Opps, didn't see the depth criteria in the original message. The only
other thing I can think of short of a milling machine and endmill is a
spur type bit or what B&D calls their bullet drill bits(I think) and
that will leave a small hole in the middle, and they would have to be
modified a bit to give you a flat bottom.
You may be able to get away with a 4 flute endmill by using a drill
bushing in a jig, but that could get a little costly and you might be
better off subconstracting it out.

Harold & Susan Vordos wrote:

"James P Crombie" wrote in message
...

Marty
Drill your 7/8 hole with a regular drill to the proper depth. Then
uses a reground 7/8 drill with flat bottom. It will need a relief gash
in the center to enable it to cut properly and I would put a small
radius on the corners of the drill to prevent chipping.



Sadly, while your suggestion is a good one, one that I have used for the
bulk of my years in the shop, it won't work in his case. The size of the
hole versus the depth won't allow for it.

Harold



--
--------------------------------------------------------------------------

James P Crombie

Summerside Machinist
Prince Edward Island Amateur Astronomer
Canada 3D Designer

E-mail
Astronomy webpage http://www.jamescrombie.com
Rhinoceros 3D webpage http://www.jamescrombie.com/rhino/
Mirror Grinder page http://www.jamescrombie.com/pics/
--------------------------------------------------------------------------