Blacksmithing
and Cutlery
by Gérard HEUTTE
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Manual case hardening
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This page describes the simplest way to make case hardening. No special equipment is
required.
Thank you to the young reporter, my daughter Lorène, for the pictures...
Principle
Nothing more simple. The blade is heated to the right temperature, then put
the edge (only) in the goop. The immersed part will cool quickly and thus will be quenched.
The emerged part will cool more slowly and will not be quenched!
The main disadvantage of this technique is that the temper line is necessarily straight.
It is possible to partially solve this point by quenching the blade in a reduced height of oil
(e.g. 1cm). By pressing the blade against the bottom of the can (or a wedge if it is too deep),
it is possible to have a temper line parallel to the edge.
Preparation
Here is the blade that will be used. The picture shows the blade fixed on a special handle.
As I make much Piedmontese, I have built this tool to handle the blades easily.
Just use a flat part, drilled and cut out to leave space for the pallet.
Heating
Heating is made in a usual way. You can use a magnet to find the right temperature. The blade will
be heated by the edge. Be specialy careful to not overheat the edge.
As the back of the blade will not be quenced, its temperature is not important.
Heating the blade.
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Test with a magnet.
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Quenching
For quenching, remove the blade from the fire and put it in the goop on the required depth.
Take care to quench the tip on a sufficient distance (1 cm behind) and all the edge.
Wait the total cooling of the blade to remove it from the goop.
Progressive cooling of the blade...
The blade just after quenching.
Result
Here is the result of this technique with a suitable steel gives (C70 / 1070) on finished
blades:
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