Stealth Pilot wrote:

apart from having the tool exactly on centre height, sharp edges to
the cutting tool, and experimenting with cutting speeds there are no
other tricks to getting polished threads at 7mm x 48tpi are there?

7mm shouldn't be a real challenge. Or is it the mix of imperial and
metric? :-)

HSS bit, experiment with cutting oil, supporting with a live center.
Other things that have some influence:
Clamped top slide, cleaned bead and lead screw all freshly oiled and moved
back and forth a few times. Slightly clamped saddle.


Nick
--
The lowcost-DRO:
http://www.yadro.de