"Lloyd E. Sponenburgh" wrote:

"Pete C." fired this volley in news:4d365f7a$0$14607
:

Considering that these are "knee" mills and in their manual form are
intended to use the knee as the primary precision Z axis, I think you
are way off base thinking that the knee needs to be locked.

Pete, the little training I have had taught that the knee shall _always_ be
locked during machining. I'm not sure why the locks would be there at all,
unless they serve a functional purpose.

LLoyd

That's bad or misinterpreted training. The knee is your Z in normal
manual machining, not the quill and you have to have it unlocked to do
any machining with a Z move. What you may be misinterpreting is the
recommendation that you lock and axis you aren't moving for a particular
machining operation, which applies to X and Y as well. Locking any axis
you aren't moving will increase rigidity by locking out the backlash in
the axis, as well as protecting it from you accidentally bump the handle
when reaching for something.