On Tue, 28 Jun 2005 10:39:48 GMT, "DeepDiver"
wrote:


One thing that's still not clear: in my Machinery Handbook, it shows that
the drawbar for NMTB tapers have two threaded portions at the toolholder
end: a larger threaded portion (what they call the "Large End"), followed by
a smaller threaded portion (what they call the "Small End"). Why is the
drawbar stepped in this fashion and how does it work with the NMTB taper
toolholder?

- Michael


Because there are two different drawbar threads commonly used in both
30 and 40 NMTB. I have a number of 30 taper holders that use 3/8-16
drawbar threads and others that are 5/16-hummm 20 IRRC. Then the Cat
30 tapers use both of those and a third, 1/2-12

I have 3 draw bars hanging from a rack on my Gorton MasterMill, for
this reason.

Gunner

"Pax Americana is a philosophy. Hardly an empire.
Making sure other people play nice and dont kill each other (and us)
off in job lots is hardly empire building, particularly when you give
them self determination under "play nice" rules.

Think of it as having your older brother knock the **** out of you
for torturing the cat." Gunner