On Thu, 10 Sep 2009 08:12:05 -0500, you wrote: >> "F" controls the speed of travel in the direction of tool movement, >> whereas "K" sets the speed explicitly in the Z direction. > >In EMC2, K specifies the motion distance per rev in any direction. So >if you're turning a tapered thread you just specify the feed per rev >along the hypotenuse. If it is a 5 degree taper and you want 10 >threads per inch, K would be 10/cos 5.
>> "F" could have been used for the lead in G33, but it would have been >> inconsistent with its meaning elsewhere (though this is not >> immediately obvious for conventional parallel threading operations) It's totally unconventional now as you've explained the Op (CAM) has to do mathematical juggling to get the pitch correct on a taper thread. I see that's open to mistakes too <G> The pitch of a taper thread is measured along its axis just the same as a parallel thread, not along it's taper. See http://www.misumiusa.com%2FCategoryImages%2FMetric_2009_pdf%2Fp2843.pdf and is the same for all commercial threads as I'm aware of. Some examples, a 1/2" x 14 NPT pipe thread Fanuc 11 style T0101 X-0.9558Z0.3005M8 G04U2. X-0.7441Z0.2461 G33X-0.8136Z-0.8657F0.0714 G0X-1.0285 Hass SL N130 ( TOOL: T2 = OD_UN_SW ) N135 T202 N140 X0.9558 Z0.3005 M03 N145 G76 X0.7488 Z-0.8823 I-0.0364 K0.0571 D0.0057 F0.0714 Siemens 810 (Bizarre controller) N145 D2 ( TOOL 2 OD_UN_SW ) N150 G95 S2940 M3 N155 M8 (MSG, THREAD: OUTER THREAD1 ) N160 G0 Z1.0 N165 X2.0 N170 Z0.3005 N175 X0.9558 N180 R20=0.0714 R21=0.7758 R22=0.2461 R23=0 R24=0.0571 R25=.001 N185 R26=.1 R27=.05 R28=10 R29=27.21 R31=0.8453 R32=-0.8657 In all cases the Z feed was 0.0714 per rev which is 1/14th of an inch, as was another dozen different controllers I looked at. >We considered "F" but chose "K" because we didn't want G33 to mess >up the feed of non-threading moves. I can see it either way and I >think the distinction makes no practical difference. Got to ask why doesn't it mess up for nearly every other controller out there? >> Incidentally, EMC appears not to be unique in this usage: >> http://pdf.directindustry.com/pdf/delectron/g-code-programming-manual/14577-33189-_23.html An obscure Italian Mill >Interesting - this one looks like it matches our usage exactly. > >> http://www.omni-turn.com/Media/Manual/G33%20threading.PDF Linux based control perchance ;) Steve Blackmore -- ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
