My personal choice has been a CAT40 with rigid Bilz #1 holder, or a U200 shank with very minimal tension compression and Bilz #1 holder
Bilz holders appear a bit pricey but you won't need many sizes and you can swap taps and holders while keeping the same offset - I'd say mine repeat to about 0.0025" I have put the shank in a CNC and just swapped tap holders on jobs which had too many different threads. I also have some 3/4" shank tension/compression #1 holders - but they are like 4 inches long. I can't use these on a BP style 3 axis CNC with only 5" Z quill travel. I hope to some day add a "W" axis so I can use the knee to compensate for tool length. OK - I know this won't work for Gene... but may help others. I don't think you will find tap drive R8's simply based on how it would have to be made. But you could buy some 3/4" Drill rod. Chop off a chunk that is the length of the shank and flats. Drill the corners then the center of the drive square and mill a square pocket about 1/4" deep with maybe a 3/32" EM. Turn the part around and drill til it just breaks into the square, then bore/ream to shank size. You would put this drive bushing in a R8 solid Weldon type 3/4" endmill holder. Mark where the set screw would contact bushing then bore a clearance hole with a 2F endmill so the R8 holder set screw is able to clamp directly on the tap shank. Usually long before I have to worry about a tap slipping I have chosen to thread mill. You can buy cheap Chicom import threading insert boring bars that you can grind extra clearance on and mount on center in a ER32 or even 3/4" Weldon that will work for thread milling. There are many ways to skin this cat - but with 9 lives just be sure its dead before you start. Greg ------------------------------------------------------------------------------ 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
