Tuesday, August 16, 2011

The 20-year home-made knife

I'm not really sure what makes 14-year-old boys want what they want and do what they do. When I was 14, I had already spent years saving money and buying knives of various sorts. I had my deer hunting knife; a smaller, lighter knife with a half-serrated blade that I preferred for pheasant; one or two Swiss army knives; a Leatherman ... and probably several others. Yet, for all my useful knives, I still wanted a boot knife. Not a big one, and I certainly don't know what for, but I wanted one ... just not badly enough to save up money to pay for it.

Through all of my knife-buying years, even when buying relative bargain knives, I have required good steel ... always. So, not just any $10 boot knife from an infomercial was going to fill the need. I wanted something that would hold an edge through abuse, and though I didn't have a boot knife, I did have a file.

Metal files are made of high-carbon steel. While not rust proof (or resistant), high-carbon steel has one very desirable attribute for knife making ... hardness. File steel is made for cutting metal, so it should come as no surprise that it is harder than most other metals. This attribute, while contributing a certain amount of brittleness, means that a blade made from the same material will hold up to a great deal of abuse, maintaining its sharpened edge through it all.

The Blade

So, the first step in making the knife was to shape the blade. Nope ... I take that back. The first step was to borrow a bench grinder from my dad's neighbor ... then start shaping the blade. I really don't know how long I ground on that blade, but over the course of several days, a relatively innocuous file turned into a rather precarious double-bladed knife, slowly thinning, shaping and shortening as it went. Then the trouble started.

When I finished shaping the blade, I found that I had not really considered what was appropriate for a handle. Unfortunately, what I lacked in ideas, I made up for by getting lots of advice. Though I won't go into the whole story of how the knife-making project fell into shadows, I must have started thinking more about girls than that knife, because execution of all the ideas thrown at me was done very poorly, resulting in several failed attempts at different handles and the lack of a decent tang on which to mount a handle. In the end, I cold-blued the blade to protect it, and it behaved as a letter opener for many years.

Moving forward 20 years, one wife, and 3 children....

The other night I found myself bored. Not without things to do, but bored. In my boredom, I started cleaning and once again found this glorified letter-opener screaming, "HA!  I beat you!" and for some reason, the game was on!

To the garage I went, grabbed my angle grinder and went to work. Still lacking a decent tang, I shortened the blade significantly to add about a 2.5-inch tang, with a rather odd shape at the bottom. Initially, I intended to make the bottom a wedge shape to hold tight in the fiberglass that would ultimately become a handle. However, after some consideration, I realized if I made the wedge a solid wedge, the slot in the hilt would not be able to fit over it from the bottom, so the final design was more of a hook shape than a wedge, and probably holds even better in the fiberglass than the wedge would have.

Through my grinding process, I also removed some light surface rust that the years had left behind and all of the very poor bluing job, planning to improve the finish at a later time. After the grinding was done, I started working on the blade with progressively finer sand papers, finishing with 1000 grit 3M micro-finishing paper.  The end result was quite nice.

Finally, On to the Hilt.  

Using a piece of scrap steel from my garage, I went to the effort of grinding a hilt. Since I wanted to keep the weight down, the hilt is not entirely steel, but steel backed by fiberglass, therefore only the part that might take abuse is steel, the rest is part of the fiberglass handle.

A Fiberglass Mold.

After about an hour of grinding the blade and hilt, it was time to make a mold for a handle. I knew when I was doing it, I should be taking pictures, though my fury to finish would not allow me to stop.

I drew one half of the rough design I wanted on a piece of paper, folded it in half lengthwise, then cut it out. The fold allowed me to cut both sides of the handle shape at the same time, providing very nice symmetry for my pattern (If only my band-saw had been as good). The paper cutout was then sprayed with a low-tac adhesive and stuck to a piece of 3/8 inch plywood, then spray painted and the paper removed. By doing this, I had a very sharp outline of the proposed handle shape to follow with my jigsaw.

When the paint was dry (10 minutes - I LOVE KRYLON!) I took the board to my jigsaw and removed the unpainted image of my handle-to-be, along with a slot for the blade out in front. I then screwed the wooden outline to a backboard and customized such that the blade and hilt would be held firmly in place while suspending the tang into the middle of the fiberglass slurry.

Glass bedding kits for rifles come with very short strands of fiberglass to mix with the resin. Unfortunately, I didn't have a bedding kit available, but I did have woven glass cloth and automotive resin. I slowly unraveled 1/2 inch squares of fiberglass cloth until I had roughly a cup of short strands in my mixing bowl. I added the resin and hardener and mixed the whole mess until I had a fibrous bowl of smelly goo, which I promptly put into my mold.

Having used nothing as a release agent, the handle was very difficult to remove from my mold and the mold ultimately had to be cut off of the knife, thus destroying any chance of an after-the fact picture.  I spent quite a bit of time finish shaping it on my home-built sanding drum, then moved progressively up to 600 grit sand paper before masking the blade and spraying it with Krylon ultra-flat paint for its final finish.

Blade Finish

Nearly complete, I returned to the matter of protecting the blade from rust.  As discussed above, the blade is high-carbon steel and NOT stainless. Therefore, there is a possibility of rust at any time if the blade is not properly cared for. One appropriate solution for this would be to re-blue the blade, another consideration was to spray it with Brownelle's Alumahyde. Ultimately, I landed on the prospect of trying something new, and I chose household chemicals in stead.

Using an acid mixture made of vinegar, lemon juice, and green Rit dye, I submerged the blade for 20 minutes. Though I don't really believe at this point that the Rit dye bought me any benefit, the resulting patina was quite nice and should provide years of rust prevention.


Shown below is the knife with a rather crude first attempt at a leather sheath.  The Sheath 2.0 is currently under construction, but has bogged down as a guy can only push a needle through three layers of leather for so long before boredom overtakes him.  But hey, there's no hurry!  Maybe I'll finish in another 20 years!

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