"Pete C." wrote in message
ter.com...

Ignoramus30138 wrote:

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.

i

Remember that 1/2-13 hold down hardware is the norm for Bridgeport sized
machines, so 1/4-20 wouldn't be very popular.

The 1/4-20 holes on 1" centers are standard for optical breadboard
breadboard plates like those below. They do sell for big bucks retail, but
the problem is marketing them to a limited clientelle. On ebay,
lightly-used plates go for about a third of new prices, but then at those
prices you have to ask if it is worth your time plus the cost of aluminum.

I saw a video once of how they make this table tops. They have a massive
array of multiple spindles that drils and taps all the holes at once in a
few seconds.

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