DIYbanter - View Single Post

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?

Jim

You can get spotting drills in both 90º and 120º angles.
The main advantage is the robustness of the drill.
Longevity far outweighs the cost especially using TIN
coated spotting drills. I love em! :-)

Tom