Good point about a rod. I just might machine up a centering rod before
spotting my large drill bit on the radial arm.
I always tack three or more bars across the sides of the plates. I hate
people who tack directly. Listening to me rant about their ignorance while
trying to break plates apart is not pleasant.
My guess is that I will not see the plates drilled in the machine shop
until long after I have drilled my plates.
Randy

"Randy Replogle" wrote in message
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"Randy Zimmerman" wrote in message
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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




Can the machine shop spot or center drill the top plates of each set? You
could chuck up a 60 deg pointed rod to locate each hole. Can someone tack
weld the plates together to prevent movement?
Randy