"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.

We'll assume that each set of three only has to match itself (this is *very*
important.)

I would take one plate that the machine shop has done and use it as a master
template. Make or buy a transfer punch of the appropriate size. Clamp and
punch 26 blanks using the master and the transfer punch.

Now, simply clamp (I also like the idea of welding them) two unpunched
blanks to each punched blank and drill together.

From my experience, the fixturing on the radial arm is going to make or
break your profit margin. You need to be able to clamp/unclamp your part,
and index it to the next location, very quickly. I wouldn't reposition the
head on the press unless the plates' size prevents them from being moved
between holes.

Also, make sure you don't have to spend a lot of time clearing chips/coolant
as this will make the job much longer. Using posts or blocks to raise the
part off the table will help this issue (perhaps 2"+). Make sure there is
lots of support around the hole being drilled as you don't want anything to
move.

I would also suggest splitting the point on the drill and popping the hole
in one shot. You should be able to get a straight hole although you may be
inclined to peck the drill as this will help the location.

HTH.

Regards,

Robin