Seemed to stand up well enough, the bolt went through the bracket that clamped to the ball nut, I had a recess in this and I made a brass insert to go between this and the quill, the insert fitted into the recess in the quill. Once it was all cranked up it was very solid and never slackened off in the two years I used it.

Hood

I thought it looked a bit bigger than 1/4-28. That does seem kind of light.
RC

Mine has a 3hp 3phase motor , I am using a teco 100 vfd and leave the belt on the pulley one down from the top . Allows the spindle to run between 800 and  3000 rpm , it also has a slow speed set of windings that run the motor at half those speeds, can also  switch into back gear for slower speeds which I have only done maybe twice .

also has a pretty big flange on the motor, aprox 10" in diam ,  I have seen a website where the fellow makes an adaptor plate and fits a 90vdc spindle motor

RC,
  Looks like your good to go now. I just knew Hood would come through.

Hood, what's  the power draw bar setup you have on that machine? Looks good.
 
 Ed

Ed that mill is long gone to the scrap man The power drawbar was nice, its an Aussie Power Drawbar.
Hood

What does mean this "Aussie Power" ?
Runs on  kangaroo  s**t ?

Nope, I got mine from the USA so it runs on hot air
But it did spring up and down like a kangaroo

Hood

 
With the proper "plumbing" I suppose it could be run with METHANE as well.   
RC

just make sure there are no leaks

Hood

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