On Thursday 20 June 2013 11:20:45 Jon Elson did opine: > Gene Heskett wrote: > > 2. Set up a choice of homing sequences, one for a normal, cuts on the > > far face turning tool, and one that inverts the X homing sequence for > > calibrating a boring bar. And establishes the two different sets of > > HOME_OFFSET because a different set of contact faces on the gauge are > > used. > > Why would you need a different homing sequence for different tools? > I can't see why you need this. Is this because you have tools on > the back side of the part, and you want CSS to work? Or, is it just > to make the X coordinates run the right way? > Interesting problem. I'll bet there's a better way to do this. > > Jon
The cutting tooth is what is being used for the electrical contact, with some trickery in the .hal file to derail the "probe contact while jogging logic" and steer the probe signal pin to the homing logic ONLY while homing. Seems super sensible to me since its the tooth that is actually doing the cutting., so why not measure it? :) That of course doesn't work for Z when the threading tool is mounted, but the side of the toolholder seems to work just as well. The same comment of course applies to the end of the boring bar as the actual tooth is, for a conventionally shaped bar, not on the end of it, but I often use an .125 milling bit, set in a drill chuck mounted in a boring bar holder, with the toolpost turned 5 degrees CCW as a boring bar for small holes, like the pocket for a #209 primer, supposedly .240" diameter but very sloppily made, I've measured some that were .007" out of round right out of the box! Apparently shotgun hulls don't care. :( The cutting tooth of the boring bar is of course on the near side of the tool, whereas the normal turning tools cutting edge is on the far end. My gauge has contact surfaces arranged to sense both front and rear points. That of course needs a reversal of search directions for the X only. The gauges contact for front edged tools is a swing down & lock in place arm, with only smallish 3/8" square contacts, but the Z is offset about 1/4" to the right, which needs a Z axis HOME_OFFSET set to compensate. The rest of the file sets Z left limits about 10 thou off the face of the chuck jaws, and X limits about 50 thou short of the end of mechanical travel in and out. Except for those details, the .ini files are (or should be) identical, and it would be a huge advantage to actually use the same file but setup 2 buttons HOMEN(ormal) and HOMEB(bore) which would when clicked, call the correct homing sequence file for the tool mounted. That would also have the huge advantage of not needing to stop and restart LCNC just to fine tune an axis's 0.0000 position. X of course is the problem child here, and I should plow a pocket in the left end of the gauge to make room for the test turning piece so I don't have to remove it to re-home it to the gauge. There is sufficient stock that I can plow a groove for an inch of stickout of some 1/2" stock for test cuts so I don't have to remove, then remount and recenter the test piece. Perhaps that can be todays gauge improvement, but I intend to get to the range and test a new bullet seating tip for the ramrod today too. This particular bullet, a swaged 300gr HPBT that looks like the ultimate deer slayer, but a poorly fitted seater on the ramrod can do serious damage to the hollow point geometry, which will turn one hole groups into a a cylinder bored shotgun pattern. The bullet maker supplies a plastic rod tip but its stem is easily broken off in the ramrod face and I have one that needs some time on the cook stove to burn the remains out to where I can finish cleaning it out with the properly sized tap, an 8-32 IIRC. I need to find my round tuit at the same time the missus is gone for long enough that the stink will dissipate, which likely would not be doing her COPD any good at all. :( So that is the reasoning behind this need for a separate files containing the homing instructions. And it seems to me that this could, rather than scratching just my itch, be a worthwhile general improvement in how we treat and calibrate a lathe, usable by everyone running a lathe with LinuxCNC once they 'get the hang of it', because there would be lots less time wasted making test cuts on scrap material. I just found two spare pins in the parport, the hal config assigns an A axis I don't have, so pins 8 nd 9 are available, so I can now go ahead and make the braking R switching control out of a wcomp module looking at encoder-velocity. That could speed up the G33.1 stuff by short circuiting 2/3rds of the 3 or 4 turns of overshoot I'm getting now as it virtually coasts to a stop with a 16 ohm 40 watt load R. Below 400r's or so, 4 ohms at 40 watts should be safe for the PM magnets I'd think. Thanks Jon, I'll get me coat now :) Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> is up! My views <http://www.armchairpatriot.com/What%20Has%20America%20Become.shtml> Let others praise ancient times; I am glad I was born in these. -- Ovid (43 B.C. - A.D. 18) A pen in the hand of this president is far more dangerous than 200 million guns in the hands of law-abiding citizens. ------------------------------------------------------------------------------ This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
