On Sun, 26 Sep 2010 21:24:40 -0500, Ignoramus24898 wrote:
On 2010-09-26, Karl Townsend wrote:
On Sun, 26 Sep 2010 16:41:07 -0500, Ignoramus24898

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

By chance I just finished drill and tap to 3/8 on four holes in AL 1.25"
deep. I used G81 (no peck) feed 5.1 speed 2100. Got thick chips that fed
out well and broke every two inch or so. Used my coolant mister at a
heavy flow.

Pretty cool. You feed 5.1 is how many inches per second?

Someone suggested 0.4 IPS, which makes some sense to me.

This makes me wonder: Is there a machine where a machinist could make
one part "by hand", i.e., in the normal way you'd use a regular mill
or whatever, but where the machine could record the machinist's actions,
and then "play them back" for the next part? Or is it only possible to
drive an NC by writing a string of textual commands?

Thanks,
Rich