Tempering Striking End

[petek]

In a previous question I asked a few beginner questions about heat treating tools in a kiln - the advice given was extremely helpful.

One more question, if you all will indulge my desire to use a heat treating oven for as many steps as possible...

I've been experimenting with hardening and tempering my striking tools using only the oven and quenchant. This has been working great with the exception of producing a tool with a hardened striking end... a problem on a number of levels. I may have found a solution to this, but would like to run it by the experts here for a critique or suggestions.

After tempering I've stood the tool up in a shallow metal dish with about half of an inch of water in the bottom, submerging the "business end" of the tool. Then in a darkened shop I've used an acetylene torch to slowly heat up the striking end of the tool to a very slightly red color (just off black) and held it there for a couple of minutes. Then allowed it to air cool, with the part that I want to stay hardened still under water. The thought being that I am not getting the tool over the critical hardening temperature with the torch but the heat should severely temper the striking end and the water should prevent further tempering of the part that I want to remain very hard.

This seems to be working and filing the struck end "bites" a bit...

Do I have a good procedure here, or is it back to the drawing (no pun intended!) board?

Thanks!

-- Pete

[pkrankow]

That is one way of doing it!

You can heat with any source, and then stand the business end up in the water while it is still cool, if you wanted. This is very similar to running the colors.

Phil

[bigfootnampa]

It seems to be working and I can't see why it shouldn't. I'd just stick the struck end into my coal forge and bake it a bit while leaving the working end out of the fire (though I actually do it the other way round... only hardening one end).

[forgemaster]

We would normally (depending on the size of the tool), heat the stuck end of the tool with the oxy torch till a dull red, then place it hot end downwards into a bucket of sand to cool out slowly, or we make a mound of dirt and shove the hot end into the dirt to cool slowly. This method depends on the size and lenght of the tool, if it is too short yes the heat can run back and pull the temper out of the business end of the tool. Covering the heated end just help to slow the cooling rate, some steels can air harden fairly easily, especially if the heat gets sucked up by the body of the tool.

Phil

[Rich Hale]

For folks new to this discussion do not forget thta in order to avoid hitting a harndened tool lwith a hardened hammer face yoiu can also use a softer hammer. I use a brass one for any work with a hard tool. I also use the brass when cutting over the hot cut hardy, I do not have to worry about damage with this.

[MattBower]

Good tip on the hot cut, Rich. I never thought of that!

[petek]

Thanks for the input! Half the fun is in the experimentation, but it sure is good to have input to avoid completely re-inventing the wheel!