Chisel and Punches keep breaking in half.

[NateDJ]

Do your new punches work as you hoped? What were the procedures you settled on to make / heat treat them?

[Woody]

I continue to hear the myth that A-36 is a re-melt hodge podge of scrap with no consistency. For some reason people would rather repeat this myth than to do a bit of checking. If you do a google search you will find that a-36 is actually ASTM (American Society for Testing and Materials) standard A-36 which quite specifically states the acceptable chemical analysis for this steel. See this link for chemical analysis.

ASTM-A 36 Specifications

This is the most widely used structural steel around and to think that todays batch is whatever the steel maker wanted to throw in the furnace and remelt day is absurd.

It is easy to blame our tools or the material we use for our failures, but if we want to see the root of the problem usually all we have to do is look in the mirror.

[Quenchcrack]

Woody, well said. In fact, most steel today is made from remelted scrap. It is used in automotive, oilfield, nuclear, construction and many other applications. The melted scrap can be highly refined to purity levels that far exceed the original scrap. I agree, repeating the myth does no one any good. As for A36, heat treating it is logical in small section sizes. Typically it will have .26% Carbon and enough manganese to give it some hardenability. It can be hardened to about 55 Rc in thin sections. It will temper very quickly so use 200-300F for tool applications.

[John Martin]

I just use h-13 for my hot punches and chisels. Just grind them into shape. Nothing else. I forged a chisel. Heating to non-magnetic, let it normalize, and use to to vein all of my leaves. It's a hot working chisel. When I can, I will get some s-7 for cold working chisels.

[unkle spike]

A small toaster oven works good for heat treating anything that will fit. Beats messing up the wifes oven with Oil and such...

[bigfootnampa]

Water quench is almost always too fast for HC steels anyway... use oil. the faster the quench the harder the steel... BUT overhardening excessively is poor practice as the stresses of fast quenching will warp, weaken, deform, sometimes even crack the steel. If the quench is perfect you are ready to go when the tool comes out of it! Though to acheive zone hardened steel it is often useful to overharden and temper back... just don't get carried away with the OVERhardening phase. Sounds like you really need some better steel too.

[bigfootnampa]

Water quench is almost always too fast for HC steels anyway... use oil. the faster the quench the harder the steel... BUT overhardening excessively is poor practice as the stresses of fast quenching will warp, weaken, deform, sometimes even crack the steel. If the quench is perfect you are ready to go when the tool comes out of it! Though to acheive zone hardened steel it is often useful to overharden and temper back... just don't get carried away with the OVERhardening phase. Sounds like you really need some better steel too.

BTW Thomas is right about immersing the whole tool and you should be moving it in a figure eight pattern too as it is cooling. The tool is PLUNGED (very quickly) into the quench because any hesitation at all can leave a seam of weakness in the steel. Don't take it out right away either, especially for the oil or brine quenches, cooling heavy tools takes some time... keep moving it around in the quench until it is thoroughlly cooled. For critical operations like sword hardening you need a long trough of quenchant into which the sword may be plunged edge first (rather than from tip to hilt), so you can see that this is a much more important factor than you have been allowing for.