Thread: How hot to retemper steel?

Originally Posted by HNSB

I have a blade here that has some rainbow streaks on it, presumably from getting too hot on a buffer.

I don't have the expertise to answer your question but if it was my blade I would post a photo for the experts to check out the rainbow streaks. Might be something else. I've seen lather left on a blade produce what resembles over heated steel.

Good call Jimmy. Whatever it was buffed off.

I'd still like to hear from the experts, for future reference.

probably not explicitly possible. edge will burn up, then there's scale. Assuming your piece survives heat treat it will need regrinding so it will be a fair amount smaller .

just so you know; you are still waiting to hear from an expert

different steels need different heat treatment to temper.
What type of steel do you have?I know that Hitachi steels are heat treated in the 700-800 C range, then quenched in Oil/Water.
The process requires precise temperature control or you will not achieve the required results.

How would a person know what type of steel the razor is made out of?
I would have the ability to control the temperature to within about 5-10 degrees F.

Maybe this is something that is just not possible for the amateur?

Originally Posted by HNSB

How would a person know what type of steel the razor is made out of?
I would have the ability to control the temperature to within about 5-10 degrees F.

Maybe this is something that is just not possible for the amateur?

Not sure about the steel, but if you have to go to 700C that is 1290 F, you need a special furnace for that.

Mike Blue or Butch Harner could certainly tell you. Maybe shoot one or both a PM in case they haven't seen the thread.

Originally Posted by HNSB

How would a person know what type of steel the razor is made out of?

They wouldn't. Seriously.

Originally Posted by HNSB

Maybe this is something that is just not possible for the amateur?

Indeed.
Also note that razors are ground after heat treatment because the blade needs to be solid enough to survive the thermal stresses of rapid cooling (among other things).
A hollow ground razor will not survive this.

i ll have to get a pic of what razors look like in my shop before heat treat

i can tell you this cause of the soak times in my kiln i only part grind and leave the edge around a nickle thick
if there is any warp at all i can grind it out
and remember there is less good steel after heat treat cause of decarb (less you run salt pots) so leaving a bit to grind away is a good plan

yes its a bit harder on belts and takes a bit longer over all to grind but at least you get a finished blade