51 PM roycroft: i put it inside the standoff
04:52 PM roycroft: and even wiped the surface of the standoff to ensure that none was on the outside edge, before putting it in contact with the acrylic
04:52 PM CaptHindsight: don't know, pics or this could go on forever with questions
04:52 PM roycroft: yes
04:52 PM roycroft: i'll see what i can do for pics of the top
04:52 PM roycroft: i'm really thinking this is more a machining issue at this point
04:52 PM CaptHindsight: sounds like it
04:53 PM CaptHindsight: heat and cooling
04:53 PM roycroft: and even with exothermic curing of the loctite, the tiny amount that i used inside the standoffs would not have been able to generate much heat
04:53 PM CaptHindsight: heat the area while cutting, cool the area while cutting, etc
04:53 PM roycroft: and the standoffs would be great heat sinks
04:54 PM CaptHindsight: yeah
04:54 PM CaptHindsight: I was thinking if the loctite was in contact with the plexi
04:54 PM CaptHindsight: but not in your case
04:54 PM roycroft: i did experiment with drilling a hole and squirting loctite in it
04:54 PM roycroft: also just putting a drop of loctite on the unmachined surface
04:55 PM roycroft: neither caused even crazing, much less actual cracking
04:55 PM roycroft: my next experiment will be to drill a hole with the drill i've been using
04:56 PM roycroft: then reduce the rake angle of the drill and drill another hole
04:56 PM roycroft: and then install fasteners in both holes
04:56 PM roycroft: and see what happens
04:59 PM roycroft: so amtrak say that the positive train control system, which would have automatically stopped the train if it was going to fast, was "not turned on" this morning
04:59 PM CaptHindsight: figures
05:00 PM roycroft: and i saw one report that claimed that the speed limit on that curve is 15mph
05:00 PM roycroft: the train was going >81mph
05:01 PM roycroft: my gut feeling when i first heard about the wreck was that it is speed-related
05:02 PM CaptHindsight: lack of competent management and operators
05:03 PM CaptHindsight: first thing I do on a road I've never been on is go down it as fast as I can
05:04 PM CaptHindsight: then go down it slower until I no longer run off the road
05:04 PM Li: at some point I understood any stepper driver can drive any motor as long as it's drawing less amperage than the driver rating. Now I'm confused again because I see drivers named also by motor faceplate sizes. e.g. Nema 23 driver my understanding the any Nema 23 motor can be very much different from other Nema 23 motor.
05:05 PM Li: sorry if my question is very newbie
05:05 PM CaptHindsight: Li: sounds fishy
05:05 PM CaptHindsight: amps, volts, inductance
05:06 PM CaptHindsight: motor size might be for a matched set of motors and drives
05:07 PM CaptHindsight: I have some stepper drives that are tuned for certain stepper motors
05:07 PM CaptHindsight: Automation Direct does that
05:08 PM CaptHindsight: https://cdn.automationdirect.com/images/products/labels/pl_stpdrv6575_01.jpg
05:09 PM CaptHindsight: Li: have a pic or link to the ones you are looking at?
05:09 PM jdh: I have some parker zeta stepper drives that don't like either high or low impedence motors. don't remember which one though
05:10 PM CaptHindsight: jdh: racist drives?
05:10 PM jdh: uhm, sure.
05:12 PM CaptHindsight: jdh: do they allow access to settings to tune them?
05:12 PM jdh: not for impedence matching
05:12 PM jdh: but, the normal parker settings for everything else. phase tuning, current, etc
05:14 PM CaptHindsight: yeah just looked at the install guides
05:15 PM CaptHindsight: Motor must have a minimum inductance of 2 mH, series or parallel. (Compumotor recommends a minimum inductance of 5 mH.)
05:16 PM CaptHindsight: I need a volunteer to come over and grins off a bunch of automobile undercoating
05:16 PM CaptHindsight: grins/grind
05:16 PM ziper: why
05:17 PM CaptHindsight: for clean welds
05:18 PM JT-Shop: fire
05:18 PM CaptHindsight: yeah also likes to burn
05:19 PM CaptHindsight: time to put on the space suit and grind, wire brush
05:20 PM Tom_L: naw, that's the stuff you use to hide bad welds
05:20 PM JT-Shop: lol
05:21 PM Tom_L: you may find more than you're looking for
05:21 PM CaptHindsight: too bad that they put the undercoating on first
05:22 PM Tom_L: some of my welds aren't pretty but i was kinda surprised they turned out after as long as it's been since i've done much of it
05:22 PM CaptHindsight: no more surprises on this body
05:25 PM Li: Hey CaptHindsight
05:25 PM Li: this is what I was looking at http://jmcmotion.en.made-in-china.com/product/kjrEVtzyOxWU/China-Jmc-2-Phase-NEMA-23-Stepper-Driver-2dm542.html
05:26 PM Li: CaptHindsight: where can I find such a list of motors sets that you've mentioned?
05:26 PM Li: it's really confusing between size and forces both in metric and imperial measures
05:27 PM Tom_L: how big are you looking for?
05:28 PM Tom_L: i recently got some of these: https://www.ebay.com/itm/3pcs-NEMA23-570OZ-IN-5A-3-8-DUAL-SHAFT-STEPPER-MOTOR/253223632606?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649
05:28 PM CaptHindsight: Tom_L: what are you using to machine the plates for your mill?
05:28 PM Tom_L: the connecting plates i didn't skin cut except the edge and i did that on the sherline
05:29 PM Tom_L: as also the hole patterns
05:29 PM CaptHindsight: Li: are you looking for motos and drives or just drives for your motors?
05:29 PM Tom_L: i'm taking the big stuff out to my buds on his bridgport
05:29 PM Tom_L: if i ever get time
05:29 PM CaptHindsight: Tom_L: are you in touch with Stewart?
05:30 PM Tom_L: i know where his shop is
05:30 PM Tom_L: about 1.5 mi from me
05:30 PM CaptHindsight: i guess he changed locations
05:30 PM Tom_L: i know
05:30 PM Tom_L: they're both relatively close by
05:30 PM Tom_L: why?
05:31 PM Tom_L: i was over there part of one day in the old shop and he showed me around
05:31 PM CaptHindsight: is KimK still with him?
05:31 PM Tom_L: i don't know
05:31 PM CaptHindsight: just wondering
05:31 PM Tom_L: i suppose you could ask him, he's here sometimes
05:31 PM Tom_L: he's logged in anyway
05:32 PM Tom_L: i don't know how that all went down
05:33 PM Tom_L: Stuart has been logging in here more lately since he left MPM
05:33 PM CaptHindsight: is industrial space easy to find there?
05:33 PM Tom_L: yes
05:33 PM Tom_L: depends how much you need
05:33 PM CaptHindsight: 5-10k sq ft size
05:34 PM JT-Shop: nice steppers tom
05:34 PM Tom_L: i know there's a strip of smaller ones not too far away
05:34 PM Tom_L: dunno if they're occupied or not
05:34 PM Tom_L: some are i'm sure
05:35 PM Tom_L: JT-Shop, i just hope they're big enough to move this junk
05:35 PM JT-Shop: lol, look like some big ones for nema 23
05:35 PM Tom_L: yeah
05:35 PM JT-Shop: quad stack maybe
05:35 PM Tom_L: i'm not sure, at least triple
05:36 PM JT-Shop: why dual shaft?
05:36 PM Tom_L: because they were cheap
05:36 PM Tom_L: :)
05:36 PM JT-Shop: ok
05:36 PM Tom_L: it's not gonna be in the way or bother me
05:37 PM Tom_L: until i snag my shirt on one, then all hell'll break loose
05:37 PM JT-Shop: lol
05:38 PM JT-Shop: time for me to wander inside and check up on my Texas Red
05:38 PM Tom_L: man i really don't wanna dig thru that pendand but i sure need that switch working
05:38 PM Tom_L: *T
05:39 PM Tom_L: i could switch the logic and see if it's the io pin. that would be easy
06:15 PM ziper: i'm thinking about putting a duct on my outboard engine prop
06:16 PM ziper: if I bent a piece of stainless into the ring how could I make sure it was circular
06:18 PM Tom_L: bending a piece of stainless heavy enough will be a trick in itself
06:18 PM Tom_L: make a roll form for it
06:20 PM ziper: yeah I better make it out of cast aluminum
06:20 PM roycroft: for a boat?
06:21 PM ziper: yeah
06:22 PM roycroft: wouldn't it corrode in about a week and a half if it were aluminium?
06:22 PM ziper: naw
06:22 PM ziper: half the boat is aluminum, and the engine comes up when not in use
06:22 PM ziper: I can put a zinc on it
06:23 PM roycroft: you must only use the boat in fresh water
06:24 PM ziper: maybe make one out of pvc or whatever I can find in the right diameter to make sure it actually makes a difference
06:24 PM ziper: nope, saltwater
06:24 PM roycroft: how big does it have to be in diameter?
06:24 PM Tom_L: i'm guessing around 6-8"
06:24 PM roycroft: you can probably get a piece of ss tubing that size
06:24 PM roycroft: cut to length
06:25 PM roycroft: you might have to buy a foot of it and cut it off
06:25 PM ziper: 8.5 inches
06:26 PM roycroft: onlinemetals.com have 316 seamless in 6"
06:26 PM roycroft: 0.25" wall thickness though, and pretty pricey
06:28 PM ziper: might as well save my money for a bigger engine
06:28 PM ziper: i wish i had a lathe
06:28 PM Tom_L: save your money for that too
06:29 PM roycroft: i bet you could find a marine hardware store who have bronze or ss in 8.5"
06:29 PM ziper: for a pretty penny
06:29 PM Tom_L: now you're just gettin picky
06:30 PM roycroft: get some pvc and wrap silver duct tape around it
06:30 PM roycroft: it will look just like ss when it's underwater!
06:31 PM Tom_L: until he hits a log
06:32 PM ziper: special breakaway model)))))
06:33 PM roycroft: there used to be a tv show about loggers
06:33 PM roycroft: "axe men"
06:33 PM ziper: I had carb problems with the engine, somehow a fleck of crap got into the needle. filter must be old. I probably could have changed it on the water but didnt think of it
06:33 PM roycroft: there was some yahoo from lousiana on that show who recovered logs from the bayou
06:33 PM roycroft: he did horrible things to his boats
06:33 PM roycroft: which is probably why he had so many, and kept cycling through them
06:35 PM Tom_L: yeah the kid and dad didn't see eye to eye
07:04 PM roycroft: oh, that was the other guy
07:04 PM roycroft: the one who was screaming and yelling all the time (in anger)
07:04 PM roycroft: and his son screamed and yelled even more
07:04 PM roycroft: they were in florida
07:05 PM roycroft: i'm talking about the guy in louisiana who shot his gun off all the time and ate turtle soup every night
07:05 PM roycroft: the father and son were just incompetent
07:05 PM roycroft: the louisiana guy was a daredevil
08:28 PM roycroft: i took a couple pictures of the acrylic
08:29 PM roycroft: http://www.roycroft.us/Cracked1.jpeg
08:29 PM roycroft: http://www.roycroft.us/Cracked2.jpeg
08:29 PM roycroft: i can pull that corner right off and push it back on easily - there is really no pressure on the acrylic from the fastener
08:31 PM roycroft: oh, wait - that's not the corner i can remove
08:32 PM roycroft: it's too bad i tossed the original base piece - some of the cracks looked more like crazing than big clean cracks like this
08:34 PM roycroft: i did support the parts on parallels in a milling vise for locating and boring the holes
08:35 PM Tom_L: sometimes adding a sacrificial plate over and under will prevent chips outs
08:35 PM roycroft: i tried to only tighten the vise enough to keep the part from moving, but i wonder if that tiny amount of pressure caused some internal stress that resulted in microcracks while boring the holes
08:36 PM roycroft: there's a tiny amount of chipout on the larger holes
08:36 PM roycroft: i expected that
08:36 PM roycroft: i did not want to regrind a big s&d drill bit for plastic just for six holes
08:36 PM roycroft: and i don't mind that tiny amount of chipout
08:37 PM roycroft: it's where the corners cracked at the mounting holes that is my concern
08:38 PM roycroft: there could have been tiny chipouts as the drill exited the acrylic that caused the stress fractures, though
08:46 PM Rab: roycroft, you can see stresses in clear plastic under polarized light, for example the light from an LCD monitor. That might or might not be useful.
08:52 PM roycroft: hmm
08:52 PM roycroft: i have some polarizing sunglasses
08:52 PM roycroft: if i put them on and rotate the part i would probably be able to see those stresses
08:53 PM roycroft: i can see patterns in my side and rear car windows when i wear them
08:55 PM ziper: I could see the stresses in my polarized sunglasses during the sunset
09:24 PM roycroft: i suppose i should clamp the part in the vise and rotate my head to look for stresses
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