#linuxcnc | Logs for 2013-07-27

[00:01:03] <RyanS> Why on earth is a core drill as used on magnetic drills called a broach cutter ie like the linear cutter that does keyways? Not even a similar process
[02:20:35] <DJ9DJ> moin
[06:13:37] <pimperle> hi. I just compiled and installed my first kinematics module. when using manual control the gui now reflects the path my mirror-controlled laser takes on the table. however it only moves one joint at a time, not one axis at a time (thus moving both joins to get a straight line).
[06:13:56] <pimperle> Is manual control supposed to operate on joints (and not axes)?
[07:12:09] <pimperle> also: if i manually move my axis to zero and then hit "Home All", the X axis jumps to approximately 3 immediately. Why does't it do that? isn't home == (0,0)?
[07:13:13] <jthornton> you might have an offset in effect
[07:13:24] <jthornton> just the DRO moves?
[07:41:17] <DJ9DJ> re
[12:12:57] <IchGuckLive> hi all
[12:13:28] <IchGuckLive> murder day as we hit 110F today here and the plasmas got very hot on work day
[12:14:47] <mozmck> 110F? in Deutchland?
[12:15:06] <IchGuckLive> yes its the africa heat
[12:15:35] <mozmck> didn't know it got that hot there! Does here in Texas often.
[12:15:52] <mozmck> but it's cool and has been raining lately.
[12:35:37] <IchGuckLive> im off have a nice wekend where ever you are !
[14:14:48] <jthornton> wow it's going to get down to 56f tonight
[14:15:16] <archivist> we have a thunderstorm atm
[14:23:53] <pimperle> jthornton: there is no offset configured in the ini file and HOME_SEARCH_VEL is also zero (which otherwise would seem to explain the behaviour).
[14:24:11] <pimperle> unfortunately i don't know what DRO moves are
[14:25:16] <jthornton> the DRO is the Digital Read Out of your position
[14:29:45] <pimperle> ah, ok. no, the x axis physically makes a little step as well
[14:30:37] <pimperle> as soon as i hit "home all" it makes a small jump and then comes to rest right on a mark which seems to resemble a cross hair on the linuxcnc preview pane
[14:30:53] <pimperle> (i'm sorry that i don't know all the right terms yet)
[14:50:20] <JT-Shop> pimperle: is this a stepper?
[14:51:23] <spack> i found a decent old tree mill for a decent price. supposedly running... but i have nowhere to put it :(
[14:51:36] <JT-Shop> put it in my shop
[14:51:42] <spack> where's that?
[14:51:58] <JT-Shop> Swamp East Missouri
[14:52:12] <spack> little bit too far...
[14:52:49] <spack> :(
[14:53:15] <JT-Shop> I figured that I'm a geographical oddity and live 2 weeks from anywhere
[14:57:07] <spack> heh
[14:58:08] <archivist> but he does not mind fetching on his trailer :)
[14:58:33] <JT-Shop> I'll only go half way across the country to fetch things :)
[14:58:53] <spack> i'm not that far
[14:58:58] <spack> chicago
[14:59:05] <spack> but too far for this purpose
[14:59:06] <spack> :)
[15:00:05] <archivist> hey I went to Baltimore from near Chicago to fetch a signal generator
[15:00:34] <archivist> and back to Ohare for the flight home
[15:02:55] <archivist> rental car went back with more miles on the clock than they expected probably :)
[15:03:46] * JT-Shop has the cleaning tank ready for action... 1 down 4 to go
[15:05:11] <CaptHindsight> spack: that one in the NW burbs?
[15:10:13] <Tom_itx> JT-Shop, you only have to go half way either way :)
[15:12:54] <sbbrtn> does anyone know where the main loop is in linuxcnc?
[15:14:44] <CaptHindsight> http://chicago.craigslist.org/nwc/tls/3959995112.html "The original owner died shortly after purchasing it."
[15:15:18] <JT-Shop> Tom_itx: yep unless I go to my birth place and that is a lot longer than 1/2 way
[15:18:03] <JT-Shop-2> sbbrtn: it's a script
[15:20:39] <syyl_> that looks like a sturdy machine, CaptHindsight
[15:20:46] <syyl_> ...
[15:21:03] <syyl_> sturdy for drilling cheese or so...
[15:21:56] <CaptHindsight> heh, is that like buying a house where "owner died shortly after purchase"?
[15:22:18] <syyl_> i think its a sign not to buy that machine
[15:22:19] <CaptHindsight> why would they put that in the ad?
[15:22:19] <syyl_> :)
[15:22:40] <syyl_> maybe they want to show the reason, why they sell it?
[15:22:51] <syyl_> (or the reasen the owner died...)
[15:39:41] <spack> CaptHindsight: yeah, libertyville i think?
[15:39:59] <spack> is that nw? i don't know where shit is around chicago
[15:44:11] <CaptHindsight> yes, 45 min north of the city
[15:45:11] <Tom_itx> JT-Shop you got a point there.
[15:45:20] <CaptHindsight> spack: you want me to look at it for you?
[15:45:22] <Tom_itx> JT-Shop, you tried a batch of anodizing yet?
[15:46:18] <spack> CaptHindsight: i might head up there tomorrow if he didn't sell it to a guy this morning
[15:46:26] <spack> i'm waiting to hear back from him on if the dude bought it or not
[15:46:57] <JT-Shop> Tom_itx: working on getting everything set up
[15:47:18] <JT-Shop> I hacked a 300 watt fish tank heater to go to 140f
[15:47:27] <Tom_itx> i expect a full write up :)
[15:47:34] <JT-Shop> broke one figuring it out but they were free
[15:47:46] <Tom_itx> you need a temp control on it now
[15:47:54] <Tom_itx> pid
[15:48:10] <JT-Shop> no the factory temp control works fine, I had to hack it to go above 90f
[15:48:12] <CaptHindsight> 140F heater for low temp sealing?
[15:48:22] <JT-Shop> cleaning and dye baths
[15:48:26] <Tom_itx> oh
[15:48:29] <JT-Shop> 210 for sealing
[15:48:57] <spack> CaptHindsight: are you also NW?
[15:49:13] <CaptHindsight> yes
[16:00:19] <pimperle> JT-Shop: it's a 5v dc motor with an magnetic encoder attached to it (built it myself)
[16:00:46] <pimperle> the encoder feeds into a hal encoder and provides position feedback for a pid loop
[16:05:07] <JT-Shop> sounds like a hardware problem to me
[16:23:24] <pimperle> JT: thanks for the hint. It actually jumps to this kind of crosshair mark. I'll investigate the hardware.
[16:23:26] <DJ9DJ> gn8
[19:55:22] <andypugh> jthornton_: Is the plan to breed the fish then cook the fish, all in the same tank?
[20:01:36] <CaptHindsight> http://www.3ders.org/articles/20130725-nasa-hot-fire-tests-show-3-d-printed-rocket-parts-rival-traditionally-manufactured-parts.html
[20:03:57] <Tom_L> CaptHindsight i posted that the other day
[20:04:11] <Tom_L> maybe not in here...
[20:10:07] <CaptHindsight> I always seem to end up with machines that somebody didn't know how to wire properly
[20:12:10] <CaptHindsight> they ran the analog 10V for the spindle amp along the AC mains and also ran the 10V reference source ~8 feet through just about everything
[20:12:34] <CaptHindsight> and then thought that the servo board was bad :)
[20:13:05] <WalterN> heh
[20:13:31] <WalterN> CaptHindsight: I just learned about microstepping for stepper motors...
[20:14:32] <CaptHindsight> step by step
[20:15:08] <CaptHindsight> bbl
[20:16:12] <WalterN> also, it seems hard to find US standard pitch ballscrews
[20:16:25] <AR__> doesnt matter
[20:16:41] <AR__> you can just estimate and then measure travel for calibration
[20:17:30] <andypugh> 1 inch is _defined_ as 25.4mm The computer can do the maths. LinixCNC is metric internally anyway.
[20:19:24] <WalterN> also, I'm not sure where a good place is to buy something like an SKF ball screw
[20:21:15] <andypugh> You probably don't need a high quality ballscrew. Cheap Chinese ones are likely to be quite good enough.
[20:21:54] <WalterN> I still want to look at the quality stuff first, then I'll probably decide that its too expensive and look at cheaper stuff
[20:22:16] <WalterN> but I still need to start with the good stuff XD
[20:23:00] <andypugh> it is very unlikely that you make parts where you care that 2'0.0001" is not the same as 2'0.0002"
[20:23:46] <andypugh> And even the worlds worst ballscrew can move accurately over short distances.
[20:24:26] <WalterN> the point is that all options must be explored
[20:25:29] <AR__> i scored some good used ones on ebay
[20:25:43] <AR__> just gotta dig around and get lucky
[20:27:31] <WalterN> so... where do you go to buy that stuff (new)?
[20:29:13] <andypugh> I generally go to Zapp: http://www.zappautomation.co.uk/en/60-c7-ballscrews
[20:30:31] <WalterN> UK?
[20:30:34] <WalterN> meh
[20:43:40] <WalterN> whats the difference between a rolled ball screw and a ground ball screw?
[20:53:17] <WalterN> http://www.automation4less.com/ maybe?
[20:54:04] <Tom_L> cost and precision
[20:54:15] <jesseg> and manufacturer process
[20:58:38] <WalterN> I guess I always assumed that ball screws were ground
[20:58:42] <andypugh> Rolled is cheaper than ground. Nowadays, though, a good rolled screw is better than a bad ground one.
[21:00:53] <Tom_L> yeah but how do you tell the difference when ordering?
[21:03:50] <andypugh> They tend to be graded. But: If you have a way to notice that your ballscrew is inaccurate, then you have a way to correct it.
[21:05:45] <andypugh> I susoect that (unless you are very much into metrology) even a cheap ballscrew will be the most accurate measuring device you own over the length of your machine bed,
[21:06:29] <WalterN> yeah
[21:06:38] <WalterN> that and the linear bearings
[21:07:35] <Tom_itx> speaking of ballscrews: http://www.thingiverse.com/thing:112718
[21:07:43] <Tom_itx> not for mill but interesting
[21:10:28] <andypugh> It's a really good system if you have secondary position feedback
[21:10:47] <jesseg> How is it heat resistant and heat printed? Does it just print hot?
[21:10:56] <jesseg> wrong window :D
[21:12:13] <Tom_L> that and some linear encoders might work
[21:13:32] <andypugh> There is a similar device with grooved (not threaded) rollers running in a threaded rod. Simlarly zero backlash, low rotation torque, no danger of slipping.
[21:13:58] <Tom_L> high helix?
[21:14:02] <Tom_L> probably
[21:14:59] <andypugh> Not necessarily. Imagine that thing, but put a thread on the rod and grooves on the (tilted) bearings to match.
[21:15:02] <Tom_L> or maybe pointed OD on the bearing?
[21:15:12] <Tom_L> yeah
[21:16:23] <Tom_L> just a 60 deg outer race would work on a standard thread wouldn't it?
[21:19:06] <Tom_L> and you could grind/cut the thread to whatever pitch you like
[21:21:53] <andypugh> It will work for _some_ standard threads.
[21:22:40] <andypugh> Just being pedantic, Whitworth is 55 degrees, BA is 47.5 degrees, PG is 80 degrees (yes, really)
[21:22:52] <Tom_L> yeah yeay
[21:22:54] <Tom_L> h*
[21:23:32] <Tom_L> as long as the V on the bearing matched the thread
[21:34:58] <andypugh> I have not yet found out _why_ Whitworth is 55 degrees. There has to be a reason?
[21:37:00] <WalterN> fff
[21:37:49] <WalterN> having a hard time finding a place that sells a nice selection of ballscrews that does not expect me to call in for a price
[21:40:17] <andypugh> They may want to quote for end machining. Do you have the means to machine the ends?
[21:40:47] <WalterN> guess I could if its not really hard material
[21:41:19] <WalterN> do they normally surface harden it?
[21:41:55] <andypugh> Oh yes.
[21:42:21] <andypugh> About as hard as ball bearing races.
[21:42:21] <WalterN> surface? or harden the whole thing?
[21:42:27] <andypugh> Surface
[21:42:36] <WalterN> thats not so bad
[21:42:42] <NickParker> where's a good place to go looking for reading on my bandit controller?
[21:42:52] <NickParker> I suppose it's much to old to have a manual floating around as a .pdf huh?
[21:43:26] <andypugh> I use CBN tooling to machine ball screws. Carbide is a bit marginal (you can, of course, soften the ends)
[21:44:13] <WalterN> well
[21:44:16] <WalterN> there is this... http://www.automation4less.com/store/proddetail.asp?prod=RM1605-0550-0400-FS
[21:44:44] <WalterN> but its a little bigger in diameter than I want... I'd prefer something like 13-14mm in diameter
[21:45:01] <NickParker> aliexpress has TONS of ball screws
[21:45:09] <NickParker> if you don't mind shipping time and a gamble on quality
[21:46:40] <NickParker> http://www.aliexpress.com/wholesale?SearchText=ball+screw&catId=0&initiative_id=SB_20130727183137
[21:47:11] <andypugh> WalterN: I recently bought a special-order preloaded 16mm ballscrew from Gten, via Zapp, for £99.
[21:47:34] <WalterN> andypugh: thats UK/europe though
[21:47:48] <andypugh> It came from China
[21:48:48] <andypugh> Have you tried eBay?
[21:49:02] <WalterN> I'm specifically avoiding ebay
[21:49:13] <NickParker> aliexpress is probably out of the question then..
[21:50:24] <andypugh> Because you want to spend more money than necessary?
[21:50:26] <andypugh> http://www.ebay.com/itm/SFU1605-Ball-Screw-L300mm-with-Ball-Nut-Both-end-Machined-/121105055219?pt=LH_DefaultDomain_0&hash=item1c326c7df3
[21:51:29] <andypugh> Or, a preloaded one here, machined $15 (so far) http://www.ebay.com/itm/1-anti-backlash-ballscrew-1605-190mm-C7-end-machined/300937679896
[21:52:41] <Tom_L> how much useable travel would that be?
[21:52:48] <Tom_L> ~5" ?
[21:52:56] <Tom_L> or less
[21:52:58] <NickParker> depends how you do it.
[21:53:11] <andypugh> I am afraid that I can't advise on how to find extra-expensive extra-quality screws, I just buy the cheapest and so far have no complaints.
[21:53:56] <WalterN> rolled is fine... its just finding a good source
[21:54:59] <WalterN> I found a couple places that sell NSK...
[21:55:30] <WalterN> its about $750 for an NSK ballscrew
[21:56:37] <Tom_L> that first one is $85 with the pillow blocks and coupler
[21:56:53] <NickParker> what are you planning that requires $750 ballscrews?
[21:57:00] <Tom_L> err no, it's 400mm
[21:57:14] <Tom_L> http://www.ebay.com/itm/1pcs-antibacklash-ball-screw-1605-L400mm-C7-BK-BF12-2pcs-6-35-10mm-couplers/290825164349?rt=nc&_trksid=p2047675.m1851&_trkparms=aid%3D222002%26algo%3DSIC.FIT%26ao%3D1%26asc%3D16803%26meid%3D158228476220722034%26pid%3D100005%26prg%3D7926%26rk%3D1%26rkt%3D4%26sd%3D121105055219%26
[21:57:32] <elmo40> 10"
[21:57:38] <andypugh> I just made a dummy order. Zapp will deliver to the US for £15.
[21:57:46] <elmo40> err, 15" long
[21:57:49] <elmo40> that is stubby
[21:58:08] <elmo40> why such a short ballscrew?
[21:58:17] <WalterN> yeah
[21:58:20] <Tom_L> it would fit my sherline
[21:58:24] <WalterN> I'm just making a rapid prototyping machine
[21:58:24] <Tom_L> maybe
[21:58:44] <WalterN> for the Z-movement, X and Y are done with the galvos
[21:58:55] <WalterN> so I only need one
[21:59:43] <andypugh> You don't need a ballscrew for an RP Z axis. The force is always in one direction, a conventional screw really is just as good.
[22:01:48] <andypugh> The stages on the £40,000 bond-testers I used to design used acme threads and a spring. There was simply nothing to be gained from ballscrews (and the backlash is _lower_ with the screw and spring arrangement when you have no cutting force)
[22:03:16] <WalterN> oh, I didnt think about the spring thing...
[22:03:26] <WalterN> still, a ballscrew would be nice
[22:04:18] <Tom_itx> for no force, http://www.thingiverse.com/thing:112718 would also work
[22:09:22] <WalterN> hmm
[22:10:31] <WalterN> I think I'm going to stick with a cheaper ballscrew
[22:12:05] <NickParker> if you're going cheap just go for aliexpress
[22:12:13] <NickParker> $40 300mm
[22:12:20] <NickParker> probably $40 600mm on there
[22:23:27] <kwallace> NickParker: http://www.wallacecompany.com/machine_shop/Shizuoka/atc_manual/
[22:23:44] <kwallace> http://www.wallacecompany.com/machine_shop/Shizuoka/Instructions/
[22:24:16] <kwallace> http://www.wallacecompany.com/machine_shop/Shizuoka/DC_Spindle/ but probably doesn't apply.
[22:24:51] <jesseg> hahaha!
[22:25:31] <NickParker> sweet thanks wallace
[22:25:51] <NickParker> also after i'm done going through this i might have to ask you to check voltage across a particular cap
[22:25:57] <NickParker> but i'll see where i can get with all thi
[22:25:58] <NickParker> s
[22:26:16] <jesseg> How do I disable the LinuxCNC distro from locking the screen during a print job? LOL. I don't want to have to type my password if I want to quickly stop LinuxCNC ha ha ha
[22:30:03] <skunkworks> it is an ubuntu thing.. go into screensaver iirc
[22:30:42] <skunkworks> it is an ubuntu thing.. go into screensaver iirc
[22:30:47] <skunkworks> heh
[22:30:59] <skunkworks> jesseg: you should have an external estop
[22:31:04] <skunkworks> hardwired
[22:31:15] <jesseg> hehehe I just imaged that being a controller for a machine, someone would make it ship with auto screen lock disabled.
[22:31:43] <jesseg> skunkworks, of course.. but still.. ha ha ha.
[22:31:50] <skunkworks> can't think of everything...
[22:31:54] <skunkworks> :)
[22:32:07] <jesseg> Maybe I'll send them a note and they'll consider it for their next release.
[22:32:58] <jesseg> oh
[22:33:00] <jesseg> wait.
[22:33:02] <jesseg> this is them!!
[22:33:10] <spack> pretty sure mine was off by default
[22:33:15] <spack> it doesn't even black the screen
[22:33:52] <kwallace> There are a few options available for the screen saver, no password or no saver are a couple.
[22:34:48] <NickParker> hmm kwallace did you replace the power supply(s) in your mill?
[22:35:14] <NickParker> The 4th heatsinked board and the huge transformer/capacitors?
[22:39:28] <kwallace> I recall reusing most of the supply stuff. Not the fourth heatsinked board.
[22:44:21] <kwallace> The large transformer has several taps. The motor supply uses the 45V taps, a diode bridge and large caps and is unregulated. Now that I'm thinking about it, that may be the main use for that large transformer.
[22:46:49] <kwallace> My PC supplies 5V and 12V. There is a smaller transformer that I reused that converts 240 to 110 for a relay. I think I use another tap off the large transformer for 24V.
[22:52:43] <kwallace> http://www.wallacecompany.com/machine_shop/Shizuoka/00004-1a.jpg This shows the 240 to 110 xfrmr and relay which switches the 240 mains. This board now has a PC on it and is filled up. I'm trying to decide on how to make a steel box, but the mill works fine as-is.