I bought a VERY old heat treat oven quite a long while back...

I'd like to check that it is reasonably calibrated before heat
treating this part. Is there some sort of thermocouple and high temp
wire I can buy and take a voltage reading? I only know of this
concept, not any specifics.

I made a custom bolt out of 4340 for my 30 ton shop press. Looks like
I should heat to 1525 and quench in oil. Then temper to 450. correct?
I'll use SHMBO oven for tempering (when she goes shopping)

Karl