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I Forge Iron

First blacksmith's knife


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Made a small utility knife for the shop out of coil spring. 


This was my first blacksmith’s knife – only my third finished knife, and the most forged-to-finish of any of them. I’m not particularly happy with the shape of the blade. I should have tapered the round stock a lot more before flattening it, as that would have been a lot easier than trying to draw out the profile taper afterwards. The bevels were asymmetrical and needed a lot of corrective grinding. Distal taper is acceptable. I hadn’t drawn out quite as much stock for the handle as I should have, and it ended up shorter than expected. Still, it does fit my hand pretty well.

I’m burning rice coal (anthracite) in the forge, so getting an even heat on the blade before hardening was actually a lot of fun: the small pieces of coal act almost like a liquid, and you can stir the blade around in it, pile it around the blade, and so on, to get things just right. I did a water quench (not having any oil) after one normalization, and while it worked well, I knew it was a gamble that I would not take with a longer blade. Tested with a file, and it skated like an Olympian. Tempered the blade on a railroad spike heated to yellow, which initially didn’t work very well: the temperature in my garage was about 30°F, and it was cooling off too quickly. So, I heated up two spikes and alternated them until I’d gotten the blade to a dark straw on the edge and blue on the spine. Never done a graduated temper on a knife before, and it was a lot of fun watching the colors inch across the blade. Very happy with how much control the hot spikes gave for applying the tempering heat.

Ground the bevels out with my 4-1/2” angle grinder, cooling frequently in water. (Note to self: wet fingers + cold air = unpleasant.) Tricky getting the profile right without overheating the steel, and I didn’t bother to completely correct the asymmetry of the bevels. If this were anything other than a shop knife, I probably would have, but it’s good enough for the purpose and a reminder to do better next time. Finished shaping on a coarse bench stone and sharpened up with a medium waterstone.

All in all, a fantastic learning experience. My skills are a little bit better than they were before, I’ve got some lessons to keep in mind for the next blade, and I ended up with a nice little shop knife.

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Looks pretty nice. I like the handle, it looks like it wouod fit the hand well. You seem to have drawn the metal out very nicely, for the amount you had to work with. I realize it's just a shop knife, but why not take your grinder and sandpaper and clean up the flat section between the bevel and the spine? For what it's worth too, I find it useful to forge the blade out, and clean it all up, grind your bevels to finish, get it where you want it, then quench it in a separate fire. That way you don't need to worry about ruining the hardness with the grinding. And I usually forge out another knife, or whatever you have to make, in the same fire I used to quench the blade, so your not wasting the fuel just for a quench. That's just my process though. Looks like that blade will serve you well though. 

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A heat treating trick is to stick the closed end a piece of pipe into your fire and let it get hot, rotating it until it's a nice even heat and sticking your blade in that to heat up while you hold it---I go spine down as it's usually hotter on the bottom.  Put some crushed chunk charcoal , (NOT Briquettes!), in the bottom of the pipe when you start heating it to make a reducing atmosphere for less/no scale.

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