Learning Something New - Part 2
This is the second post in a two part series on my process creating my first knife. For part one please click here.
At this point I had my blade all ready for the all important heat treat. Just one problem... I didn't have a source of heat available that would get hot enough. Heat treating is the most critical aspect of knife making. This takes a knife-shaped bit of steel and turns it into an actual edge tool. See, in order to be able to use the files and everything to get our steel into shape it needs to be relatively soft. Soft does not make a knife, though. Sure, you can put an edge on it, sharpen it down to a razor's edge, and it will cut ... a couple times until it becomes dull. No, you need to heat treat the blade to cause a chemical change in the steel, making it hard and able to hold that edge.
Each type of steel has a different method of heat treating, but for the 1095 steel I was using you need to get it up to about 1500 degrees before you quench in oil. You can use a torch, but you need something like oxy acetylene just the standard propane bernzomatic isn't going to cut it. As mentioned before you can do this with coal, but you need some forced air to make it burn hot though so even though I have a wood stove in the house that wasn't going to get hot enough either. In the end I ended up going a little crazy and buying a high end forge from Majestic Forge. If you've ever seen the show Forged in Fire or the episode of the Mythbusters episode "Cooking Chaos" with the custom made giant forge for their shrimp canon these are the guys that built those forges.
While waiting for the forge (which actually shipped and arrived very quickly) I started work on the handle scales. When we bought the house the previous owner was a hobbiest wood worker and had left some scrap wood. In the UP one of the exotic woods we have pretty ready access to is bird's eye maple and there were a couple pieces of that in with the scrap. I got a piece a little bigger than I needed then split it down the side. I used the sander to get the pieces perfectly flat on one side so they would mate with the tang properly.
I cut a two pieces of my brass stock for the pins and then I drilled out the holes. You take the tang and lay it across one scale and then drill your first hole through the existing hold in the tang. Then you put one of those pins in as a "locator" pin. This will make sure when you drill the second hole everything lines up perfectly. For the other scale you flip everything over and drill through the first scale/tang into the other scale, then use your locator pin and drill the last hole. This all this is to make sure you have a perfect fit when everything is done.
You want to leave your scales pretty rough around the edges if you're doing a full tang handle (as I was). However, you need to perfectly finish one part, and that's the front up by the ricasso. Take both scales and put them together without the blade in, using both pins, and completely contour and finish this edge. I went up to 1000 grit sand paper, but I probably could have stopped at 600.
Once the forge arrived it was time for that heat treat. One tip I got from watching Walter's videos is that steel will lose its magnetic properties a little before that 1500 degree mark so I took my blade out to the forge with my peanut oil for quenching and a magnet. I held the knife by the tang with wolf jaw tongs and heated it up in my forge, testing with the magnet until it wouldn't stick then heated it up just a little longer before plunging it into the oil. How do you know if you did it right? It's actually pretty easy: grab a file and go over the edge. If it "bites" into the metal it's still to soft and didn't properly harden. If it just kind of skates across then you know you have a hard edge.
I pulled out my file and gave it a go and it worked! Mostly ... There was still a spot down by the tang that was on the soft side. Back into the forge it went and I attempted to get a more even heat over the edge. After my second quench things were good. After your blade is quenched it's hard, potentially too hard, which is why part of the heat treat regimen calls for tempering after the quench. Again all steels are a little different, but with 1095 you want to go for two one hour sessions around 400-475. You don't need a special heat treat oven for this. A regular oven works fine, or a toaster oven, in my case.
Getting the home stretch now! Our blade is an actual blade, but it's pretty dirty. You get a bunch of "Scale" on your blade form the quench process so you want to clean that up and sand your blade up to your desired finish. If you're going for a matte finish you can stop around 320, maybe a little higher if you want. If you want that mirror shine you'll want to go much higher. I went for matte, and not just because it's much faster - why would you even suggest that?
After your blade is finished to the desired amount you need to clean/degrease it. I used regular old lacquer thinner and then I took scorch brite medium metal pads (the purpleish ones) and scuffed up the tang. You want a clean, but rough surface for the epoxy to bond to. Once it's scuffed up, wipe with plain paper towel.
There's a ton of epoxy options out there. Walter has a two part video series just on epoxy. I ended up going with a common 60 minute epoxy I got off Amazon. First, I made sure everything was lining up and fitting properly. There was a little stick with one of the pins that took a little force, so I made sure I had my hammer to tap it in. I mixed the epoxy on some painter's tape and slathered one scale and placed the tang on it then rolled the pins in the epoxy and pushed them into the holes, finally slathered the other scale and fit everything together. With 60 minute epoxy you have a little more time to make sure everything's going right. Once it was all in place I got the clamps out and clamped everything up and then cleaned off the squeeze out with paper towel. Then it's time to wait.
Twenty-four hours later it was time to finish this thing! I took the clamps off and trimmed the pins down to the wood and started to sand. I purposely left the top of the scales perfectly flat and only contoured the bottom of the grip. Once I was finally done sanding I used a bee's wax and mineral oil blend that I use on my kitchen tools. As I was intending this to be a paring knife I wanted to make sure to use something food safe. The last step is to run it over the sharpening stone a few times to get the final bit of sharpness.
So that's the story of my first blade. My scales aren't quite symmetrical, I don't have a defined plunge line, and the finish of the blade isn't great. There were a few gouges that just would have taken too long to clean up the way I was doing it, but it is a knife! It's also not a very good paring knife, as it turned out. It's a bit too fat and the bevel doesn't taper perfectly so it doesn't cut food all that well. Oh well, on to the next one!