James Stanley

I made a knife out of a file

Sun 28 June 2015

Since making a little knife out of a hacksaw blade a few weeks ago, I've been working on a bigger knife made from a file.

I drew the outline of the knife on to the file, and ground it out. I was careful not to let the file get too hot as this can apparently ruin the hardening of the steel and keep it from holding an edge properly. I just kept a glass of water by the grinder to dip the steel in every few seconds.

The knife has what I believe is termed a "hollow grind". I cut a block of wood at an angle and clamped the steel to it. I them dragged the steel across the grinding wheel using the wood to keep it square, hence forming a hollow grind.

At this point the surface of the file was still a file, which is not at all helpful for a knife (perhaps a knife+file multitool? but that's another project). I used the belt sander attachment on my grinder to take the teeth off the file. I actually stopped a little short of completely removing the shape of the teeth as I like the look of it.

I used some more of the oak offcuts I have to make the handle. I tried to drill some holes through the tang to use pins to hold the handle on, but the steel is unfortunately too hard! I expected to have trouble drilling the holes but had no idea it would be this hard. I even heated the tang up to the point where it changed colour in an effort to ruin the hardening (who needs a hardened handle?) but to no avail. The only outcome of my efforts toward drilling holes was a blunted drill bit.

No matter, I simply epoxied the oak to the tang with no pins. Once the epoxy had dried, I shaped it on the belt sander. I removed the "table" from the belt sander so that the belt could flex a bit to help make the rounded edges. This worked better than expected.

Next I polished the blade a bit using a polishing wheel on my Dremel (but it could have done with a bit more polishing). I tried to sharpen the blade but I am still rubbish at it. The knife is sharp enough to get by but I wish I was able to sharpen knives better...

Finally I applied wax to the handle.

The main mistake with this knife is that the point of the blade is not quite a point due to the wooden blocks method I used to grind it. Ideally I would have kept the tangent of the edge of the blade parallel to the ground at the point of grinding, but I just kept the body of the blade parallel to the ground.

I'm pretty pleased with the result. More pictures here. I didn't take as many as I ought to have done.