Tapping success!

I decided to try tapping with Mach 3 today using a tapping head.
Several months ago I purchased a Procunier size 3 tapping head on
eBay for $90. At the time I had no idea how big a size 3 was. It
turned out to be huge. I just put it in a drawer and forgot about
it. Fast forward to this weekend. I decided to make a welding table
out of a 35"x15"x1" piece of aluminum with holes drilled and tapped
on 2" centers. I had made a similar plate for my mill while I was
taking a CNC class and had use of a Haas CNC mill. This time I would
use my converted Bridgeport. Due to the size of the plate I had to
drill and tap it in 4 quadrants (after tig welding 20 holes closed
that came in the plate and surfacing it).

I used a G73 peck drilling cycle for the holes and then just G1 and
G0 moves for the tapping. The Procunier tapping head reversed at
twice the RPM as the feed. I was running it at 210 RPM to it would
reverse at 420. I have read that I should feed it at 95% of the
calculated feed rate to account for any possible slippage or slop in
the system. I used a forward feed rate of 15.2 IPM and a reverse at
30.4 IPM. The size 3 is so large that it took all but the last 1" of
my knee travel to clear the table. I am always nervous any time I
try some new program but everything went perfectly. The holes were
drilled at a rate of 1 every 36 seconds and the tapping took 12
seconds per hole. There are 112 holes in the plate. I posted a
video here:

http://www.flyingcritters.com/video/Tap.wmv

I know some people will cringe at using WD-40 for tapping fluid, but
it works for me. The ½" tap I am using has tapped over 250 holes 1"
deep and it still looks sharp.

Vince