I need some help retrofitting modern controls on a Bridgeport Series II Mill

Hello,
I am new to this group and have read some of the old threads regarding
retrofitting a windows based controller and re-using the steppers and
one of the power supplies. Alas I am still clueless and need some
guidance.
The machine is a 1975 BP Series II NC with a seperate BTR (tape)
cabinet and as far as I can tell the steppers are NEMA43 12A with
about 600 on the holding torque (please correct me if i am wrong). I
was wondering what drive would be suitable for them. I presume the
gecko's are too small looking just at the amperage, or maybe they
would be ok at the unregulated 56V from the original power supply. I
read about someone building a regulator and re-winding a transformer
for higher voltage??? I would appreciate any help as to how to do this
and what the advantages and disadvantages are.

Thanks in advance,
larry@...