Wednesday, May 4, 2016

Forging Specialized Blades

Khukri, Sickles, and Saws are all difficult to make for an average newbie smith. Newbies usually learn scrolls, bowie knives, nails, hinges, smithing tools, and some decorative work when just starting out. (I base this assumption on my books and experience.)
 
Khukri are actually very simple. They are forged first for a reversed distal taper, and then you forge the point like with a Seax. A Khukri's method is essentially the same as a Seax, but the degree of the initial downward sweep and the distal taper are different as is the outcome (a Seax results in a straight blade due to the opposing forces of the flat hammering and the spine hammering). Next you put the blade over the anvil so the edge is directed at the top of the anvil and the spine is facing up. Make sure about half of the blade hangs off the anvil. Strike the spine of the blade starting at the point. Use the same hammer strokes you do for scrollwork. Next you forge the edge, turn the blade so it is flat on the anvil with the edge facing you and so the area being worked is flush with the edge of the anvil's face. This was easy for me since I have a square anvil with no horn. Next you forge the sides to form the taper from spine to edge. If you've made knives of any kind before, this will be easy. I've forged single bevels (like Japanese sushi knives) and double bevels alike. Be sure to keep it all straight so the blade doesn't warp. I use a 4oz ball peen hammer for straightening blades. The deep belly of the Khukri comes from the forging of the reverse distal taper. The distal taper of the finished piece will be regular up to the belly, then taper to the point. 
 
Sickles are essentially the same procedure as the Khukri, but instead of the reverse, there is a regular distal taper. You can forge the end of the tang into a ring (scroll forge into a 9 shape, then forge a right angle in the connection point on the edge of the anvil after quenching the round to keep its shape) for a Kerambit, or forge it into a right angle for attaching to a stick to make a rice sickle. 
 
Saw Blades are another simple one. I use 15n20 spring steel for them. First cut it to size with a hacksaw. 15n20 from New Jersey Steel Baron already comes the proper width and depth for a small saw. I cut it to length, anneal it, drill holes for the handle (totally up to the smith how you want to do that), and break out the sharpie. Draw a straight line about 2-3 mm from the edge. Clamp the saw blade in a vice with the edge up. Take out the triangular chisel and start filing into the blade down to the edge of the line. I make mine to cut on the pull stroke. Compare to a crosscut saw to be sure you are doing it right. Next, heat it up to a dull red and set the teeth. You offset each tooth in the opposite direction as the ones next to it. Try to get them all evenly offset, and try to match the offset of your example saw. Next is the sharpening, anneal the blade again, go back in with your triangular file and sharpen each tooth. Then heat it to cherry red and quench just the teeth in oil, allowing the rest of the blade to cool on its own. Next you clean it. I suggest a hoppes #9 to get rid of the grease, and vinegar and steel wool to get rid of the scale. DO NOT USE A BUFFING WHEEL. It will yank the saw out of your hands and send it flying.

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