New lathe chuck key

[Dell]

Hi all happy new year
I twisted the square part of my Pultra four jaw chuck key (it’s only 5/32” ) so have to make a new one or two, been trying to find some EN19T but all I can find is 1/2” a bit to big I think , anyway in the mean time I have made one out of silver steels, I know I have to heat treat to cherry red quench, clean up then heat to blue and quench but quench in oil or water.
Dell
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[borriss]

Hi Dell.
Happy new year to you.
I make all my chuck keys out of socket head cap screws. Just turn and mill, no need to heat treat. Cut off the socket and cross drill for the tommy bar. Cheers Borriss.

[philf]

I've made several and have always used silver steel.

I quench in vegetable oil. (Used oil from the deep fat fryer.)

You still need to temper them after quenching.

Phil.

[Dell]

borriss
Thanks I have ordered a couple of bolts but will I be able to mill with HSS or do I need to get some carbide endmills.
Phil
Thanks I will use cooking oil on the one I have made, I think the fact that the square on the key is only 5/32” doesn’t help strength wise.
Dell

[borriss]

Dell.
HSS steel is fine. Slow speed and plenty of cutting oil. The bolts are tough not hard.
If you use silver steel check whether it is oil or water hardened and heat treat accordingly.
Cheers
Borriss