On 2010-12-17, Pete C. wrote:

Ignoramus6780 wrote:

At this point, after adjusting the base period, there are no more
following errors. It seems that, in the straight gear, rigid tapping
works just fine.

I have not tried it with real material, yet, but will do so as soon as
practicable. I am not expecting too many surprises, especially with a
floating tap holder.

Based on some calculations involving horsepower, torque, and tapping
torque requirements, I have some numbers to work with.

3 HP at 500 RPM gives 31.5 ft-lb. After adjusting for transmission
losses, I would say that I can easily have 20 ft-lb available for
tapping at 500 RPM.

According to

http://www.parlec.com/pages/tapping_...rements_speeds

In steel, I can tap up to 9/16" in steel and stay under 20 ft-lbs, and
up to 7/8" in brass and stay under 20 ft-lbs.

So, my back gear reversal issues, really, are of minor importance if I
do not tap in back gear. I rarely tap anything over 1/2", so I can do
most of my work in the way I am set up right now.

i

Try tapping some machinable wax with a moderately large tap like 1/2-13
so if something does go wrong it's more likely that the wax threads will
rip out vs. breaking a tap.

I wrote some code, will execute it a little later, probably in wax
first and then in steel. I will try to shoot a video.

i