I'm not sure if it's practical but you could use a thread mill and a helical
interpolation. Thread mills might be too expensive but it's interesting
anyway!

RogerN


"Ignoramus8473" wrote in message
...
OK, so I have a CNC mill, in which I know the spindle speed only
approximately.

Can I, realistically, use it for threading through holes, perhaps with
tapping head?

i