#linuxcnc Logs

Feb 24 2021

#linuxcnc Calendar

12:36 AM roycroft: on a remotely related note, i watched a video lately where a guy made a nut and bolt that screwed on both clockwise and counterclockwise
12:43 AM roycroft: and unscrewed both ways as well, of course
12:43 AM XXCoder: roy I own on
12:43 AM XXCoder: *one
12:43 AM XXCoder: i 3d printed it.
12:43 AM XXCoder: i plan to 3d print hand drill one later
12:43 AM XXCoder: https://www.thingiverse.com/thing:4740760
12:43 AM roycroft: it is rather clever
12:43 AM roycroft: not too stong though, i should think
01:07 AM Deejay: moin
01:32 AM MrSunshine: or does one need a motion control card for that ?
01:35 AM XXCoder: i remember that mesa does general signals on its own
01:36 AM XXCoder: but driving stuff directly it needs drivers
01:36 AM XXCoder: jt knows a lot more
01:37 AM MrSunshine: would be nice to get rid of the computer part in the equation .. being able to run on a more powerfull computer that has alot crappier realtime performance =)
01:38 AM MrSunshine: that sentance felt strange :P
01:38 AM MrSunshine: seems that card is compatible with standard bob cards also, so no modification to the electronics required =)
01:48 AM MrSunshine: anyone know if there is a source of mesa cards in europe ?
01:54 AM MrSunshine: the shipping for mesa costs more than double the price of the card :P
01:54 AM XXCoder: ow
01:56 AM MrSunshine: 190$ ... card is 89$ ...
01:56 AM MrSunshine: thats nice :P
01:58 AM enleth: ugh, it wasn't as bad a few years ago
02:00 AM MrSunshine: found eursurplus.com .. dont know what that is =)
02:00 AM MrSunshine: they have mesa cards, and wine ...
02:00 AM MrSunshine: :P
02:02 AM XXCoder: if its ripoff site, you might need wine to soothe your head
02:02 AM XXCoder: ;)
02:04 AM MrSunshine: ah they are on mesas list of distributers .. seems like there is alot more of them also =)
02:04 AM XXCoder: nice
02:04 AM enleth: MrSunshine: regarding offloading, no, the standard "firmware" does not do motion control by itself, main CPU still does that
02:06 AM XXCoder: enleth: effecively, lcnc sends commands to mesa, mesa generates signals to drivers right?
02:06 AM enleth: the hardware could do it, it could be done (VHDL source code is available from Mesa) and this was brought up a few times in the linuxcnc development community
02:06 AM XXCoder: ie it offloads generatipn of signals so it is far less affected by latency
02:07 AM MrSunshine: enleth, but it has hw stepgen ? shouldnt that offload so for example following errors should disapear?
02:07 AM enleth: but the problem is, a part of linuxcnc would have to be reimplemented in VHDL, and then maintained in parallel with feature parity, etc.
02:08 AM enleth: MrSunshine: frankly, I'm not sure about step outputs, all I have and use are servos
02:08 AM MrSunshine: as my machine can do alot higher speeds than the computer can put out =)
02:08 AM enleth: I think stepgen is, indeed, handled by mesa, but don't quote me on that
02:08 AM XXCoder: jt will be here evenualluy
02:09 AM enleth: MrSunshine: for one, you're not abusing a parallel port that was never meant to pulse at a high rate
02:35 AM CaptHindsight: if you want low cost a CNC that works like an easy bake oven the most people use GRBL on a duino or some Chinese CNC controller
02:36 AM CaptHindsight: most people have tooling that easily costs many times the price of a PC and Mesa card
02:38 AM CaptHindsight: MrSunshine: have you looked at the #reprap CNC controllers like the duinos and smoothie?
02:38 AM CaptHindsight: they leave out the GUI and focus on simple stepper systems at low low prices
02:38 AM XXCoder: low, low ability too
02:40 AM XXCoder: I LOVE that panel lift thing https://youtu.be/0rVbtdf66wU
02:40 AM XXCoder: I want one heh
02:41 AM CaptHindsight: sorry meant most LinuxCNC users have tooling that easily costs many times the price of a PC and Mesa card
02:43 AM MrSunshine: CaptHindsight, dont care about low low prices realy .. i have a big router that needs to be run without hickups like random join following errors cause i started the spindle and started moving the machine while it was ramping up ...
02:45 AM MrSunshine: most of the time it runs fine but this was a stupid error that offset the whole machine over 10mm, so looking into making home volatile to the join following errors now and try and update step/dir stuff so its not so dependant on the computer that runs it
02:49 AM CaptHindsight: MrSunshine: are you using servos?
02:49 AM CaptHindsight: maybe you mentioned in the backlog I haven't seen yet
02:51 AM veegee: https://www.amazon.ca/Fluke-TP2-Slim-Reach-Stainless-Diameter/dp/B000LDJX6I
02:51 AM veegee: Ugh so expensive
02:51 AM veegee: but no one else makes modular stainless steel probes
02:54 AM veegee: oh what the hell I just realize the TP2 is identical to the TP220 if you just take off the rubber grip...
02:59 AM MrSunshine: CaptHindsight, closed loop steppers
03:00 AM MrSunshine: does not send any encoder signals to linuxcnc tho
03:04 AM veegee: MrSunshine is resonance really an issue with steppers?
03:05 AM veegee: I forgot the issue, mid band instability is it?
03:06 AM MrSunshine: resonance ? the problem i had was that i get join following error if i start the spindle then start moving the machine at the same time =)
03:06 AM MrSunshine: also, low speeds due to huge jitter in the computer
03:06 AM MrSunshine: so wanted to offload the computer to make it less sensetive to the jitter
04:06 AM htasta: how much jitter? did you try fixing it already? (disable HT etc)
04:18 AM Tom_L: morning
04:18 AM XXCoder: dead. https://www.frys.com/
04:18 AM XXCoder: hey tom
04:57 AM JT-Cave: morning
04:57 AM XXCoder: yo
04:57 AM XXCoder: mesa card does the signaling to drivers right?
04:58 AM XXCoder: pc commands mesa what to do and mesa manages it?
04:58 AM JT-Cave: aye
04:58 AM XXCoder: glad I remembered right then
04:58 AM XXCoder: sady mrsunshine is out
05:18 AM MrSunshine: XXCoder, nope im here ... dont understand why it keeps disconnecting :/
05:19 AM MrSunshine: getting different usernames and the channel is locked =)
05:20 AM MrSunshine: JT-Cave, so a 7i92 for example that takes signals over ethernet and drives an ordenary breakoutboard shouldnt be affected by jitter in the computer ? =)
05:22 AM MrSunshine: im aparently on linuxcnc-dev on my cnc computer .. how can i see version info (not at the router now .. connected over ssh)
05:25 AM JT-Cave: a 7i92 can work with up to 100 us of jitter
05:25 AM JT-Cave: test your pc with latency-histogram --nobase
05:33 AM MrSunshine: got a result of 11500 from the jitter test thingie before (looong time since i did this, read it in the ini file) =)
05:34 AM MrSunshine: any hal wizard here ? =) i would like to have a button for "spindle warmup" that turns on the spindle and runs it at a given rpm .. is that possible to do with just hal and pyvcp ? =)
05:41 AM MrSunshine: or thourhgt some gcode but need to call it somehow =)
05:50 AM htasta: yeah should be fairly simple to do. M3 S5000 to run it at 5krpm f.e. you can also use G4 to time how long you wanna do it if you want to run it at 5k then 7.5k then 10k etc.
05:50 AM MrSunshine: yeah but how do i call it from pyvcp ? =)
05:51 AM htasta: you mean make a button in the UI?
05:51 AM MrSunshine: button is there =)
05:52 AM htasta: http://wiki.linuxcnc.org/cgi-bin/wiki.pl?Adding_Custom_MDI_Buttons
05:53 AM MrSunshine: yes! that looks like it tells me all i need to know =)
05:53 AM htasta: :D
06:02 AM JT-Cave: lol that's my page
06:05 AM MrSunshine: there, hopefully added an ampmeter to my axis and the spindle warmup button .. will be fun to try and restart linuxcnc now :P
06:06 AM MrSunshine: JT-Cave, how is speed using for example that card compared to a parport ?
06:07 AM MrSunshine: as my motors can drive my machine alot faster but the computer with parport cant follow atm =)
06:08 AM JT-Cave: the card can send step pulses faster than your drive can accept them
06:22 AM MrSunshine: ok so no more bottleneck on that side of it then atleast =)
06:26 AM JT-Cave: well there is more than one jitter test thingy so I suggest you run the one above
06:31 AM MrSunshine: aight will do it when i go out to the workshop to test my config modifications =)
09:44 AM roycroft: my county has finally moved from extreme to high risk
09:44 AM XXCoder: yay
09:47 AM roycroft: yeah, but i hope folks don't go crazy
09:48 AM roycroft: the south african mutant has been confirmed in washington state, and i'm sure it's just a matter of time (probably not too much) before it shows up here in oregon
09:48 AM roycroft: there's a good chance that will cause another small spike
09:49 AM roycroft: but it's still good news
09:49 AM XXCoder: yeah graph of new cases have been sloping down for while now
09:49 AM XXCoder: my mom just finally got vaccine #1
09:58 AM JT-Shop: well I think my quart of T&T Varnish Oil is on the way again
10:00 AM roycroft: excellent
10:00 AM roycroft: to both
10:00 AM roycroft: my chisels are days overdue now :(
10:01 AM roycroft: the whole concept is irritating
10:01 AM roycroft: they are made in hood river oregon
10:01 AM roycroft: then shipped to ohio for final distribution
10:01 AM roycroft: and i don't understand why
10:01 AM roycroft: they're a small shop, and everything is made to order
10:01 AM roycroft: one would think they would be able to ship directly
10:02 AM roycroft: i've alreay been waiting since last year for them
10:46 AM ziper: how much does introducing mass help improve rigidity of a machine?
10:47 AM ziper: something like a cast slab of concrete placed under the chip tray of a lathe?
10:50 AM roycroft: i don't know how to accurately quantify that, but i can say "a lot"
10:54 AM ziper: me neither, hence the vague question
10:57 AM CaptHindsight: ziper: it's about the mass in the right location
10:57 AM CaptHindsight: and the type of mass, how does it dampen vibrations
10:57 AM ziper: yes, that is kind of what I was thinking. if the ways aren't heavy/stiff enough, it doesn't matter if you bolt it to a bolder
10:58 AM CaptHindsight: 500 kg of jello vs 500kg of epoxy granite 1:9
10:58 AM CaptHindsight: https://my.mech.utah.edu/~me7960/lectures/Topic14-DesignOfMachineStructures.pdf
10:59 AM CaptHindsight: https://my.mech.utah.edu/~bamberg/research/PrinciplesOfRapidMachineDesign/Principles%20of%20Rapid%20Machine%20Design.pdf
10:59 AM CaptHindsight: yeah Utah :)
10:59 AM ziper: thanks
11:03 AM htasta: Do Or Do Not - There Is No Try Yoda
11:03 AM htasta: from the paper, hahaha
11:13 AM roycroft: what capthindsight is part of why i can't quantify it
11:13 AM roycroft: it has to be the right mass in the right place
11:21 AM ziper: wow
11:21 AM ziper: https://www.instructables.com/CNC-Milling-a-Boat-Propeller-in-Only-3-Axes/
11:21 AM ziper: there is an instructables for everything
11:23 AM ziper: but a bit of a copout from the design, since blades often do overlap
11:53 AM veegee: So officially, anything less than grade 80 chain can't be used for "overhead lifting"
11:53 AM veegee: What about lifting not overhead
11:54 AM veegee: Like using a grade 70 transport chain to lift an engine out of a car for example
11:56 AM roycroft: "overhead" is kind of an ambiguous term anyway, isn't it?
11:56 AM roycroft: say you want to lift something 170cm high
11:57 AM roycroft: if you're 166cm tall that's "overhead"
11:57 AM roycroft: if you're 190 cm tall it's not
11:58 AM roycroft: do tall people need different grade lifting chains that short people?
11:58 AM veegee: yeah that's what I'm getting at
11:58 AM veegee: anyway doesn't matter for me, all my chains are grade 100
12:00 PM veegee: What are these types of "sprocket" called? https://www.accomhs.com/wp-content/uploads/2019/05/Load-Sheave-Chain-Guide-675x500.jpg?x98305
12:00 PM veegee: It's not the same type of sprocket for a bicycle or motorcycle chain
12:02 PM veegee: Oh how lucky, that specific image has it in its filename: load sheave
12:06 PM * sensille should print a vacuum adapter for the spindle
12:09 PM htasta: isn't overhead meant to be dont lift shit above people and not some height but rather where it is located and where people are?
12:11 PM roycroft: i think "overhead" is really meant to mean "vertical"
12:11 PM roycroft: i.e. hoisting vs. pulling
12:13 PM veegee: Yeah I think they just mean vertical lifting
12:14 PM veegee: But not sure why grade 70 shouldn't be used for that but grade 80 can
12:14 PM veegee: like 3/8" grade 70 has a higher WLL than 9/32 grade 80
12:14 PM veegee: are the failure modes different for grade 70? It's not an "alloy" steel, maybe that's why
12:15 PM enleth: veegee: probably to ensure that joe shmoe's "eh, it's thick enough, it's gonna hold" gut feel has a good safety margin
12:16 PM veegee: They're all rated for a 4:1 WLL
12:17 PM veegee: except grade 43
12:19 PM enleth: ah, right
12:20 PM enleth: it's probably about shock loads
12:20 PM htasta: HA! I was right lol. I just checked the NACM definition for overhead lifting: https://www.nacm.info/specifications/welded-chain-specifications/
12:20 PM htasta: Overhead Lifting
12:20 PM htasta: That process of lifting that would elevate a freely suspended load to such a position that dropping the load would present a possibility of bodily injury or property damage.
12:22 PM enleth: veegee: chain-supported loads like to drop a little when the chain untwists, untangles or skips over an edge
12:22 PM enleth: the forces involved are substantial
12:22 PM veegee: Yeah that makes sense
12:22 PM veegee: I still love chain over steel cable and web slings
12:22 PM enleth: alloy steel has a higher chance of surviving that
12:23 PM enleth: even if WLL is the same on paper
12:23 PM veegee: no matter what I do, the synthetic slings always look damaged. They have to be babied
12:24 PM veegee: yeah I'm sure the alloying elements increase toughness and all that for sure
12:27 PM veegee: enleth but for suspending things like lighting panels, blowers, and similar from the ceiling, grade 30 is officially ok?
12:27 PM veegee: Anytime I've seen it, they're definitely not grade 70, 80, or 100
12:28 PM veegee: And suspending a load from a ceiling is technically lifting, yeah?
12:28 PM roycroft: it definitely is
12:28 PM veegee: Albeit the load is like a feather compared to the WLL of of even 1/8" grade 30
12:33 PM roycroft: sometimes ratings like that are not based on actual strength, but on how they were tested
12:34 PM roycroft: if some standards board decided "we will only test grade 80 and above for lifting" then anything below grade 70 will not be certified for lifting, even though it may work perfectly well
12:37 PM enleth: veegee: static installation in construction might be covered by different regulations
12:38 PM veegee: roycroft ah yeah very true. They list the ASTM standard number or whatever
12:39 PM veegee: enleth and yeah I'll take a look at that, thanks. I'm going to be building some HEPA air filters and will be suspending the blowers from the ceiling
12:40 PM enleth: not sure what it's like in the US, here it's definitely not "lifting" when you suspend stuff and it just hangs there from a hook in the ceiling
12:40 PM enleth: there's no lifting mechanism in there
12:41 PM stinkpot is now known as gigas_cedar
12:45 PM roycroft: enleth: but when "lifting" and "overhead" are uses synonymously with "vertical load" that would make sense, no?
12:45 PM roycroft: if you suspend a load with a chain that is attached to a winch hook that would be suspending the load
12:46 PM roycroft: if you then activate the winch to hoist the load vertically, is the chain then "lifting" the load or is it still "suspending" the load?
12:46 PM veegee: especially at constant velocity, theoretical force is constant
12:47 PM veegee: so in ideal conditions, there would be zero difference
12:47 PM roycroft: and if it's not, then what is the force difference of suspending compared to lifting?
12:47 PM veegee: only during acceleration
12:47 PM roycroft: sure
12:48 PM roycroft: but if you "suspend" something with a chain, do you not generally attch the chain while it's slack, and then cause the load to accelerate downward so that the chain is tensioned?
12:49 PM roycroft: at which time you would be applying the same acceleration force as lifting would
12:52 PM enleth: roycroft: when you hang something from a hook in the ceiling, you do it once and it stays there as a static structure
12:52 PM veegee: https://www.youtube.com/watch?v=BbUGGhRq5HE
12:53 PM veegee: Well I was talking more about the laws of kinematics
12:53 PM enleth: if it hangs from a hoist, it's still "lifting" even if it's not moving at the moment - it could be moving the next moment
12:53 PM veegee: When you lift, the acceleration adds force on top of the force of gravity
12:53 PM veegee: Like every time you crank the lever on a chain hoist
12:53 PM enleth: those are still static forces anyway
12:53 PM enleth: not important here
12:54 PM enleth: the dangers of chain lifting are in sudden short drops
12:54 PM veegee: In my case, the weight of the object being suspended is < 100 lbs
12:55 PM veegee: so a piece of dental floss can hold it just fine
12:56 PM enleth: if it's entirely static, sure
01:17 PM JT-Shop: go from freezing my ass off to doors open and t shirt in 2 days...
01:18 PM * JT-Shop noticed that now is not the time to buy #1 SYP 2 x 12 x 20 $95
01:19 PM roycroft: that sounds almost like colorado, jt-shop
01:20 PM roycroft: now if you get a foot of snow faster than you can grab a coat i'll know you're secretly in colorado
01:27 PM JT-Shop: we usually don't get that much snow here but sometimes we have gotten quite a bit
01:31 PM roycroft: it's going to get up to 10 degrees here again today
01:31 PM roycroft: our weather is pretty boring these days
01:33 PM Tom_L: JT-Shop, gettin a tan today?
01:35 PM JT-Shop: open the door to the big shop so the sun could warm up the concrete and it's 72F in there now 40%
01:36 PM JT-Shop: looks like it will be some time before I collect enough 2x12's for my workbench...
01:45 PM roycroft: i need to get some 1x10s for the bookcase i'm getting ready to build
01:45 PM roycroft: i got some 2x12s for it around the end of november, and they are dry enough now to machine
02:07 PM internut: so who's in Colorado?
02:14 PM roycroft: a bunch of rednecks and hippies
02:14 PM roycroft: makes for a fun time
02:19 PM internut: Which are you?
02:21 PM miss0r: damn. Its only the end of the workday wensday, and I've already gathered 44 hours of work so far.
02:43 PM CaptHindsight: miss0r: that is because you take time out to sleep
02:46 PM CaptHindsight: Fry's went bankrupt
02:50 PM XXCoder: yep
02:54 PM roycroft: it's about time
02:55 PM roycroft: you can only get away with selling used, damaged goods as new for so long
02:55 PM roycroft: and since nobody in california goes to a physical store these days, and everyone has amazon prime, they probably all just buy the stuff they used to by at fry's off amazon now
02:56 PM * roycroft hasn't been to fry's in years, but the nearest one to him is in portland, close to 2 hours away
03:01 PM CaptHindsight: well they didn't sell much wood anyway
03:37 PM miss0r: CaptHindsight: sleep is overrated.
03:37 PM miss0r: well not sleep as a whole. Just the kind of sleep I am getting as of late. Its very segmented, being awakened 10 times a night because our smallest comes into our bed and starts kicking the shit out of me.
04:01 PM JT-Shop: hmm my buddy just gave me the hardware for a tail vise
04:17 PM -!- #linuxcnc mode set to +v by ChanServ
04:25 PM Tom_L: JT-Shop, how does that translate to mandarin?
04:27 PM JT-Shop: hmmm never tried to translate from tongue to mandarin
04:28 PM Tom_L: my dog has several names depending on how much trouble he gets into
04:30 PM JT-Shop: LOL
04:30 PM JT-Shop: my cat's nickname is Dickweed
04:34 PM XXCoder: tail vise?
04:34 PM XXCoder: oh interesting
04:36 PM JT-Shop: https://www.amazon.com/Taytools-775936-Workbench-Threads-Capacity/dp/B08MWRC1P5
04:36 PM JT-Shop: similar to that one
04:37 PM XXCoder: nice
04:37 PM Tom_L: single or double lead thread?
04:37 PM Tom_L: that's pretty coarse
04:38 PM JT-Shop: single 4 TPI
04:38 PM Tom_L: page said 3 but you also said similar...
04:39 PM Tom_L: http://tom-itx.no-ip.biz:81/~webpage/temp/thread1.jpg
04:39 PM Tom_L: that's 3 tpi
04:45 PM roycroft: i have one of those vise screws for sale
04:46 PM roycroft: along with a front vise screw
04:46 PM roycroft: i bought them about 20 years ago when i was going to build a scandanavian bench
04:46 PM roycroft: that screw should work out nicely for you
05:42 PM MrHindsight is now known as CaptHindsight
06:03 PM roycroft: i'm kind of bummed - the hour meters i ordered claim to ship from the us, but i've a feeling the seller imports them from china on a per-order basis, and then reships them
06:03 PM roycroft: and markes a shipped as soon as they leave china, not when they leave ohio
06:04 PM roycroft: i am ready right now to make the mounting piece for the power switch and hour meter on the bandsaw, and i can't finish that until i get the hour meter
06:05 PM JavaBean: in the 3dprinting world, whambam has been caught "drop shipping" from china... they ship from china using a us address on the from part of the sticker
06:05 PM roycroft: i probably can, as it's almost certain the dimensions will be the same as the ones i already have, but murphy told me that if i do that the ones i ordered will be a different size
06:05 PM roycroft: and murphy is always right
06:06 PM roycroft: if they are drop shipped from china with a us return address, that would actually be better
06:06 PM roycroft: because there would be no weather delay issue
06:06 PM roycroft: they would come to california an head north from there
06:06 PM roycroft: but they were due yesterday
06:21 PM JT-Cave: due doesn't seem to be a valid word right now
06:31 PM roycroft: this is true
07:40 PM chupacabra: my dern hardware keeps krapping out. Have one good pc it seems but i gotta get a paralell card for it.
07:41 PM chupacabra: Watching those videos on youtube and they are really explaining everything.
07:47 PM chupacabra: finally saw where to put the interface device name in.
07:47 PM chupacabra: then the machine died
07:51 PM Tom_L: at least you haven't found the password for the magic smoke yet