#linuxcnc Logs

Mar 08 2017

#linuxcnc Calendar

12:45 AM MacGalempsy: muah-hahaha
12:47 AM MacGalempsy: just when you thought it was safe to go back into the chat room
12:53 AM MacGalempsy: you thought wrong...
12:55 AM Wolf_: lol
12:56 AM Wolf_: now to figure out how much overkill these rails I have here are going to be for a laser cutter build
12:59 AM MacGalempsy: how big are the slides?
01:00 AM Wolf_: thk SR15 rails
01:02 AM Blaster is now known as Guest94025
01:03 AM Guest94025 is now known as Kurplink
01:03 AM archivist: too good for laser cutter!
01:03 AM * Kurplink says Howdee
01:03 AM Wolf_: lol, so much overkill eh?
01:04 AM MacGalempsy: nah
01:04 AM MacGalempsy: underkill, 32 would be overkill
01:05 AM MacGalempsy: hey hey Kurplink
01:05 AM MacGalempsy: sr 15 is 15mm or 1.5in?
01:05 AM Wolf_: seems I have 4 of them all 762mm/30” long
01:06 AM MacGalempsy: you going to run with belts or screws?
01:06 AM archivist: Wolf_, I started playing with the infrared on the renishaw LT02, I can switch it on by flashing the tarduino, the out put is too fast for slow optos, waiting for faster opto diodes to come
01:07 AM Cromaglious_: 30x30 with make for a nice laser
01:07 AM Cromaglious_: s/with/will/
01:07 AM Wolf_: well, i was thinking long axis of 60”/1500mm x 30”/760
01:07 AM Cromaglious_: even better!
01:07 AM Wolf_: M5-15mm steel core belt was my planning
01:08 AM Wolf_: archivist: cool stuff :)
01:08 AM Cromaglious_: I have gt2 on order
01:08 AM Kurplink: Imagine with me . I am building a machine Simple XYZ Gantry . I want to engrave 1/3 the circumference of various roundstock using a lathelike axis that can be removed from the bed of the XYZ mill. Would you describe this as an XYZ/sometimes XYZA machine?
01:08 AM Cromaglious_: got a bunch of nema 17's with belt pulleys
01:09 AM Wolf_: Kurplink: 4th axis for mills
01:10 AM Kurplink: Cool . Thanks Wolf_
01:10 AM archivist: Kurplink, XYZA machine is ok, you dont always have to run the 4th
01:11 AM Cromaglious_: I have 2 K40's have them opened up to 220mm x 325mm cut area which is still too tiny
01:11 AM Wolf_: hmm lol, I can’t find my data sheet for this older thk rail but I did find emc-1.0.0.scr.tgz
01:13 AM Wolf_: I started looking at the k40s, then the crappy red/black box 700x500
01:13 AM Wolf_: after some reading about both, I’m ordering a good tube and diy the box and frame
01:14 AM Kurplink: I have the conrtoller, drivers, power supplies, and nema34 motors. Going for some nice ballscrews for xyz doing a 3'x5'x2' mill. I'm running linuxcnc in a VM just to toy around and use the "simulated" machines. so xyza would be appropriate? or should I look at adding the 4th axis in config?
01:15 AM Wolf_: A=4th axis =)
01:15 AM Kurplink: look at adding the 4th axis in config of a 3axis machine that is.
01:15 AM Kurplink: coolio. Thanks Wolf_
01:16 AM Cromaglious_: the k40 usually swap the Y axis for the 4th... so you get X and A
01:16 AM Wolf_: lol
01:16 AM Wolf_: hmm
01:16 AM Wolf_: actually, thats kinda smart
01:18 AM MacGalempsy: anyone ever knurl with a file?
01:18 AM Wolf_: checkering a handgun count?
01:19 AM archivist: MacGalempsy, I did a knurl with the mill, nice and regular
01:19 AM MacGalempsy: let me get a pic of this
01:21 AM MacGalempsy: https://flic.kr/p/SyUkXF
01:21 AM MacGalempsy: Jan 1912
01:22 AM Wolf_: heh, neat idea
01:23 AM MacGalempsy: yeah. these old mags have all kinds of neat tricks
01:25 AM Wolf_: I’ll stick to using my lathe :)
01:29 AM Cromaglious_: Wolf: I'm with you there... knurling on the lathe is so much easier... checkering... I want my cnc to do that
01:30 AM Cromaglious_: the 24v on the k40 is really weak... you're better off putting in another 24v supply
01:31 AM Cromaglious_: what's another PS... already have a 12v and a 5v in there...
01:33 AM Wolf_: I’m building from full scratch, 24v15A psu, Azteeg X5 GT smoothie ware/LaserWeb, nema 23 steppers, 100w RECI tube, 100-130w psu
01:35 AM roycroft: knurling is a forming process, not a cutting process
01:35 AM roycroft: it cannot be done with a file
01:35 AM Wolf_: that pic, its using a file as a form die
01:36 AM * roycroft looks at the picture
01:36 AM roycroft: hmm
01:36 AM roycroft: that counts as knurling
01:36 AM roycroft: but it's kind of a strange way to do it
01:38 AM roycroft: clever, i suppose
01:39 AM Cromaglious_: Wolf_ you look at the JMC-machine.com integrated hybrid steppers? $100ish for a 1nm nema23 with build on driver and encoder. for closed loop operation
01:40 AM Cromaglious_: 142ozin ~ to a 1nm
01:40 AM Cromaglious_: morning Deejay
01:41 AM Deejay: moin
01:41 AM Wolf_: no, the X5 GT I ordered I had 4x TMC2660s added on it
01:41 AM Deejay: hi croma
01:41 AM Wolf_: so I can get away with $30/ea stepper motors
01:41 AM Cromaglious_: http://www.ebay.com/itm/NEMA23-1Nm-142oz-in-Integrated-Closed-Loop-Stepper-motor-36VDC-JMC-iHSS57-36-10-/262565303249?hash=item3d221c93d1:g:R~kAAOSwt7ZXpUbt
01:42 AM Cromaglious_: I'm going that route... I'm sick of no closed loop
01:42 AM Wolf_: not needed IMO
01:43 AM Wolf_: on a laser, you only lose steps due to speed
01:43 AM archivist: servo and do it properly
01:49 AM archivist: with "closed loop" steppers it is still open loop as far as linuxcnc "sees" therefore not a lot "better"
01:57 AM SpeedEvil: Losing 1 step is frighteningly close to losing a hundred in a row often
01:58 AM SpeedEvil: And - well - your closed loop stepper may in principle correct that, but not before you've got a crater
02:06 AM Blaster_ is now known as Kurplink
02:19 AM Cromaglious_: with the laser I'm ok open loop, on the mill I want closed loop, and if error gets to big there is an alarm...
02:19 AM Wolf_: true servo setup using mesa board IMO
02:20 AM Cromaglious_: you can hook it right into the estop circuit
02:20 AM Cromaglious_: I don't have that money...
02:21 AM archivist: but.... these closed loop steppers are not cheap
02:49 AM Cromaglious_: hmmm
03:06 AM Cromaglious_: nite all
03:10 AM Blaster is now known as Guest21622
04:50 AM XXCoder: cats. https://youtu.be/ZlPoPMbiffU
05:13 AM jthornton: big cats
05:17 AM XXCoder: yep
05:21 AM XXCoder: Cromaglious_: wow nice steppers
06:08 AM Deejay: re
08:11 AM JT-Shop: finally came up with a drilling speed feed spreadsheet that I like and is easy to use
11:52 AM lunada_ is now known as lunada
12:23 PM cpresser: pcw_home: I assume the 7i77 has +-15v (or +-12V) rails. how hard is it to access them?
12:24 PM cpresser: I need a few milliamps of each rail for a analog-addon i want to put in the control cabinet
12:46 PM enleth: slightly OT: have you ever seen original patterns for late 19th/early 20th century cast iron machine parts, or any details on how they were made? I'm thinking about those slender, slightly bulbous or sometimes T-beam-like shapes that seem to have dominated the cast iron designs back then
12:47 PM enleth: like https://chairish-prod.global.ssl.fastly.net/image/product/sized/1578c1df-0765-4894-a68f-c0a6b393b1c0?aspect=fit&width=640&height=640 or http://www.practicalmachinist.com/vb/attachments/f19/189342d1485200535-prentiss-tool-supply-co-drill-press-antique-vintage-machine5.jpg
12:48 PM enleth: archivist: I half-expect that you're going to know
12:48 PM _methods: what about them?
12:48 PM enleth: I'm curios what was used to create those shapes and join them
12:49 PM _methods: ah
12:49 PM skunkworks: wood? ;)
12:49 PM archivist: wooden patterns hand madde
12:50 PM skunkworks: http://bbs.homeshopmachinist.net/threads/73050-Setting-up-EMC2-on-PC/page2
12:53 PM enleth: they must have been literally carved out of raw wood like a sculpture, those shapes don't seem to be very conductive to any high-efficiency woodworking techniques at all
12:53 PM archivist: made of many parts nailed together
12:54 PM skunkworks: it was when form meant as much as function
12:54 PM enleth: I mean, they did have a lot of efficient tooling back then for cabinet making, but those castings look like they were designed and made by people who had very little to do with cabinet makers
12:54 PM archivist: some time(years) I scanned a pattern making section of a book http://www.collection.archivist.info/searchv13.php?searchstr=BK170
12:55 PM archivist: pattern making was a separate industry
01:01 PM archivist: and my built up pattern I made and the finished casting http://www.collection.archivist.info/archive/DJCPD/PD/2006/2006_05_02_Leawod/P4262333.JPG
01:01 PM archivist: yes I over did the scaling :)
01:04 PM roycroft: are you addicted to candy, archivist?
01:07 PM archivist: hooo me, no by the look of it cough sweets to the left, probably had a cold
01:17 PM CaptHindsight: http://www.northerntool.com/shop/tools/product_200320245_200320245 is the Drill Doctor worth buying?
01:17 PM CaptHindsight: plastic body, $100
01:18 PM enleth: CaptHindsight: I've got a similar cheapo drill grinder and it's just fine for regrinding dull or broken cheapo drills
01:18 PM archivist: if you want random sized holes after sharpening :)
01:18 PM enleth: but that's OK - you drill undersize with shit and finish with known good drills
01:19 PM enleth: as long as the shit drills quickly, it works
01:19 PM archivist: we used to tickle the edges to get the size we wanted
01:19 PM CaptHindsight: saves bits for hand drilling that arten't critical
01:19 PM roycroft: i have a drill doctor and it works decently
01:20 PM enleth: CaptHindsight: exactly
01:20 PM roycroft: it's easier to grind large drill bits by hand
01:20 PM enleth: yep, but for the small stuff you don't care much about, it's just convenient
01:21 PM enleth: BTW, some idiot at homeshopmachinist.net's hosting apparently blocked out my ISP
01:23 PM roycroft: i think the drill doctor was worth the money
01:24 PM roycroft: whenever i use a drill bit <3/8" or so in diameter and it starts getting dull i toss it in a bucket
01:24 PM roycroft: when i have a bunch in the bucket i pull out the drill doctor and spend a few minutes sharpening them
01:24 PM roycroft: it doesn't take long, and they're useful again after that
01:25 PM roycroft: but for 3/8" or larger bits i usually just go out to a grinder and touch them up when they get dull
01:26 PM roycroft: twist drills are not designed to drill accurate holes, so i don't really worry about perfect fixturing when sharpening them
01:27 PM enleth: actually you don't so much save money, because those drills are dirt cheap, but sometimes you do save a lot of time and cursing
01:27 PM enleth: when you find out that the only drills of the size you need are dull
01:27 PM enleth: and it's 3AM on a Sunday
01:28 PM roycroft: it saves some money
01:28 PM CaptHindsight: thats when tools tend to break
01:28 PM roycroft: more importantly it eliminates waste
01:28 PM enleth: sharpening a dud or two is faster than waiting a day to buy a new one
01:28 PM roycroft: reuse is more efficient than recycling
01:28 PM enleth: well, yes, it's just not a lot of money
01:28 PM enleth: or actually, it is a lot of money if you add in the cost of your time needed to get new drills
01:29 PM roycroft: the drill doctor lets one alter the included angle btw
01:29 PM roycroft: as well as allowing one to do split-point grinding
01:29 PM roycroft: so it's fairly flexible in its capabilities
01:29 PM CaptHindsight: how do you guys start your deep small holes in aluminum? <3/8"
01:30 PM roycroft: with a spot drill, just like in any other material
01:30 PM enleth: roycroft: oh, that's nice, my sharpener just grinds 118deg, no split
01:30 PM roycroft: unless it's a really tiny hole
01:30 PM CaptHindsight: spot drill or small end mill hole first?
01:30 PM enleth: er, 111deg, not 118
01:32 PM enleth: CaptHindsight: I use a center drill, then start with a 3mm (~1/8in), then it depends on how deep and what diameter it's going to be
01:32 PM roycroft: i used to use center drills to start holes, but now i use spot drills
01:32 PM roycroft: center drills are not the correct angle
01:32 PM roycroft: they're good for drilling holes for locating centers on lathes
01:33 PM roycroft: but not for starting holes for other drills
01:34 PM enleth: I'm not going to disagree, but if you don't have those, a center drill is still better than a regular one chucked jaws against the flutes
01:34 PM roycroft: yes
01:34 PM roycroft: in a pinch a center drill is better than nothing
01:35 PM roycroft: besides, center drills live by the lathe
01:35 PM roycroft: spot drills live by the mill
01:35 PM roycroft: i can't be bothered to walk across the room :)
01:35 PM enleth: especially if you happen to have a big center drill that has the starter nub of the same diameter as your next drill
01:35 PM enleth: then you're not really depending on the angle it cuts with the tapered shoulder
01:35 PM enleth: because you don't let it cut
01:36 PM enleth: I think the angle on the very tip is not 111 or 118deg either on them, but at that point you have a fully formed starting hole made
01:37 PM enleth: I've got some 8mm center drills with a slightly undersize 3mm starter which makes nice starting holes for 3mm twist drills
01:38 PM enleth: the twist drill is an almost-press-fit into the hole
01:53 PM JT-Shop: yea my sheet of polycarbonate is here
02:19 PM skunkworks: heh - he deleted his post
02:19 PM skunkworks: oops
02:20 PM JT-Shop: who did?
02:21 PM skunkworks: on home shop machinist someone was asking about linuxcnc
02:21 PM JT-Shop: oh
02:21 PM skunkworks: he came back this morning and said that in a few weeks centroid is going to have a hobby solution for 200-400$
02:22 PM skunkworks: someone private messaged him..
02:22 PM skunkworks: that post disappeared.
02:22 PM skunkworks: So I replied - good luck - let us know how it goes... But it doesn't make sense because he deleted the post I was wishing him good luck to
02:25 PM JT-Shop: that a big change from $15k-$25 to $200-$400
02:26 PM JT-Shop: Rigid tapping is $550 extra...
02:27 PM * JT-Shop quits looking on the centroid page and goes back to work
02:28 PM JT-Shop: well I don't have to worry about tapping the polycarbonate sheet now Makrolon and other type don't like sharp edges
02:32 PM CaptHindsight: their MPG is $495 http://www.centroidcnc.com/cnc_technology.html
02:36 PM jdh: I need a nema23 size 3ph servo with encoder and 50:1 gearbox. any suggestions for vendor/model?
02:36 PM Cromaglious_: centroid cnc ain't cheap!
02:37 PM CaptHindsight: jdh: new or used?
02:37 PM Cromaglious_: how fast does it needto be?
02:37 PM CaptHindsight: ~200W?
02:38 PM CaptHindsight: Grizzly sold this cnc mill with centroid for ~$25k http://www.grizzly.com/outlet/9-X-49-3-Axis-CNC-Milling-Machine/G0498
02:38 PM jdh: new. not speedy.
02:38 PM jdh: 200w is fine, could do less
02:39 PM CaptHindsight: and it looks like they would charge extra for coordinate system rotation and rigid tapping
02:39 PM Cromaglious_: does it absolutely need to be a servo?
02:39 PM CaptHindsight: jdh: in stock or can you wait 4-6 weeks?
02:39 PM jdh: replacing reliance electrocraft e-3622-h-f00an
02:40 PM jdh: could wait. none are currently dead
02:40 PM jdh: I have 20 or so and they are discontinued
02:41 PM CaptHindsight: https://www.automationdirect.com/adc/Shopping/Catalog/Power_Transmission_(Mechanical)/Precision_Gearboxes_for_Small_NEMA_Motors/NEMA_23_Frame for just the gearbox
02:42 PM Cromaglious_: ebay has a bunch listed not so sure about the gear box
02:43 PM CaptHindsight: yeah but he wants new ones, unless you see any new there
02:44 PM jdh: we can't buy off ebay
02:44 PM CaptHindsight: jdh: I've never gone wrong with Parker
02:44 PM Cromaglious_: $2000ish http://www.ebay.com/itm/New-E-3622-H-F00AN-3622-00-952-Reliance-Servo-Motor-Brushless-with-encoder-/401161481072
02:45 PM Cromaglious_: http://www.dsmachine.com/index.html I think this is them
02:45 PM jdh: parker is usually painful unless you have a parker drive
02:46 PM CaptHindsight: for connections or tuning? I have more problems with finding matching or swapping connectors
02:48 PM jdh: connections
02:49 PM jdh: they are perfect with parker drives
02:49 PM jdh: these use amc
02:50 PM CaptHindsight: I mix and match with AB
02:53 PM Cromaglious_: ugh... so used to having single core cpu's... compiling kernel is much better with make -j<# cores - 1>
02:55 PM jdh: pretty sure these have 50k count encoders also
02:55 PM Cromaglious_: there we go.. loadavg now at 3.63
02:55 PM CaptHindsight: jdh https://www.automationdirect.com/adc/Shopping/Catalog/Motion_Control/Servo_Systems/Low_Inertia_(100W_-_1KW)_Servo_Systems/200W_Servo_System_(Low_Inertia)/SVL-202 out of stock and I've never used them
02:58 PM CaptHindsight: jdh: with 50:1 are you accurate to 0.5 arc seconds?
02:58 PM jdh: existing ones have hall sensors also
02:59 PM jdh: heh. I run them until they stall. no accuracy really
02:59 PM CaptHindsight: try Yaskawa as well
03:00 PM jdh: need a drop in replacement for maintenance guys to handle
03:01 PM CaptHindsight: jdh: what control/drive is used?
03:02 PM jdh: relabled amc 8amp brushless drive. delta tau pmac controller
03:02 PM jdh: encoders go to pmac only
03:04 PM jdh: those matching drives are cheap though
03:07 PM Cromaglious_: hmmm PreemptRT kernel image for raspberry pi 3
03:10 PM CaptHindsight: jdh: I have had issues with AMC drives
03:10 PM CaptHindsight: haven't used them for a while
03:10 PM jdh: we lose one every other year or so.
03:11 PM jdh: could be due to our maint guys though
03:14 PM Cromaglious_: job security man!
03:15 PM CaptHindsight: pcw_home: is there any way to have more than 1 field IO voltage present on a 7i77 without getting out a razor blade and soldering iron?
03:16 PM CaptHindsight: checking before I use a few level translators
03:21 PM JT-Shop: jdh: these are pretty neat http://www.fpeautomation.com/productpage.php?mfrid=28
03:22 PM JT-Shop: you can get them with build in drive and plc
03:23 PM Deejay: re
03:24 PM jdh: JT: I actually have their sales slick in my desk
03:24 PM JT-Shop: I've played with them before
03:24 PM jdh: but, can't really change these easily
03:24 PM JT-Shop: due to size limits?
03:25 PM jdh: this application has the pmac controller in thw backplane with the plc
03:25 PM JT-Shop: ah
03:25 PM jdh: all plc io with controller is via shared mem
03:26 PM jdh: nice idea, overly complicated, hard to change
03:26 PM pcw_mesa: CaptHindsight, no (if you want spilt I/O voltage, a 7I8 is a better choice)
03:26 PM jdh: my other similar system just uses brushed dc drives and discrete io
03:26 PM pcw_mesa: 7I84
03:28 PM jdh: 50k counts are from my failing memory. weird number
03:29 PM CaptHindsight: pcw_mesa: can a I toggle an IO as fast as 25KHz with the 7i84?
03:29 PM pcw_mesa: CaptHindsight: you can also use spare encoder pins for TTL inputs
03:29 PM jdh: code uses encoder/3072 for some reason
03:29 PM pcw_mesa: No, 7I84 is servo thread only
03:30 PM pcw_mesa: (serially connected to host)
03:30 PM CaptHindsight: pcw_mesa: I have 3-4 5V TTL inputs and 2 TTL outs where one out is PWM up to 25KHz
03:31 PM CaptHindsight: using the 7i77 for the 4 servos
03:31 PM pcw_mesa: so you have 6 spare TTL inputs (encoders 4 and 5)
03:33 PM CaptHindsight: I could use a LPT port to control two more steppers and 2 TTL out
03:33 PM CaptHindsight: pcw_mesa: what's the max speed of the outputs on the 7i77?
03:34 PM CaptHindsight: I could level shift 24V to 5V
03:34 PM pcw_mesa: Field outputs?
03:34 PM CaptHindsight: pcw_mesa: yes
03:34 PM pcw_mesa: usually 500 Hz (servo thread/2)
03:35 PM pcw_mesa: if you want PWM you could use the RS422 expansion port XMIT data
03:35 PM pcw_mesa: (or just use the other 5I25/6I25 port for TTL I/O/PWM/ whatever)
03:35 PM CaptHindsight: pcw_mesa: is 7i42 an option since I have a 6i25?
03:36 PM CaptHindsight: yeah ok
03:36 PM pcw_mesa: 7I75
03:36 PM pcw_mesa: (thats the DB25 equiv of the 7I42TA)
03:37 PM CaptHindsight: I also have 7i92's
03:37 PM pcw_mesa: same story as 5I25/6I25
03:39 PM CaptHindsight: well one ethernet cable between PC and machine vs 2-3 LPT cables
03:40 PM CaptHindsight: hmm maybe use the 7i75 to drive a stepper or two
03:41 PM CaptHindsight: pcw_mesa: thanks
03:57 PM CaptHindsight: ouch 7i75 is out of stock :(
03:58 PM CaptHindsight: oh noes so is the 7i42TA
03:59 PM JT-Shop: hmm the 7i75 is one of the very few cards I don't stock :(
04:00 PM CaptHindsight: JT-Shop: was just checking your site for both
04:04 PM CaptHindsight: well maybe 500hz is good enough for this application
04:05 PM CaptHindsight: I doubt anyone will even need 0.2% precision for power output
04:23 PM Deejay: gn8
04:38 PM Cromaglious_: hmmm ethernet on arduino uno/nano talking to linuxcnc
04:43 PM Cromaglious_: https://forum.linuxcnc.org/24-hal-components/28745-io-interface-with-arduino-over-ethernet
04:45 PM Cromaglious_: wooo use pin 3 for pwm
05:13 PM JT-Shop: CaptHindsight: thanks for checking
05:32 PM jasen_: hi all , any idea why i cant find the sources of xemc
05:32 PM JT-Shop: what is xemc?
05:34 PM jasen_: c++ GUI
05:34 PM jasen_: it was availabe thill 2.5
05:35 PM cradek: are you looking in one of the old branches?
05:36 PM jasen_: my old gui is saing that cannot connect with the emc
05:37 PM jasen_: probably there are some changes since 2.5
05:37 PM jasen_: and I am trying to see them
05:37 PM jasen_: linux/EMCusage.cxx 413: can't establish communication with emc linux/EMCusage.cxx 579: emcError buffer not available
05:38 PM jasen_: this is what is coming out
05:39 PM cradek: g28
05:39 PM cradek: heh oops
05:41 PM cradek: kind of in crystal ball territory here. if you want to see changes between version 2.5 and master in linuxcnc I can tell you how to do that with git: gitk v2.5_branch..master
05:41 PM cradek: to see only changes that affect the src/emc/usr_intf directory: gitk v2.5_branch..master -- src/emc/usr_intf
05:43 PM jasen_: xemc was verry usefull for that. it was readble and simple to undurstand haw to make the thinks . it miss me.
05:44 PM cradek: you might consider halui as a replacement for study - it's even simpler, with no gui stuff
05:44 PM cradek: src/emc/usr_intf/halui.cc
05:46 PM jasen_: no pithon
05:46 PM jasen_: aaa , thanks
07:29 PM andypugh: Any cyclists here? Some really crazy old gearing systems here: http://www.bikeraceinfo.com/photo-galleries/derailleurs-1.html
07:30 PM roycroft: back in another life i used to cycle competetively
07:30 PM roycroft: that was a long, long time ago though
07:30 PM roycroft: not that long ago, however
07:31 PM andypugh: The Campag system with a rack formed into the dropout is actually genius :-)
07:44 PM cradek: wow, those are neat
07:45 PM andypugh: I could really fancy having a go with a bike with that system.
07:45 PM cradek: I expected to see the retro-direct
07:46 PM cradek: (I really want to try one)
07:47 PM andypugh: I also found out, after seeing that, that you can still buy wooden wheel rims, and they are apparently not awful: https://cyclingtips.com/2010/04/is-wood-the-goods/
07:47 PM andypugh: retro-direct? Linky?
07:48 PM cradek: https://en.wikipedia.org/wiki/Retro-direct
07:48 PM cradek: I only happen to know about it because a friend of a friend rides (a homemade) one
07:48 PM andypugh: My dad has a 1950s rudge with a 4-speed derraieur. I should unearth it (I know which of hos piles of scrap it is under) and see if I can get it working.
07:50 PM andypugh: I wonder if backwards pedalling is more or less efficient?
07:50 PM andypugh: I can almost imagine that on a TT bike you could get a better aero position pedalling backwards.
07:53 PM pcw_mesa: My brother has a Alenax and should win an award for being terrible to ride
08:00 PM andypugh: <google> Ah! I invented a similar (but linear) system for recumbents, but spotted the problems and pointlessness before making one :-)
08:02 PM * zeeshan is pulling hairs
08:02 PM zeeshan: im involved with a bunch of allen bradley control stuff
08:02 PM zeeshan: am i weird to find all this new stuff unnecessary?!?!
08:02 PM zeeshan: theres a frigging input module, output module
08:02 PM zeeshan: all connected with ethernet
08:03 PM zeeshan: kinetix drives, 755 ac drive
08:03 PM zeeshan: all ethernet
08:03 PM zeeshan: ip addresses
08:03 PM zeeshan: what happened to the good old days of analog cables
08:03 PM malcom2073: analog is way too prone to noise
08:03 PM malcom2073: :-P
08:04 PM zeeshan: yea i guess in factory settings
08:04 PM zeeshan: with long cable runs
08:04 PM zeeshan: i do like the backplane expansion feature for adding axis
08:04 PM zeeshan: i was looking at the control stuff for the factory we built
08:04 PM zeeshan: its literally like 10 zones
08:05 PM zeeshan: with sub controllers that control like 329021390238 axis
08:05 PM zeeshan: everything is communicating
08:05 PM zeeshan: its nuts
08:05 PM malcom2073: Dude, all those how-it's-made factories?
08:05 PM zeeshan: i wouldnt even know where to begin if crap went wrong
08:05 PM malcom2073: They're CRAZY messes of networking, wiring, conrols
08:05 PM malcom2073: There's a reason why robotics technician is a 6 figure job
08:06 PM malcom2073: That an automation engineering
08:06 PM zeeshan: at our place it's mostly the EE's doing the control stuff
08:07 PM zeeshan: i kind of want to learn this new stuff
08:07 PM zeeshan: there is this thing called cip motion
08:07 PM zeeshan: which apparently converts a regular ethernet port
08:07 PM zeeshan: to allow real time communication
08:08 PM malcom2073: We use ethercat for that mostly over ethernet
08:08 PM zeeshan: i dunno wtf the difference is man
08:08 PM zeeshan: lol
08:08 PM zeeshan: theyre all ethernet!
08:08 PM malcom2073: Different bits in different order
08:08 PM malcom2073: OSI layers man!
08:08 PM zeeshan: The network must be able to support 100 axes with a 1ms update rate; Position loops must be closable at a time base of less than 125 uS; Any axis can be either a variable frequency or servo drive with full networked configuration; It must be possible to synchronize discrete signals with a motion axis; and I/O, video and voice traffic must be carried on the same Ethernet as motion traffic.
08:08 PM malcom2073: It's not ethernet
08:08 PM zeeshan: i find this a bit nuts
08:09 PM zeeshan: i kinda saw what andy has been doing with is vfd
08:09 PM zeeshan: in a factory setting
08:10 PM zeeshan: we are using a vfd along with an encoder for positioning things
08:10 PM zeeshan: there is a brake tho to keep things in place when the positioning is done
08:10 PM zeeshan: i thought this was some voodoo thing that people say "bad stuff"
08:10 PM zeeshan: cause of slip etc
08:11 PM malcom2073: It's amazing how tight a motor will hold when you electrically brake it
08:11 PM zeeshan: all i know is we're holding 1 thou tolerance no problem
08:11 PM malcom2073: a permanent magnet motor*
08:11 PM zeeshan: yes
08:12 PM cradek: my car also holds position to 1 thou while parked
08:12 PM zeeshan: now im encouraged to add C axis to my lathe
08:12 PM zeeshan: since it alreadyt has a mechanical brake
08:12 PM zeeshan: cradek lies
08:13 PM zeeshan: i hope its as simple as using the encoder input back into the vfd
08:13 PM zeeshan: or linuxcnc
08:13 PM zeeshan: and controlling velocity
08:13 PM zeeshan: then asking linuxcnc to go to an angle because i would have fairly accurate velocity control
08:14 PM zeeshan: velocity profile i mean
08:14 PM Crom: wooo this is really interesting.... https://forum.linuxcnc.org/24-hal-components/28745-io-interface-with-arduino-over-ethernet
08:14 PM malcom2073: I imagine a VFD + encoder can be treated as a velocity servo yeah?
08:14 PM zeeshan: then turn on brake!
08:14 PM zeeshan: yes
08:14 PM Crom: he's using an Uno... looking at modding it to use a Mega
08:14 PM Crom: malcom2073, yep
09:00 PM CaptHindsight: crap, anyone know the part number for the spindle seal on a matsuura 710? :) just started dripping
09:01 PM malcom2073: 0IC-U812
09:03 PM CaptHindsight: I have to change the bearings anyway but didn't want to right now
09:13 PM andypugh: CaptHindsight: Just switch to neat oil as the cutting fluid and ignore the leaks/
09:19 PM andypugh: OK, time to stop.
09:21 PM Crom: Ethernet interface on the cheap yay! 13 pwm pins 11 pins which could be either in or out, 16 analog in. pins for step and dir for XYZABCD
09:22 PM Crom: s/ 16 analog in. pins/ 16 analog in. and digital out pins/
09:39 PM CaptHindsight: http://www.ebay.com/itm/Matsuura-Vertical-Machining-Center-/401191635743 $500
09:40 PM CaptHindsight: Phoenix, Arizona
09:58 PM os1r1s: Can anyone answer a quick fixturing question? I want to cut a profile path on a 1" x 2" x2" piece of 6061. I'd like to screw it down with two 5mm screws and cut around them. Do you think that would be sufficient to hold them?
10:03 PM Crom: 5mm 0.8 pitch 8.8 bolt is 11345 ultimate strength in newtons
10:04 PM CaptHindsight: os1r1s: yes
10:05 PM Crom: 2500 #'s with 2 screws your looking at over 4000 lbs before you think about stretch
10:05 PM CaptHindsight: os1r1s: I've been cutting parts that size all week
10:05 PM os1r1s: CaptHindsight Ok. That's awesome.
10:05 PM Jymmm: CaptHindsight: cuting the cheese that size just aint the same thing, mkay
10:05 PM os1r1s: CaptHindsight You are using a fixture for it?
10:06 PM Crom: os1r1s, bookmark this one http://www.tech.plymouth.ac.uk/sme/desnotes/boltb.htm
10:06 PM CaptHindsight: heh, I'm using 1/4-20 and 5/16-18 screws to hold them and its overkill
10:07 PM os1r1s: Crom I guess I'm more worried about them working loose or not providing the right level of rigidity
10:07 PM CaptHindsight: os1r1s: I use m4-0.7 in the final assembly
10:08 PM CaptHindsight: they aren't going anywhere
10:08 PM Crom: 2500#'s of clamp in 2 places... it won't even think about moving
10:08 PM os1r1s: CaptHindsight Got a picture of the fixturing? I'm curious
10:08 PM CaptHindsight: nope, teking it apart since the spindel is currently leaking oil
10:11 PM Crom: on the way home...
10:18 PM roycroft: i may have found a lathe again
10:18 PM roycroft: it was posted an hour ago, and i'm the second caller
10:18 PM roycroft: i'm arranging to take the day off work if necessary tomorrow to go get it
10:19 PM roycroft: it's in central oregon, over the mountains, but the passes should be in good shape tomorrow - above freezing
10:20 PM roycroft: a 12x36, which is exactly the size i want
10:20 PM roycroft: and the swing is actually 13", not 12", although the model designation is 12x36
10:21 PM * roycroft would prefer to have been the first caller, but second caller is better than >2nd caller
10:37 PM SpeedEvil: roycroft: good luck
10:42 PM roycroft: thanks
10:42 PM roycroft: weather looks ok - heavy rain, but no snow in the passes
10:42 PM roycroft: i'm finding that there are more ok deals on machinery around here than i thought, but a person needs to jump on them immediately
10:43 PM roycroft: it's chinese, but his price is $1100
10:43 PM roycroft: and i would love to get one for that price
10:56 PM roycroft: excellent - i've arranged to take the rest of the day off work if the deal goes through
11:28 PM Cromaglious_: nice price$
11:29 PM Cromaglious_: I could sell my 1945 sheldon 10" for that
11:36 PM Cromaglious_: engine hoist and trailer just case?
11:55 PM roycroft: i would probably buy your '45 sheldon for that
11:56 PM roycroft: if it were close
11:56 PM roycroft: i don't have a trailer
11:56 PM roycroft: i have a cherry picker, but i would not be able to fit it and the lathe in my pickup
11:56 PM roycroft: the seller has a cherry picker though
11:56 PM roycroft: and said he can help load
11:57 PM roycroft: this machine is an asian import for that price, of course
11:57 PM roycroft: ~10 years old the guy said
11:57 PM roycroft: but for $1100 i don't mind getting a kit