What We're Working On: My Knives
Slice an apple, open the mail, or cut yourself free when you’re wrapped in a rope being dragged by a wild horse, you never know when a good blade will come in handy. As a man who might find himself in any one of those situations, and as an avid DIYer, I make my own knives to suit my needs. “Never go anywhere without a knife.” That’s been a rule long before it was popularized on a hit TV show. In fact, the knife is one of the most ancient and fundamental of tools, second only to the hammer in age.
Choosing the Metal and the Fire
I like to start with repurposed raw materials—old horseshoes, worn out farrier’s rasps, dulled auger bits—whatever lengths of good and interesting steel I can get my hands on.
Horseshoes will get hot enough in my homemade coal forge, revamped from a wok and a blow-dryer. For more advanced steel, like the rasp and the auger bit, you need a gas fired forge unless you want to constantly feed and stoke the coals.
Changing the Shape
Put the horseshoe in the forge until it’s red hot at the top of its arc. Then I put the ends in two short lengths of pipe, just to give me something to grip, and twist the shoe straight. It’s a bit like working with taffy. (I’ve never actually worked with taffy.) Now it’s a bar with an S twist in the middle. One end of the S will be the handle and the other the blade. Back in the fire with it.
Let it go past red hot to yellow hot. Now you can really work the steel. Put the blade end on your anvil, holding the handle end with your tongs and beat the blade with your hammer. At this stage, it’s a four pound sledge, for maximum force. The anvil’s still cold, so it sucks the heat from the blade and you have to put it back in the forge a lot.
Forming the Blade
The blade beats down to the rounded shape of a dull butter knife at a fancy restaurant. The anvil heats up with every blow and the metal stays hotter longer. Time for the smaller ballpeen hammer. Smack the spine of the blade with the peen to encourage it into the shape you want. It wants to curve into a sickle, but you can convince it to straighten out. Use the ball side to pound the cutting edge, making it as thin and regular as you can.
Put the tip back in the fire and let it get past yellow all the way to white hot. Lay it on the anvil and set a chisel on the glowing tip to cut it into the shape you want. You can create a clip point, like a Bowie knife or a drop point, like a santoku, or any other design you choose. Whack the chisel with the hammer and chop off the unwanted material. It helps if you have three hands here.
Be gentle with the hammer forming the tip. This is really thin and delicate metal at the point. Tap the blade into the desired shape, and don’t rush it.
Shaping the Handle
With the blade done, you don’t have to do much hot work to address the handle. Sometimes I pound a pin through the nail holes to widen them, if the handle’s going to stay raw metal. Other than that, you can wait ‘til the forge is off and the metal is cool.
Quenching the Steel
Before that, heat the blade back to glowing and then quench it in a bucket of water. The water instantly boils. Do it again. Every time you do, the steel gets a little harder, setting the shape of the blade so it won’t tweak when you’re using it. I do it three or four times.
Grinding, Brightening and Finishing
Turn to your bench-grinder when the metal’s cool enough to work barehanded. Grind off any burs and refine the shape. Use your belt sander to really shine it up and go back to the grinder to put an edge on it.
If you’re going to cover the handle, I like to wrap it with steel or copper wire, over and over again, until you have a good, comfortable and well balanced grip. Sometimes I put the wire grip back in the forge and heat it up and hammer it a bit, sometimes I don’t.
That’s your knife. You could hammer out the groove and nail holes from the horseshoe, or beat the file points off the rasp, but I like to leave behind the marks that remind you what your knife used to be. This is a hand forged tool and there’s no reason to try and hide that.