Just the post I needed
I was working on the quill last night and was thinking it needed a better way of operation the quill feed.
My mill is similar in style but smaller, it's a Denford Easimill, I think they were a converted medium sized mill.
Denford fitted a very basic feed setup that is a thick plate clamped to the bottom of the quill with a leg sticking off to the side that the ball screw fixes into, the ball nut is in a bearing and is turned by a reduction drive from the stepper.
Problem is that this lump goes up and down with the quill so it often gets in the way on jobs, also I think it's putting extra stress into the ball screw assembly.
I was working on the quill as I have found the Z was not very accurate, it would climb while cutting. After a bit of investigation I found the inner spindle was floating by about 2mm! Yes that was 2mm not 0.2mm.
When I looked into it I found that the bottom screwed ring that is meant to lock the bottom bearing had come undone, I've no idea how this is normally locked but there is a threaded hole next to it that may have had a grub screw for locking it, so I've used this for now. Not very happy with this arrangement as you are relying on a grub screw tightening on to the delicate thread tops.
So I think I'll have a look tonight at altering the feed method and if possible alter it to something like Hoods.
Steve