Temper Metal..need to know?
Question:Hey folks, I need to know how to get a good solid temper on steel digging bars. We do some heavy duty digging and they need to be sharpened often and many times they break. To sharpen we use a bench grinder, I know it would be better to heat the metal and pound out a point but that takes to long.
I have heard to dip it in oil or stick it in the ground after it is heated from the grinding. Whats your opinion?
Answers:
If you can get it hot enough to get a blue to orange transition color it should case harden the tip. Whats happening to cause breaking is work hardening. A good digging bar is made of mild steel with only the tip tempered, this helps relieve the ringing in your hands if the entire bar is tempered, as is the case of bars made from from old axles.
You will not heat the metal enough through grinding to make it temper through quenching.
Of the two I would use oil if the edge is not too hot. Do you have a gas torch you could heat the edge with that after grinding and then cool in water it the temper color you thing works best blue, brown, red, or what very. I have trouble keeping the color change in my head just know them when I see them. This would put the temp in the edge of the piece.
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