spine tempering

Keith_H

Keith_H

Joined
Jul 20, 2007
Messages
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I thought that i would start a thread to commemorate my new gold membership. :D

I got into thinking that a springy spine would be better then a soft spine, but i know that a proper temper cannot be done with a torch. Has anybody tried using something like two electrically heated plates along the spine to temper till springy? thanks!
 
I'll tell you what, I just passed my JS performance test, which is done with a 10 inch blade.
Using methods I have gleaned from both Ed Fowler and Kevin Cashen, and utilizing post forging quenches and my oven for sub-critical spherodizing annealing prior to quenching, I edge quenched my 5160 test blades(s). One to ensure method, and test at home, and one for actual testing with Don Hanson.
I could bend neither one by hand past, maybe, 20 degrees, which is almmost nothing.
To get to 90 degrees, I had to use a 4 foot cheater bar, and both blades returned to under 20 degrees from straight!
Now, that's NOT soft!
That is amazingly tough and springy.
The two toughest and most indestructable blades I have made in 10 years. They both defied abuse and required nothing more than what we talk about here everyday.
 
If I am going to quench the entire blade and then relieve the stress along the spine, beyond what the tempering process will give; I submerge the blade in my quench tank with the spine and tang above the water line and heat with a propane torch. If you put a subdued light on the area to be heated, it is fairly easy to get a proper springy spine by just watching the colors. The blade below the water will stay cool so as not to disturb the hardened area.
I do most of my damascus blades this way, to avoid the fuzzy looking line produced by using clay or edge quenching. Not better, just what you are looking to produce.

There are many ways to skin this cat, Fred:D
 
I would not sweat the inaccuracy of the drawing a temper with the torch as long as it is only on the spine, and never the very edge since you are correct that a blade with spine drawn back will indeed out-perform one with dead soft spine in most aspects. Martensite drawn at high temperatures with equivalent Rockwells will be both stronger and tougher than pearlitic spines, so if you get the spine much hotter than you expected with the torch, it will still outshine one that was never hardened at all. Just keep that torch off the edge, where the accuracy really counts.
 
Thanks Kevin. I will have to try some sort of toaster element press thing for long blades.
 
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