On Tue, 5 Jul 2005 11:30:15 -0700, Harold and Susan Vordos wrote:

"Dave Hinz" wrote in message
...
OK, I now know several ways not to do this. Sounds simple - 4 holes,
evenly spaced, around a circle 0.600" in diameter.

Do you have a mill?

Couple of 'em.

If so, trig the dimensions and do it by starting with the centerline of the
part, established by dialing it concentric with the spindle. That way you
can drill any conceivable hole pattern without any special tooling.

Well, I thought of that too. I have a rotary table for the mill, and if
I could have figured out a way to hold the piece on it, I could just
find the center, go out 0.300", and poke a hole at each of 0, 90, 180,
and 270 degrees. But, what I have is more or less this:
http://www.sherline.com/3700inst.htm
....and I don't have anything to mount a chuck to it in the center.
Holding is the problem. For the lathe work, I drilled & tapped a hole
in the center for a bolt (which I needed on the finished product - I'm
making a sort of spanner wrench to be turned by an open-end wrench), and
located by using the 3-jaw chuck in the lathe on the head of the bolt.

Needless to say, you must be able to hold your part vertically. If it's
too long to get under the spindle, this method may not work. Be sure to
keep backlash always in the right direction if you don't use a DRO.

I don't have to worry about DRO on my mill

Thanks,
Dave Hinz