Translations:Adventist Youth Honors Answer Book/Recreation/Camping Skills III/21/en
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Hatchet
It is tempting to take a dull hatchet to a power grinder, but unless you are very careful, this could be a huge mistake. A grinder will not only remove steel from a blade, it will also heat it. It is very easy to heat it too much, causing the steel to lose its temper (tempered steel is hard and holds an edge better than untempered steel). Steel is tempered by heating it to the point that it becomes non-magnetic, then quickly cooling it. If it is allowed to cool slowly, the iron crystals in the blade will align themselves with the Earth's magnetic field as they cool, and aligned crystals make for soft steel. So the first advice we can give on sharpening a hatchet is to stay away from the grinder.