It sounds to me like what you need to do is get or make your self a transfer
punch. This is a center punch that fits snugly in the hole you are trying
to match and allows you to mark the center on the second plate.

Have the machine shop turn some 13/16 plugs with a hole in the center that
will match the diameter of a transfer punch.

Set the master plate over the other plate insert one of the plugs and center
punch the hole location. Drill that hole to size and then reassemble with
the master plate. Align the hole you drilled with the hole you marked it
from and insert a plug through both the master and the copy. Mark your
second hole and drill, reassemble and continue till all the plates are done.
Doing one at a time will be slower than marking them all at once, but it
should get you dead on that way.

--

Roger Shoaf

About the time I had mastered getting the toothpaste back in the tube, then
they come up with this striped stuff.
"Randy Zimmerman" wrote in message
news:E7Azd.594424$%k.181706@pd7tw2no...
I will be drilling some plates with holes around 13/16 that have to match
up.
The bolt hole pattern is for eight holes on three different plates that
have
to
match. From what I understand there will be 26 sets of three. One set if
the three will be done by a machine shop and the rest are my
responsibility.
I am thinking of an accurate scribed layout, pilot drilling and
drilling
one plate to use as a master before stack drilling. The plates are around
3/4 thick. Any suggestions on how to make locations more accurate??? I
am
limited to a radial arm drill press. No milling machine. Edge distance
are
not critical but hole pattern is.
Randy