I bought a couple of 3/4" thick aluminum fixture plates.

http://igor.chudov.com/tmp/Fixture-Plate.jpg

It was a local sale.

I would like to drill and tap them with 5/16" drill and 3/8" tap, say
spaced at 1" interval. That makes for about 200 holes to be drilled
and tapped on my CNC mill.

Some questions.

1. What is the best way to drill aluminum with 5/16" drill bit, making
through holes. What RPM and feedrate and how often to peck.

2. Do I need to center drill those holes first? It is not really a big
deal, just some more G codes.

3. For tapping, can I safely use a ER colleted floating tap holder that has a
little bit of vertical internal travel. Like this one:

http://www.maritool.com/p67/ER25-Flo...duct_info.html