On Friday 01 June 2018 16:44:25 andy pugh wrote: > On 1 June 2018 at 21:06, Gene Heskett <ghesk...@shentel.net> wrote: > > The only way I can see to fix it, requires a calibration per tap, > > I think I would have already tapped them all by hand. > > But then I nearly always do, I don't think I have rigid-tapped more > than half a dozen times.
While I expect I have tapped 2x the holes by rigid tapping that I have done in the last 5 years, than I have tapped by hand in the previous 70. The work flow is to drill the hole for the taps shank, which may involve checking half the drill bits on hand to find one that is between the exact shank diameter and perhap .010mm smaller, and sharpen it if its needed. Put in the chuck mounted on the mills bed toward the right end of the bed. Put a slug upside down in the 7/8" R8, take the table to 187.003mmsX and around .340mm'sY. Bring the head down at 40mm's till it throws the first flake of brass, set the jog slider down to .2mm/minute and let it gnaw a pretty well centered dimple in the brass. Run the jog up to 60mm's or so and run it down until I hear it go by the end of the keying bolt in the other end of the slug. Run it up the post 200mm's and test the taps fit in the resultant bore. If so tight it won't go, get the next bigger bit and ream it out a bit. This part may take 5 minutes. Remove the slug from the spindle and put in the R8 chucked in the table as the A axis. Remove the 7/8" R8 and put a 3/4 back in the spindle, and put the tap drill in it. Edit the 2 or 3 vars at the top of the file to make it drill the 4 holes. Move the table to the right a bit or remove the drill from the table mounted chuck to keep the two drills from hitting each other, and hit r. Grab a 17mm wrench and hold down on the slug to keep it from grabbing the slug as it holes thru into the shank bore each time. In the meantime its making odd motions as it restores the machine to a power up and homed state, then it runs over to the contact pad and does a g38.1 at 160mm/minute to find out how long this drill is. Applies a G92 Z[offset], runs it back above the work and returns from the subroutine call, then moves to the holes location, runs A to -10 and back to zero, drops the bit to a sheet of paper above the work having started the spindle at 1k revs a move or so back. Goes down at 2mm's for 1.5mm, which allows the bit to get itself centered, then ups the feed to 40mm and completes the hole, with me holding the slug with an endwrench straddling the bit. Back it up far enough to clear and drive the A table to 90 degrees. Wash, rinse and repeat till the table has been to 270 degrees. Run head up out of the way. This is perhaps 3 minutes. Change the drill for the tap, blow all the brass off the contact and tap, and tell the gcode its tapping this time. Give it a squirt of tapmagic or buttercutt. hit r. The sub re-finds everything, and once the tap has been measured, runs it over to the hole, taps the hole, backs up enough to clear, runs the table to 90 degrees, tap that hole, wash rinse and repeat 2 more times, run it way up the post and reset the A to zero degrees. Another 4 minutes. Install grub screws and tap, 3 minutesmax unless the tap is too tight a fit and has to be hammered in, take it out to a table in front of the garage and stamp the bottom face of the slug with this taps size and tpmm. So once I've put the slug in the spindle, its perhaps 20 minutes by the time its stamped and dropped in the storage box. And my wrists aren't tired from cranking on a tap handle. Nor did I break a tap. BTDT, way too many times in my 83 years. -- 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> ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
