On Monday, February 21, 2022 1:26:58 PM EST andy pugh wrote: > On Mon, 21 Feb 2022 at 17:33, gene heskett <ghesk...@shentel.net> wrote: > > G76 isn't terrible handy for a buttress thread being carved on a hard > > maple stick 20" long for a woodworking vise, turned by a B axis, with > > the 24k rev spindle doing the carving while y is being advanced by > > the pitch per rev. > > OK, in that case I would code > > G96 G1 Y-20 B28800 F0.001 > > (Well, actually, I would calculate the F rather than guess it) In that case, since B will be scaled such that B scale is one exact turn then I would go y at a speed that follows the pitch such that 1 turn advances at 2x the pitch, with a second pass thats offset whatever half a turn of B is in y motion.
how about I lift z clear at the rear of the Y, run B half a turn, restore Z and come back with Y, and B that same half a turn, so it tracks thread 1 going to the rear, and thread 2 coming back. At the end of the pass back to y0, add 1.5 thou fwd for Y, and 1 thou for Z. Wash, rinse and repeat till z has arrived at the bottom of the thread, then make another 20 passes incrementing both ends of y to cut a sorta flat at the bottom of the thread. > You could use CAM, but I don't know of any free-to-use CAM systems > that do proper rotary axis work. Who needs CAM if he understands what is needed, AND linuxcnc can keep B and y in sync. Both completing a many turns of B move at the same millisecond. Doesn't seem like rocket science other than the end of stroke math to advance both Y and B by synchronized amounts for the next cut. The std trivial kinematics should be able to do that. Or am I missing something? Thanks Andy. 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
