Tumbler hardening/tempering

[sherpadoug]

I had to make a new tumbler for a flintlock musket. The new piece fits and works well but it is made from O-1 oil hardening tool steel which is still quite soft as I haven't hardened it yet. I have an electric furnace (small pottery kiln) so I can heat it to 1500F and oil quench to harden it.

Would that leave it too hard and subject to chipping? Does anyone have experience with O-1 or have a feel for how deeply I should temper it?

Buffalo precision has a table on the web of O-1 temper temperatures vs Rockwell hardness but I have no idea what Rockwell hardness I need for tumbler.

 

[LRB]

Yes. It would be too hard and too brittle. A double 1 hour each temper, at 400°/425°, gives 01 it's optimal balance of hard tough, and should be at about 60 Rc tempered at that heat. 01 really should not be heated beyond 1475° for the hardening procedure. Going with a higher temp offers more chance of grain growth, and a slightly weaker structure with slightly diminished wear resistance.

 

[ZUG]

Listen to what Wick has to say -- he is always "spot on" with his hardening/tempering of O-1 + others steels. :thumbsup:

 

[sherpadoug]

Thanks, That is my project for this evening.

 

[dave_person]

Hi,
Hopefully, your sear is the same steel as the tumbler. I always harden and temper sears and tumblers together using the exact same regime so they are equal in hardness and one does not wear the other.

dave

 

[sherpadoug]

The sear looks cast or forged. This is not a high quality piece and I have no idea who made it. I am at least the third owner.