Rendering, an explanation...

[BSimon1234@AOL.COM]

Brian:

Thanks for the clarification. 

<< This is special bit used on metal lathes  to make an indentation in the 
end of your stock so it can be placed in one of  the centers>>

I do a bit of machining, and I do now know what you are talking about, but 
generally see them as  "combined drills and countersinks" or "spotting 
drills" in the big MSC catalog. Apparently, "center drill" is the lay term.

Since you elaborated, my catalog lists a  #7  as being a 5/8" body diameter, 
1/4" drill diameter. Does that sound right to you? Are you grinding the drill 
point away down and  using the fat body as a hand tool?    A #2 size has a 
3/16" body and 5/64" drill, - would this be closer to the size you might 
chuck in a battery operated drill? 

<<look closely at the inner  contour of the hole/face in the agraffe.  Take 
the agraffe to your favorite  machinist, and have him/her grind  to the same 
contour.>>

Another list member, Mr. Hunt - I think,  mentioned recently that there was 
generally a 1/16" radius on the brass ring around the hole in the agraffe. 

If one does have one ground, you might as well go with solid carbide. It is 
only a few bucks difference and with brass it will last a lifetime without 
sharpening.

Thank you for clarifying things.

Bill Simon
Phoenix