Hi All,
Being unhappy with the state of the cross slide on my Myford ML7 coupled with my preference to work metric I decided to make a metric version of the lead-screw and replace the mazak nut with a Phosphor Bronze one.
Whilst I can quite easily cut a 12mm x 2mm extenal ACME thread the nut would present a number of problems, not least of which would be the measurement - I know I could simply use the lead-screw to test it on an empirical basis but that is inherently unsatisfactory.
My idea is to cut the lead-screw (165mm) plus an extra length (70mm) which I can then flute and make into a tap. The length of 'FULL FORM' would be 15mm with 3mm at core dia., 45mm tapering and 7mm of 8mm square for the tap wrench.
Once the turning is complete and the 'tap' section separated from the lead-screw, the tap will need to be hardened of course (after fluting).
My only experience of hardening was some 45 years ago and entailed serious heat and cyanide baths amongst other similarly dangerous environs.
The material I already have on the workshop shelf is EN1a.
The questions are :-
- Am I wasting my time using EN1a?
- Can I harden EN1a in my workshop with access to only a blow-torch/5.6Kw Gas-Ring and a bucket of water?
- Should I use Silver Steel - with the possibility that the tap will not be 'exactly' the same size as the lead-screw (ie. machined as a separate component)
Bear in mind that it will only be needed to cut the one Pb Nut.
Thanks in anticipation.
JG