Hand Tools Archive

Subject:
Re: A great and helpful summary...

Rum
I think in general sharp edges invite cracking. Whether that be at the future cutting edge or along the other sides.. so some mild rounding on all edges before quenching and then refining to a crisp edge after tempering seems smart imho.

Interestingly this is the same behavior when making things from green wood and drying them - sharp edges == more cracks, and ditto overly fast or uneven drying (aka shrinkage which is more or less the same issue as an overly fast quench). It seems the more you learn the more its all related.

My (again wholly unsupported by direct facts) belief is that the interrupted water quench mostly evolved mostly due to a lack of reasonable tempering equipment that could hold temperature accurately for a long enough time. It's certainly a higher skill technique and more prone to error. I think also the differential hardening can be beneficial for some tools but its not an extremely compelling feature for 99% of the things.

Alignment when quencing also can make a big difference in the success rate regards warping and cracking. Generally even to heat, even to cool gives the best results (within the constraints of the equipment). My dad was of the "alignment with the magnetic field" matters camp as well (at least for knife blades plunged vertically facing north/south), I think there's something to that because the reforming crystals will pick up some magnetic alignment, but I'm unsure how much difference it makes in practice. I'm also unsure how that would translate to most of the tools we're talking about here.

On literature, somewhat dated, but still pretty interesting from a backyard blacksmith perspective is "Hardening, tempering, annealing and forging of steel ; A treatise on the practical treatment and working of high and low grade steel" by Joseph Vincent Woodworth. I also have a copy of "forging" by John Jernberg which is similarily useful. Both have at least a couple of copies on archive.org as they are long out of copyright (I have an inordinate fondness for dead trees but its often useful to read things before commiting the shelf space when possible). I can't say they're more directly accurate than the various modern internet sources but tend to have a somewhat broader and less bladesmith specific perspective.

Learning some forging is imho useful as its a lower effort than bulk removal of material and I kind of like some of the aesthetics :) But I'm currently living with similar capability restrictions so you have my sympathies there. I'd like to move to someplace where I could setup a decent smithing shop again one of these days but it's not in the immediate cards. Ah well we work with what we have.

On 99% of things like files I'm mostly into buying old stock or deals on new-old-stock when I can find them. I'm pretty sure I've seen a vixen or two in some of the hot-rod head estate sales around so will be keeping my eye open. The newer stuff is often rather dodgy hardness as well (point of course belabored to death everywhere already). If I only used tools for their intended purpose that would loose me about 1/2 of what I do 8) For example I had to do a small amount of sheet metal work for a friends project the other day but don't have a decent pair of duck bill sheet metal pliers but an upholstery webbing stretcher worked pretty nicely (and making a small redneck brake of sorts out of four old power planer blades plus a couple of vise grips worked a trick as well).

Another technique that is extremely useful but hated pretty universally by everyone who uses it because of the hot metal shards is hot rasping. I don't recall seeing a lot of discussion of it in the literature but it's pretty commonly done by farriers shaping horseshoes (where I learned it) and can remove a hell of a lot of metal in a hurry. The nice thing about it is that you really only want to use files and rasps that are pretty much shot already as sharp ones are way to grabby, so those old files that Bogs marked with red as "never to sharpen again" can have a bit of a life extension for this (before getting recycled into something else). I think for your purposes it would likely be a really good trick to have though. I won't go into the details much more as there are various youtube videos now that show it better than I can explain it.

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