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Making A Knife

June 15, 2007

With only a few hours and a little bit of effort, nearly anyone can make a knife that is not only useful, but looks good, too.  Here’s how to do it.

Finding a blade
The first thing you need to know is that all steel is not created equal. When making a knife, you want steel that will hold an edge but is not too hard to grind into shape. Large round saw blades, the kind used in sawmills, often about five feet in diameter, work very well, as do lawn mower blades, old chainsaw bars, and larger files. In almost any old horse barn or tool shed, or even in your grandfather’s basement, you can usually find a large, rusty old file known as a wood rasp. Farriers use them to shape horses’ hooves. I got mine about 3 months ago from an antique tool trader who had about a dozen of them in a bucket for $1 each. I picked out the largest one. It was about 16” long and 3/8” thick at the thickest part.

Since I don’t have a plasma cutter or any other way to cut steel, I took the file to a welding shop down the road to get the rough cutting done.
First, draw an outline on the file with a permanent marker in the shape you want the knife to be,  then cut it out using a torch or plasma cutter. Once this is done, heat the entire file to a dull red color, and then allow it to cool slowly in the air. (Files are so hard that they need some of the temper removed in order for the steel to be ground down.)

Next, secure it in a table vise, and shape it with a hand-held grinder. Grinding and shaping the blade to your personal taste and design is the most rewarding, and also the most time-consuming. I spent about 45 minutes with the disc grinder forming the knife into its proper shape.

NOTE: Be sure to move up and down the knife quickly while grinding, frequently dipping it in water, so that you never burn the steel or turn it blue in one area, which will damage the temper. Never grind or sand unless you are wearing safety goggles or glasses. If you are going to do much metal grinding, you will need to wear a dust mask.

Next, switch to a sander with 80 grit sand paper. If you do not have a bench-top sander, you can always use an 8” or 4” grinder or even a small hand-held belt sander.  Smooth the surface of the entire blade and handle, switching from the 80 grit paper to 120, then to a 320 grit sand paper, getting all the little marks out, or until you are satisfied. Remember, the higher the number of grit, the smoother the paper and the smoother the finish.

Then, take a 5/32” drill bit, and drill a hole in the center of the handle about 1/4” from the end. Next take a 3/8” bit to round the 5/32” hole edges.

Treating the blade
To give the blade a different look and to make it more rust resistant, I decided to acid etch it. There are many different finishes you can do that work well and look good.  Just to name a few, titanium oxide, cold blueing, and paint, all work well as finishes. Or, you could just leave it bare, and wipe off any moisture. Occasionally, polish it with very fine sandpaper (400–600 grit) to maintain the bright metal finish.

I had a gallon of muriatic acid (hydrochloric acid) left over from a concrete job I did a few months ago, so I decided to use this for my acid-etched finish. This acid is available at local hardware stores and pool supply stores. As with all acids, BE CAREFUL! Always follow manufacturer’s instructions, and always stay upwind; the fumes are nasty. It is terribly dangerous. So be especially careful around anything that you want to stay alive, including kids, pets, and plants.
I took a 16” length section of a 3” PVC pipe and glued a cap on one end. Next, I poured about 12” of acid into the pipe, which took nearly a gallon. Then I put a piece of wire through the hole at the end of the file, to dip it in the acid, where I left it for about 1 minute. I then removed the knife and carefully sprayed it off with a garden hose, being careful to maintain my distance and not get into the splash zone.

Handle material
There are a number of materials good for handles on hunting knives, and I like them all. But for the sake of convenience, availability, and practicality, it’s hard to beat parachute cord.

Use a 9-foot length of parachute cord, and heat the end over fire (I heated mine over my gas stove) until it is melting hot. Then with a paper towel, smooth it off to a point. This keeps it from fraying.

Next, place the cord in warm water for 5 minutes. This makes it stretch. With a small screwdriver, push one end of the cord through the hole in the handle until you have about a foot sticking through.

Then, take the long end, stretch it along the flat side of the handle down to the base of the handle and begin winding it tightly, pulling it as tight as possible until it is wound all the way to the end.

You should have about 18” left over. At the base of the handle push the 18” end through the hole of the handle from the opposite side that the 12” end went through. Getting both ends of the parachute cord through the 5/32” hole proved to be quite a trick, but with a screwdriver, a small nail, a hammer, neddle-nose pliers, and 5 minutes of frustration, it finally went through.

Pulling it tight, tie a square knot at the top of the handle, then trim both ends at about 10”.  Make sure the ends are melted really well, and tie a knot to create a loop to go around your wrist. Total project time: approx. 3 hours

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2 comments on “Making A Knife”

  1. very nice easy to understand instructions. I created a brick-oven style coal forge for my sons to use, and we made them a makeshift anvil out of a piece of railroad track. One of their favorite hobbies is to make knives out of railroad spikes. They use bone or antler for handles in some cases. They would be interested in learning how to hammer out some Damascus steel. It's beautiful.