I keep a lot of counterbores.
You aren't really fitting saw screws / medallions without one. Plus a 
lot of other jobs.

    The aircraft industry uses a lot of them so hunt in the town where 
they make airplanes.
They practically give used ones away.
You'll have to resharpen but sheesh thats 40 seconds out of your life. 
hahah
They are very easy.

I silver soldered a brass plug to the end of a spade bit once, for a 
really oddball counterbore I needed to make.
  I can dig it out and take a pic but it looks just like what you 
thought it would look like.
   yours scott

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*******************************
    Scott Grandstaff
    Box 409 Happy Camp, Ca  96039
    scottg@s...
    http://www.snowcrest.net/kitty/sgrandstaff/
    http://www.snowcrest.net/kitty/hpages/index.html