On Thu, 08 Apr 2010 09:33:54 -0500, Ignoramus16651
wrote:

On 2010-04-08, Joseph Gwinn wrote:
In article ,
Ignoramus8052 wrote:

On 2010-04-07, wrote:
As the others have said, the shanks are soft. Just don't leave a
sharp corner where you turn the thing down, if the drill jams up, it
could leave you with a twisted-off shank in the chuck and the drill
stuck in the work. That's if you've got a drill that can wrap you up
if it jams. Some of the cheapies will just stall out.

I have two drills like that, that could twist my arms. I prefer using
the less powerful drills where possible. It is a very unpleasant
sensation. The application is to enlarge a 5/8 nominal hole to become
a 21/32 hole, and to later tap it for 3/4-10 thread.

What is the material being drilled? Steel is guaranteed to grab and make the
drill try to tear your arm off. Cast iron would be easier, if the drill is
dressed as for drilling brass.

Cast iron


This is actually to move that Bridgeport Interact II.

Why is 5/8" too small?

The hole is 5/8". I need to tap it for 3/4-10. Thus I need to enlarge
the hole to 21/32.

Is there sufficient remaining meat around the hole if it is enlarged?

Yes.

i
Just chuck the drill up and turn the shank. Then grind a small (say
1/16") flat on the cutting edges In other words take out all the side
rake on the cutting edge (look at the cutting end with the shank up)
just as you would if you were sharpening for brass or other soft
material. Then have at it.

What is it that Nike says?

Cheers,

John D.
(jdslocombatgmail)