Well I have been a naughty boy, I have been chipping away at this one without taking any in-progress pics. So now I have a glut of photos to show today. As of today the mill has all three axis' cnc'd and working.
So here is a pic of the Z-axis in place. As you can see I have used a couple of side "cheeks" to hold the Z-axis stepper mount in place.

To attach the Z screw to the top of the mill head casting I chose to turn a M8 thread onto the end of the screw and then use a locknut to grip it tight.
When I drilled and tapped the mill head by hand, some idiot ( me ) drilled the hole slightly off centre, by about 1.5mm
So the solution that I came to was to make a little off-set adaptor,

and secured both adaptor and screw with locknuts.

With that done and the whole mill now working on computer control, I am now turning to looking at converting my Rotary Table.
My RoTab is just a real cheap one, so what I do may not be the way I would do it if it were a more pricey model, but I am just working with what I have.
I started by breaking the rotab down into its seperate pieces, and then I took the shaft that the worm is fixed to and shortened it and turned down a section to 6mm (to fit the bearing and oldham connector).

As you can see here I have left just a smidgen of the 10mm diameter sticking out.

This is for the bearing to rest up against,

Then the oldham connector is attached ( when final assembly is made I will clamp the oldham on the shaft while it is under some pressure, thereby gripping the inner race of the ballbearing which is in turn held up against the 10mm part of the worm-shaft, clear as mud eh? This is hopefully engineered so that when everything is tightened up in place, the worm will be held away from the inner face of it's guide just enough so that it will not bind up (as it had been doing at a certain point each revolution under manual activation) but the bearing will take up any lateral movement, or so the theory goes )

Then I made a steel washer that slides easily over the oldham coupling but butts up against the outer race of the bearing.

Then I turned up an Ali' spacer

The reason for the hole will become clear,

Spacer in place, showing that the hole allows you to tighten and release the oldham coupling that mounts to the stepper shaft.

Then I made a stepper mount out of some 10mm ali plate, This was done via semi-cnc using some of the wizards in Mach3 and also by just using single G-Code commands.
This is the side that the Ali spacer fits into. The outer 4 holes just need to be tapped M5 for the screws to hold the stepper, the inner 4 holes are for threaded rods to hold all the stepper mount pieces together and to the RoTab itself.

This is the side the stepper mounts to, you can see the circular recess for the boss on the stepper, and the 4 large counterbores are to allow clearance for the nuts to tighten the whole stepper mount onto the rotab.

And here is the obligitory mock assembly of the whole lot. I just need to make the threaded rods to hold it all together.

Tim