On Wed, 22 Mar 2006 22:48:23 +0000, wrote:

Centre drill are often used as spotting drills in the lathe
but there's a pretty wild mismatch between center drill point
angles and the the usual jobber drill that follows. Special
spotting drills are produced for NC use at about three times the
price of similar centre drills.

How do the special features work and are they worth the
premium price? Some seem to be single flute designs and the
included angle is usually less thqn 118 deg jobber drill angle.

What's the experience in using these items and what's the
reasoning behind the design differences?


As others have said, I like spotting drills a lot. I use them in a
variety of CNC machines - mills, lathes, and screw machines. I used
to pay the big bucks for expensive NC spot drills, but I recently
ordered a few 3/16" NC spot drills from Western Cutting Tool for $3.86
each. They actually look pretty good, and I have had no problems with
them.

--
Bryce

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