[brushlessboy16]

Originally Posted by Ryu James

i dont think i have a torch that would turn this gear red. what kind of gas?

you need carbon to harden steel...

You heat it up until it is red and non magnetic (going to have to check) then clench it in oil. then heat it back up and clench in water.

Using just water DOES case harden but not as well as added carbon.


See here
http://www.technologystudent.com/equip1/heat2.htm