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 

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.


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