"Michael A. Terrell" wrote:


Add an encoder on the spindle to read the actual speed and use that
to set the timing, then the processor generates the drive in sync for
whatever ratio you need. Not as ridgid as gears, but will let you do
small jobs OK.

Well for threading
You also need to be able to sync not just to spindle speed, but to
spindle position, unless you are going to cut that thread in a single
pass. Thus you also need an index pulse.
jk