A saya nomi is a Japanese-style chisel for making scabbards.
The basic shape is a curved chisel that can be pushed into the wood then pressed down to lever a little piece out. The outline of where the cut will be is traced with a utility knife, a kiridashi, Japanese scabbards (saya) are very precisely fit, the kiridashi and saya nomi are used with painstaking care to cut the wood so that the only contact-point with the blade is along its spine.
I know I’m going to need one eventually, and I just made a nice bar of twisted medium layer 1095 and 15N20 – why not make one? I’ll put the pretty twist stuff on the top and the serious no-nonsense 1095 on the bottom and it’ll be really pretty with a two-tone look. It’ll be good practice with my hammer; shaping long tangs is a fun process. What you do is heat it, then use the rounding-face of your hammer to hit one side, turn it 90 degrees, hit the other, turn it, etc. The rounded face of the hammer drives the metal away from it, which means it stays rectangular but gets longer.
So I cut the bars and tack welded them together, then forged them into a rough chisel-shape. The Japanese saya nomi don’t have a tang through the entire handle, to keep an impatient scabbard-maker from tapping on the end with a little hammer, but mine will:
From there, it’s going to be a matter of cleaning the forge scale off, rough-shaping it, then quenching it and fine shaping it, making a handle and end cap, drilling it, threading the cap and peening it over. Piece of cake! By now you can walk through the steps in your sleep, too, right?
At this point it’s still soft(ish) metal; I can bend it in a vise or whatever. I will tweak it a bit more and next time I have the forge hot I’ll quench it. Before I do that, I’ll bend the chisel part to where I want it, and I’ll straighten the tang straight enough to make a machinist happy. OK, you can’t actually hand-shape anything that accurately, but maybe a machinist won’t wince visibly.
I think that looks pretty spiffy!
I want to see how spiffy it will be, so I decide to do a test etch. There’s no harm in that; all that metal will get ground off anyway. So I latch a magnet onto the tang and drop it into my Etch Tanks 2.0. Etch Tanks 1.0 were 4 feet tall and bolted to the floor; these are much more practical. Also, Etch Tanks 1.0 had a thin PVC ballast plug at the bottom, which turned out the bad the first time I dropped a blade 4 feet point-first onto the ballast plug and 2 gallons of ferric chloride dripped overnight onto the shop floor.
When that is done. I neutralize it with soda/water (right tank) and…
No. No way that happened.Somewhen in the process of drawing out the tang I lost track of the rotational angle. The pretty twist damascus is not on the top where it’s supposed to be, it’s on the right hand side.
It’d still make a perfectly fine chisel except, instead of having a chisel where everyone will look at it and go, “that is a fine chisel” they’ll go “why did he do it that way?” and – more important – I will want to /facepalm, which is a bad thing to do when you are holding a chisel!
This is really awkward. I love fine tools and my plan was to make myself something I would enjoy using not something that will torture my aesthetics every time I look at it. I could put it on the Shelf of Shame and Woe. I could destructively test it (I already know it’s strong as steel). I could grind the tip into a point and put bevels on it and a handle and call it a “tactical samurai peanut butter spreader.” I could heat it and squash it from the other edge, which would almost certainly mess it up.
Unfortunately I have really got to stop messing around and get the doors and power set up in the hot metal shed. It’s getting cold and damp and I have to get some infrastructure work done instead of just messing with fun little projects. I’ve also got a couple of commissions I have to build, I need to make Death To Christmas(tm) holiday caramel corn, and more other things than I want to count. So the saya nomi issue will just have to wait.
I’m happy I can make mistakes like this at all, but it stings right now.
The weekend of the 14th I will probably fall silent. My buddy Mike G, who is an amazing woodworker, is coming up to teach me some things and to show me what’s wrong with my design for the shop doors. Mike works wood as expertly and enthusiastically as I eat pizza. We’re going to try to get the doors onto the shop. In the meantime I’ll be doing a bit less blogging and a bit more electrical work.