If I had to do this:
Assumptions: 4 pieces, +/- 1/32" or better
*MIG tack weld the 4 together
*Use centering head on a scale and scribe a diameter line on top disk
*Prick the first and oposite hole at .5" from the OD on the diameter line.
*Set your divider/compass to 2.12132" swing the divider/compass from both
pricks to mark the other holes. Prick and follow with a bigger centerpunch.
*Use a combined drill/countersink or center drill then follow with drills up
to size.
*Grind open the weld to free the disks.


wrote in message
oups.com...
Hi,

thanks for reply,

Holes need to be drilled on outer diameter of
the metal discs, 4 of them. They all need
to be 1.5" from the center of the discs, at
0,90,180,270 degrees (a square)

problem is the discs have a 1" hole in
their center, so a compass cannot be
used to locate the center of the holes
that need to be drilled.

I don't know what to measure off of.

I will go upload drawings to dropbox
now.

Thanks,
Rich