On Wed, 15 Dec 2010 22:14:32 -0600, Ignoramus22945
wrote:

On 2010-12-16, wrote:
A Fanuc Robodrill (CAT 40 VMC) will peck tap 1/4-20 UNC holes at 10,000 RPM.
That's not just me.
Your mileage won't vary.

I don't doubt that at all...I am, however, using a fairly old Hurco
that couldn't spin that fast with a bullet at the set-up dudes
head....that's me, by the way.

And the reason for the 2500 speed is that that is all the faster the
head is rated at. I have a smaller one that I use for taps #10 and
under that will take up to 4500.

At 10,000 RPM, a 20 TPI tap would travel 8.33 inches per second.

At 2,500 RPM, 2.08 inches per second.

i

Yeah, about that...one job I do fairly often involves a ew hunderd
#6-32 taps 7/16" deep...

....I spin at 4000 RPM and the feed is about 115 IPM. Perfect world
number is 125 IPM, but I always run the feed just a bit under nominal
so that the tap is always pulling a bit....less chance of
crowding...and the clutch will take care of the rest.

Mike