Been playing today

A while ago I cleared a local college's machine shop out when they
closed it down.
Usually Health and Safety issues, plus they can get more computers
into the same space than machines. Only good point is they are
teaching Chinese students computer studies [ if you can't beat them,
join them ! ]
Anyway I sold a lot on but kept a few machines back for my own use.
Amongst this lot was a Myford ML10 lathe converted to CNC.
Hardy used but very dated with a BBC computer on it.
Tried it when we got it back a while ago but it errored out for some
reason.
Had a look at it and discovered the motor DC spindle speed board was
lacking the logic voltage. Traced it thru and found a dead
transformer, replaced this this weekend and decided to give it a
whirl.
The program as written in 1986 in BBC basic but it must have been
quite advanced for it's day.
It uses a spindle encoder for threading but it also uses the same
encoder to check for non starting and stalls, hence our original
fault. It uses standard G code and the usual lathe canned cycles. It
also has a simple graphical simulator and can check for collision. As
I say it's quite advanced for a 1986 program. Ran a few collets off
for the little Taig mill and did a bit of test threading.
Once I got a few operator errors sorted I tried to do a 1/2" x 10 tpi
Left Hand Acme leadscrew.
Very impressed with the way it did this but I'm certain the accuracy
isn't consistant due to the lack of a traveling steady on a long [
13" ] thin screw such as this.
Shows what can be written for control software for this to be in
basic and on 1/2 of an old 5 1/4" disk

John S.