I have been attempting to learn how to run my VM16, which has involved a lot of cutting air.
While doing some MDI operations I slowed the spindle down to 50 rpm and noticed the speed fluctuating.
I reached up and grabbed the spindle and was able to completely stop it's rotation.

I was setting up to notch some tubing so I set it up with a 1.5 dia. end mill and tried to machine the tubing. With a little bit of down force it would stall out the spindle.

Could some one please explain to me why this is happening!!!

Thanks, Dave