Move knee or quill?

[jackfisher]

I'm just getting ready to convert my Bridgeport series 1 to CNC with stepper motors and I can't decide if I should use the knee or the quill for my motorized Z axis. Could some of you fine folks give me some input as to which route I should go and why one would be prefered over the other?

Thank you

Jack Fisher

[keebler303]

quill is preferred as you are moving a few pounds instead of a few hundred. So the quill motorized would mean smaller motor, better acceleration, better all around performance. I would also suspect that the quill has less runout than the knee with the slides unlocked.

My $.02
Matt

[colin1544]

Hello Can I put my two pennyworth in the quill is more controlable and much more sensitive for small step movements using the knee you would need to have the gibs set up very precise especialy when doing drilling operations I previously had a Bridgeport series II NC which had a air assisted knee and the whole knee saddle and bed plus any fair sized job must have weighed close on 1200 lbs and to see it doing a drilling operation with pecking was quite scary when doing the rapid moves up and down so it would also be better on the nerves. Cheers Colin