Now that the blade is completely finished it is now time for me to fit a guard and start building the handle. The fittings on this knife will be made from steel that is from the same billet as the blade.
First I have to file the shoulders on the blade perfectly square. Most people do this while the blade is soft before heat treat. Like Tim Hancock I do not. I want shoulders that are fresh and crisp. If you do it before heat treat you will round those off ever so slightly while you are hand finishing, buffing, and etching the blade. In order to file these though you must heat the area of the tang and shoulders to bring the temper down. This way they can be filed. You must be careful to not let the heat travel out into the blade and cutting edge.
I then use post-it notes to protect the blade from scratching during filing. The great thing about post-its compared to tape is that they will not compress or deform in clamping thus that giving you square shoulders.
Here I have clamped on a filing jig that will assure me a square cut. I went through three sets before I found one that would file accurately. They are a pain to open but there is NO play in them. They have a hardened face so the file will not touch them.
Squared up.
Then I surface ground a piece of Damascus to .187 which is the same thickness of the blade. Once this was surface ground I scribed a center line and then drilled some holes in the guard. I am going to mill the slot with my milling machine but the drilled holes just make the milling go easier. I am no machinist and plan on learning more as I can.
Now I clamp the guard up in my mill and cut the slot.
This is where the surface grinding comes into play from early on in the process. Remember when I said that if I plan on a .187 blade I will surface grind to around .200-.210. The reason for this is that as I work on that blade such as sanding and etching it I look a little bit of thickness. Maybe .010. So now that blade is .190-.200. The guard that I want to make has to be very tight. If I am to use a .187 milling bit that will make the guard hole undersize by about .010. In this case I can now drive my guard down into place. After driving the guard on and off about three times it will actually form to the shape of the blade leaving a perfect fit. I always plan my blade thickness and guard early so I can mill my guards using a specific diameter mill bit. This way I don't have to file my guards.
Some of this is hard to explain but I will try. The other thing I do, as does Tim, is I always mill my guards leaving shoulder inside. So if the face of the guard has a slot that is .187 then the hole in the back will be .207. This will leave .010 on each side of the blade. This shoulder is usually about .040 thick. That way when you are driving the guard down you are only asking .040 to form to the blade, not all .187.
This next picture will show you the shoulder inside.
Back of the guard, handle side, and you can see the shoulder down inside.
Face of guard.
Ready to drive. I always taper my tang ever so slightly from the shoulders on back. This allows you to slide the guard up close with out needing the drive the entire length.
