This is a 38 year old Atlas Clausing Vertical Mill which I rebuilt and converted to CNC 4 years ago.
Six speed ranges / 24"x 6" table / 15" x 5.25"  cross travel / MT 2 taper in spindle.
The guard is removed to show stepper mounting. A handle extension was made for the quick feed
( in-out to engage fine feed) and a 85 in oz stepper was mounted directly to the fine feed, thus total manual
operation is still available. Motor side of the x and y axis have double contact bearings in the bearing blocks
with a single contact bearing in the other bearing block. Nuts at handle ends provide for preloading adjustment of the bearings.
200 in oz Superior Electric steppers on the X and y axis. Three axis digital display along with an indicator for quill movement. Not much room for the ball nut as shown by the picture. Ball screws 16mm -5mm lead with adjustable ball nut by Techno Inc. A 1 HP DC motor with variable speed controller still waites for me to installation.
Overall dim of 36"x 40" x 70" provide for a nice homeshop mill.

Nice Rich, Good job.

Brett

I TOTALLY agree....Excellent Work.
Thanks RICH,
RC

Very cool, Rich, thanks for sharing the pics - 

Pic of the mill head modified such that the quill movement is done with a ball screw. Need to make a cover and reduce the 0.001" backlash.
RICH

The mill served me well until I got into 3D miling and it just would not do the job.
So improvements to the mill were required.
I reworked the  the X and Y bearing holders and installed new and better bearings, upgraded the stepper motors,  and per
the last reply modified the head to use a ball screw to drive the Z axis.

What a difference to have no backlash and all the axis can  now can do 80 ipm reliably.

I attached the old adapter plate for the high speed spindle  and tested her out....machine worked  like a charm.

RICH

Rich, how fast can that high speed spindle go?

The one pictured is 18000 rpm / 1/4 hp.  The Dumore  is 12000 rpm under load and also 1/4 hp. Have others that are air driven that go to 60,000 rpm.
The spindle holder gets up to around 105 F so maybe the spindle is around 110 to 115F after an hour of use.
May need to make a water cooling jacket or add air blowing on it since it will get somewhat warmer when cutting SS.

RICH

Rich

Beautiful machine. You should be proud.

Eric

Very useful and very flexible, and saves writing programs for odd jobs if you can still use the old handles. Well done