[TheForge] First hammer heat treat foolishness....

[Mike S. via TheForge]

Learned a few things about an oil quench…
First and foremost is that I need more oil!
A gallon is not nearly enough for a hammer head, I’ve done acceptable 
harden/temper treatments on knives and punches with just a large soup 
can of motor oil or ATF.
A 3 lb rounding hammer, not a chance.
The oil (motor) boiled up to the rim and the bucket got well over 100 
degrees.  Hammer head was too warm to touch after the second quench of 
the second face, but OK to hold in hand with the rag I was wiping the 
oil off with. It took not quite an hour sitting on the anvil to cool to 
the touch.  The faces are hard, but a file will bite at the eye.  Going 
to grind and polish the faces this weekend and once I get enough oil,  
seeif a MAAP torch in the eye will transfer the heat needed to bring 
the faces to dark straw color.

A couple of questions.

How much oil is generally needed to quench a hammer, 3 gallons? 5 
gallons? Heading to the ArmyNavy store to look for an ammo box to hold 
it, and

With 3 lbs of 4140, is an oven temper at 400 or 425 for a few hours a 
workable solution to tempering this hammer?

I’ve also got a burnout furnace, used for firing small scale ceramics 
that bottoms out at about 400 and will sit at 800 or 900 degrees pretty 
consistently.

Considering how long it took the hammer head to cool down, could the 
residual heat in the steel have effectively tempered the faces? (Long 
shot, I know)

Thank you,

Michael