Can't get lathe to Feed

Theoretically you could get 2 PPR with 1 A+Z pin (and a 1/2 disk encoder wheel)
if the encoder component could be taught to count rising and falling edges of A

There are also some of the magnetic encoders that use PWM for absolute 1 turn data

You are correct Andy. A CNC lathe with no screw cutting partly defeats the point. So I'm going to pull my finger out and sort it out. There for I'll start a new thread on this subject.
I see that recently there is a thread 'Threading on a Boxford TCL lathe' which will be useful, but starts a little bit further on that were I'm currently at.

Nick..

I haven't dealt with the Tool Changer yet. That will be my last task.
I'm not looking forward to that particular problem

Yes I'm in the UK
Nick

There is no feed back from the ATC.
It's a simple stepper/worm wheel arrangement.
The indexing is locked via eight 45degree notches and a ratchet pawl.
Stepper indexes 45 + say 5 extra forward, then back 5 to hold against the ratchet.
You have to teach the initial 'Position 1' as a 'home' postion.
I have considered making an encoder wheel with three proxy sensors, but space is VERY restricted, as the tool turet is tiny.
The ATC will have to be dealt with later after I've sorted out the spindle & G76 encoding. At least if I add an extra parallel port for my spindle I will have the available inputs to handle the ATC encoder if I go down that route.

Hey Andy,
I'm teaching you to suck eggs here!.
I've just looked at the HAL carousel componet (Which I never knew existed)
and its been written by a guy called Andy Pugh. Thats a coincidence, because thats your name as well !