Quote Originally Posted by John S View Post
Not easily done just by the heating and quenching as the screw will almost certainly be low carbon steel.
The only easy way to do this is by pack hardening in something like Kasenite which makes a mess of fine details like a tap, hence the reference to molten cyanide.

If you fancy going this route, buy an extra 150 to 200 mm length, send it up and I'll flute it and get it hardened in with the next batch of gear that goes over.
I'll make two, you get one back, I keep one for payment.
Now thats a deal John!

I was looking at Kasenite and similar stuff. It does say in the instructions that its ideal for one-off, low-use tools such as home made taps... but I can see that the fine detail might be problematic...

The company I talked to re cyanide hardening needed to know exactly what steel was being used and its exact composition else they couldnt harden it... I wonder if MD have that data? I'll email them...