On Dec 17, 4:01*am, Tom Gardner mars@tacks wrote:
On 12/16/2011 11:53 PM, wrote:

Last night on my little Rockwell 21-100 mill, I was changing the radius on the underside of rifle scope base with a boring head.

As I raised the knee, there was cutting close to me, and then as I lowered the knee there was a new .001" of cutting on the mill side.

Is my vise too heavy? are the knee gibbs loose?
What is going on?

TIA

Is your mill aligned properly with magnetic North? *Did you account for
deviation?

Could you possibly give a more useless answer to a genuine
metalworking question?