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How do you temper a chisel?

How to temper a chisel

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A broken cold chisel Because the chisel is still somewhat brittle, it must be reheated and allowed to cool again in order to make it stronger (tougher) and to ensure that the cutting edge does not break immediately after use.

Tempering does decrease the chisel’s hardness somewhat, as it is impossible to have a 100% hard and 100% tough piece of steel.

Emery paper Before you begin the reheating process, you must clean the chisel and shine it with emery paper, as the surface of the steel will change colour as it is heated, allowing you to roughly gauge the temperature.


Step 1 – Heating steel

Heat the steel. Colours will appear on the steel as it heats up. The colour you are looking for is a blue-purple.

Tool steel tempering chart, springs, screwdrivers, cutters, different types of saw, needles, chisels and cold chisels However, this may vary slightly depending on what material the chisel is to be used on.
Once this colour has been reached, the steel should be left in the open air, placed in sand or re-quenched in oil to cool it down, depending on the hardness desired.
Wonkee Donkee says, "You can quench the chisel tip at this stage. This will result in a harder, but ultimately more easily broken cutting edge."
Knife cutting sodium, a soft metal The process of heat-treating ensures that the cold chisel becomes harder than the metals it can work on.

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