Perhaps I misunderstand but why do you plan to cut the thread in short pieces rather than the whole length but obviously in several passes due to allowed DoC and WoC? Is the final thread diameter to be about 2-inch or much smaller? In any case shouldn't you make the stock approximately round prior to cutting any threads?
-----Original Message----- From: gene heskett <ghesk...@shentel.net> Sent: February 25, 2022 10:16 AM To: Enhanced Machine Controller (EMC) <emc-users@lists.sourceforge.net> Subject: [Emc-users] Couple Q's re 4th axis on a mill. Greetings all; I am about to install this rebuilt rotary drive on my 6040 mill, aligned to rotate stuff on the Y axis, which is the long axis on a 6040. Out of the alphabet of ABCUVW, which is the proper axis to call it? It will for the next job, be turning a 2"x2"x18" on center of its 2x2 end, stick of hard maple, carving a 2 start buttress thread that 18" long to make a screw for a leg vise paddle on my woodworking bench. And, does this change the kinematics module which is trivkins now? The intention is to turn the stick while advancing Y at 2x the pitch per rev of this axis, rotate the stick 180 degrees and reverse it to come back, carving the the 2nd start thread on the back stroke. Then advance both Z in the profile of the thread, doing a forward stroke up this 2nd start, back up the new axis by the 180 it was advanced to come back on the 1st start path. Then advance the starting rotation position along with a z to the next point in the profile, wash, rinse and repeat until the full depth of the buttress thread has been carved. Done right, both thread starts will get cuts from both directions of Y travel. Automatic backlash comp, although this mill does not seem to have measureable backlash. I used it to carve its own ER chuck wrenches from 1/2" alu plate, and should have added another thou, they fit very tightly. I am assuming that I can drive this new axis from 30,000 degrees to 30,180 and back to 30,000 at the back end turn around wihout the axis doing any mod[360]'s on me. And while I've yet to start the g-code itself, I'm thinking I should fix the y linear start and stop points, but increment the rotational degrees to carve the threads profile by small advances in Z vs rotation start. The dead center end of the stick could then have threads clear to the end without an entry groove, it would just run off the end of the stick. At the speed this rotary can move with its printed 50/1 harmonic drive, this could easily be a 3 or more day job. With lots of vacuum cleanup. I've obtained 20 SC, 1/16" ball nose cutters, some with 3/16" LOC, some with 1//4" LOC. With that puny a cutter, I do expect to dull and break some of them. Comments/guidance to keep me from doing something stupid would be much appreciated. Thanks all. Take care and stay well. 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, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
