First, I use my template to draw the shape of the blade onto a piece of O1 tool steel flat bar. I use a template for this because the spacing between the pivot hole and the "stop points" for the open and closed positions have to be pretty acurate. This way I don't have to measure it from scratch every time.
Then, I begin to saw away chunks of steel, using my trusty hacksaw, until I get a very rough outline of the blade cut out. At this point I also drill the pivot hole using the drill-press.
Next, I refine the profile of the blade using hand files until I get pretty close to what I want.
Before I do any more work on the blade I make the brass liners. I do this now because I want to to have wooden scales on the sides of the knife. These need to be glued onto the brass liners and the epoxy glue I use takes at least 18 hours to cure. So I like to get them glueing as soon as possible so that I can do some more work on the blade while that's happening. I shape the liners the same way as I shaped the blade. As I'm doing this, I also make some small adjustments to the stop points on the blade so that everything fits up nicely.
Next, I prepare the wood to be glued to the brass liners. Here I'm using walnut. First I mark the piece to be cut out from the board and then cut it.
...Not the straightest cut I've ever done :oP
Then I cut the piece I just cut out in half. This will give me two pieces, one for each liner.
That's more like it. Nice and straight...ish :o)
Final step before glueing is to rough up the sides that will be glued with some 60 gritt sandpaper. I do this because epoxy glue bonds better to rough surfaces.
Then I just apply the epoxy glue and clamp the pieces together. As mentioned above, the glue I'm using requires at least 18 hours to cure. So I leave that sit until the next day.
Now I can get back to working on the blade. I scribe a center line where the edge is going to be, and mark where the plunge line will be also. The center line will act as a guide to help me keep the edge straight and centered.
Then I use an angle grinder to grind a very rough bevel onto each side of the blade. I'm not trying to be exact here at all. I'm simply removing some metal with the grinder so that I don't have to file it all away by hand.
Once I've hit both sides with the angle grinder, I file in the plunge line and start to roughly file both sides flat.
Then I draw-file both sides until they are properly flat. Draw filing is a technique where you place the file on the blade and push accross the area to be filed, in this case the bevel of the blade from tip to plunge line. If the angle of the file is kept consistent a nice flat surface can be achieved.
Then I sand the bevels by hand with 60 gritt, 100 gritt and finally 150 gritt sandpaper.
The final thing to be done to the blade before heat treating is to do the filework along the spine. I do this with my trusty set of needle files.
Picture didn't come out too great. But you can see the file work on the finished knife clearly.
Next I continue work on the handle. First I roughly rasp the wood to the same profile as the liners.
Then I rasp it down to about 3/4mm thick. I do this until I get both sides about as close to the same as I can get them. At this point I also drill the pin holes through the wood.
Then I make the back spacer out of a scrap piece of O1 tool steel that has the same thickness as the blade. I shape this by hand in the same way that I shaped the blade and liners.
Some simple file work.
Once that's done, I start sanding all the handle pieces by hand. I sand the inside of the liners to 400 grit, and the outside wood to 150 grit. Once the knife is put together I will sand it down nicely to a higher grit. I also countersink the pin holes at this point.
Now it's time to heat treat the blade. The first step of heat treating is normalising the steel. This is done by heating the blade until it becomes non-magnetic, then letting it cool in the air to room temperature. This is done three times. The purpose of normalising is to relieve any stresses in the steel, which may cause problems during hardening or later on during use, and to even out the structure of the steel.
Had to take this without flash in order to see the steel glowing, so unfortunately the picture quality is pretty bad.
The next step is to harden the blade. This is done by once again heating the blade until it becomes non-magnetic and then quenching it in oil. The rapid cooling process will result in a very hard blade.
At this point the blade is very hard and brittle...so essentially it's useless as a knife. That's why we temper the hardened steel. Tempering is done by heating the steel to a certain degree in order relieve stress from hardening, and to toughen the steel so that it becomes less brittle but still hard enough to hold an edge. I differential temper all my blades using a small blowtorch. This means that differnt degrees of tempering can be achieved on different portions of the blade. In this case, I give the pivot area a full temper (for toughness), the cutting bevel is tempered to a light straw colour (for hardness and edge retention), the spine is tempered to a dark blue/purple colour (this makes the blade more flexible and tougher than if it was tempered entirely to a straw colour), and the very tip is tempered to a brown/purple colour (here I'm sacrificing a bit of edge retention for some extra toughness. I do this on the tip so that it does not snap off as easily). I temper my blades three times.
Next I sand the cutting bevel by hand all the way to a 1200 grit finish. I don't sand the rest of the blade too much because I want it to look rough. I want the knife to have a slightly aged/antique look to it in the end.
...Very important for moral :o)
The last thing I do before assembling the knife is to put my maker's mark on the blade. My maker's mark consists of the two runes for F and W (my initials) from the Elder Futhark, which stand for "luck" and "joy". The Elder Futhark was the runic alphabet used by Germanic tribes during the 2nd-8th centuries AD. I do this using a process called electronic etching. The first thing I do is make the stencil for the mark. I do this by sticking some insulating tape on the blade and then cutting out the two runes.
Then, using a 9 volt battery and some salt water, I etch the mark into the blade. In the picture below you can see the positive lead from the battery is connected to the blade. The negative lead has a piece of cotton cloth taped to it. This is soaked in salt water and pressed onto the stencil. When the electical current flows through the salt water it causes the steel that it's touching to corrode rapidly. The insulating tape protects the rest of the blade, so only the bits that I cut away get etched.
Now I assemble the knife. I put all the pieces together and rivet the ends of the brass pins to hold them all in place. Next I moisten the wood to make the fibers stand up and then sand it smooth using some 320 grit paper. Once that's done I treat it with boiled linsead oil.
Now all that's left to do is to sharpen that bad boy. I do this first on a 1000 grit waterstone, then a 6000 grit waterstone and finally I strop it on a leather strop.
And that's it.
Click here to see larger versions of the pictures of the finished knife.