On Thursday 22 May 2014 03:25:24 Steve Blackmore did opine And Gene did reply: > On Wed, 21 May 2014 08:31:19 -0400, you wrote: > >Since lcnc has no clue about the ballistics of the reverse, and > >therefore cannot predict the over travel, I'm not sure there can be a > >fix for that other than setting the -limit well into the chuck. > > My neg working units limit is often well into the spindle - cant > bore/drill etc inside the chuck otherwise. I have a moveable limit > switch on the spindle end of the bed and a home/limit switch on the > base of the tailstock where the saddle hits it.
My tailstock isn't even mounted unless I am center drilling something. But that would be a neat trick I should remember. :) But the home switch is under the rear edge of the bed, rigged so the back gib depresses it. Not portable, but also out of swarf's way so far. > However - I don't use home in LinuxCNC, it's not lathe friendly - I don't find it all that helpful for other than reestablishing positions after a forced shut down in the middle of a job, chip broke, whatever. > I have no homing set in ini. Limit switches are enabled though. I simply > zero on the end of the work. Just have to remember to leave enough > stuck out the chuck so the tool don't hit it on external > turning/threading and parting off. I have done that too, with a touch off, or occasionally, when the piece has been cut off, clean up the nipple on the end and slide the workpiece up to the zeroed tool for the next piece. Cutting off is a PIMA on this piece of rubber, and I finally wrote a routine that will work for one cutoff per cutoff blade sharpening. It goes inward about .2mm then pulls back before it can dig in and lock things up, then moves .5mm sideways and repeats back and forth, preventing the blade from being pinched in the groove, till it finally parts off. Then I have to remove about 3mm of the end to get back to a full width tool. > The end of the stock is my master datum point Z0. Everything else > relies on that. CAM sorts out the tool change position for each tool > and the start/finish "at rest" position. My tool table in CAM is set > up. It's all zero's in LinuxCNC. > > CAM knows the shape, working length and overhang for each tool. (plus > lots of other params) and works out tool paths using all these > parameters. Frightens me at times when the tool misses the end of the > job by tiny amounts - I have it set to adjust them as work > diameter/length changes during the job if I am making a lot of parts - > saves time. No CAM here other than pcb2gcode for circuit boards which are done on the mill. So I'm stuck writing my own gcode. Obviously single operation loops, rarely more than 40 LOC. CAM's aren't great at that anyway. > Steve Blackmore > -- > > ----------------------------------------------------------------------- > ------- "Accelerate Dev Cycles with Automated Cross-Browser Testing - > For FREE Instantly run your Selenium tests across 300+ browser/OS > combos. Get unparalleled scalability from the best Selenium testing > platform available Simple to use. Nothing to install. Get started now > for free." > http://p.sf.net/sfu/SauceLabs > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> US V Castleman, SCOTUS, Mar 2014 is grounds for Impeaching SCOTUS ------------------------------------------------------------------------------ "Accelerate Dev Cycles with Automated Cross-Browser Testing - For FREE Instantly run your Selenium tests across 300+ browser/OS combos. Get unparalleled scalability from the best Selenium testing platform available Simple to use. Nothing to install. Get started now for free." http://p.sf.net/sfu/SauceLabs _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
