Reducing Drill Bit Wear The Cryogenic Way

There are a lot of ways that metals can be formed into various shapes. Forging, casting, and cutting are some methods of getting the metal in the correct shape. An oft-overlooked aspect of smithing (at least by non-smiths) is the effect of temperature on the final characteristics of the metal, such as strength, brittleness, and even color. A smith may dunk a freshly forged sword into a bucket of oil or water to make the metal harder, or a craftsman with a drill bit might treat it with an extremely cold temperature to keep it from wearing out as quickly.

Welcome to the world of cryogenic treatment. Unlike quenching, where a hot metal is quickly cooled to create a hard crystal structure in the metal, cryogenic treatment is done by cooling the metal off slowly, and then raising it back up to room temperature slowly as well. The two processes are related in that they both achieve a certain amount of crystal structure formation, but the extreme cold helps create even more of the structure than simply tempering and quenching it does. The crystal structure wears out much less quickly than untreated steel, therefore the bits last much longer.

[Applied Science] goes deep into the theory behind these temperature treatments on the steel, and the results speak for themselves. With the liquid nitrogen treatments the bits were easily able to drill double the number of holes on average. The experiment was single-blind too, so the subjectivity of the experimenter was limited. There’s plenty to learn about heat-treated metals as well, even if you don’t have a liquid nitrogen generator at home.

Thanks to [baldpower] for the tip!

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Blacksmith’s Junkyard Power Hammer Packs A Punch

Any way you look at it, blacksmithing is a punishing trade. Heavy tools, a red-hot forge, flying sparks, and searing metal all exact a toll on the smith’s body unless precautions are taken. After proper safety equipment and good training, a blacksmith may want to invest is power hammer to replace at least some of the heavy hammer work needed to shape hot metal.

Power hammers aren’t cheap, though, which is why [70kirkster] built one from an old engine block. You’ve got to admire the junkyard feel of this thing; it’s almost nothing but scrap. The engine block is a straight-6 from an old Ford pickup stripped of everything but the crankshaft and one piston. An electric motor spins the crankshaft and moves the hammer against the anvil through connecting rods and a trip arm fashioned from a trailer leaf spring. Everything looks super solid and the hammer hits hard; the videos below tell the tale of the build and show the hammer in action. Not bad for $100 out-of-pocket.

Blacksmithing is one of those dark arts that really deserves to have more adherents. The barriers to entry can be high, but the rewards are great. Looking to get started on the cheap? Then check out [Bil Herd]’s guide to hacking together a backyard smithy.

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