Ignoramus30138 wrote in
rec.crafts.metalworking on Fri, 17 Dec 2010 09:16:06 -0600:

By the way, forgot to mention. I have three aluminum plates that are
approximately 12" wide, 30" long, 3/4" thick, and have handles on
them.

I wanted to drill a rectangular set of tapped holes in it, probably
1/4-20 holes on every inch of a 10x24" area, so it would be 240 holes.

I have a theory that then I could sell the plates for big bucks, as
layout/fixturing plates.


We do that at work all the time.
We start with a grid of 1/2-13 helicoil tapped holes.
Brass plugs are made that just fit flush to the top.
The whole thing is fly cut to true-up the surface.
Helicoil inserts are added as needed to hold parts, vices fixtures
etc.
Different plugs are used to block off holes that have the inserts in
them.

Wouldn't anyone that would need such a plate be able to make it
themselves anyway?
--

Dan H.
northshore MA.