How to Make a Hunting Knife

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In other words, grinding (like life itself) quickly becomes self-corrective, due to the immediate feedback that you'll develop through your sense of touch (a process of communication). Strive for this skill, work on it, as you hone your blade approximately 90 percent complete. Then save the last 10 percent of stock removal for the final regrinding/polishing steps below.

Dropped Finger Guard

Whatever kind of blade you're making, grind it carefully and evenly. If it is of a "dropped design," however, and the dropped portion is to serve as a finger guard, remember to leave the last 1/8-inch or so on the end of the blade nearest the handle ungrounded. Make sure that this area (where the grinding stops at the base of the blade to form the guard) is faced off very precisely and sharply.

Regrind the Blade

Now begin to refine the shape of the blade by working it over the wheel of a belt grinder. Remember: If you turn the point or edge of the blade into the belt, the wheel will catch it, doing damage to the belt, the blade and possibly your hands. Be very careful about this.

Use a 40-grit belt to bring the blade down close to the thickness you desire and to take out the marks left from the high-speed grinder.

This, of course, will leave a set of much finer 40-grit tracks, so regrind the steel again with an 80-grit belt to remove the 40-grit marks. Try to get the blade as nearly perfect as you can this time through, because it'll be the last full grinding operation that you'll use on the steel prior to tempering it. When you finish with this step, the blade should look just about perfect (except for its rough 80-grit texture).

Then, before tempering, grind around the silhouette of the entire blade (tang included) with a 120-grit belt to minimize the stress on the edges of the steel during the heat-treating process.

The Heat-treat

There are three steps in completely heat-treating a carbon steel blade: [1] hardening, or heating the steel to a cherry red and quenching it in oil or a brine solution, [2] tempering or drawing, which takes the brittleness out of the hardened steel by slowly heating it in an oven until it turns a certain prescribed color, and [3] annealing of the tang and backbone of the blade, that is, heating these portions of the shank to a deep blue, followed by a slow cooling that makes the steel tough and flexible so the blade cannot snap.

Hardening

To harden your steel, bring the entire blade to an even bright red (1,425 to 1,450 degrees Fahrenheit), then plunge it into a quenching bath of tempering oil (if you don't have the "real thing," try a half-and-half mixture of used crankcase oil and diesel oil). Be sure the tongs or rack holding the blade do not cover a crucial area of the edge (they must touch only the back of the blade or its tang).

You can use an acetylene torch for medium and small knives, but a small, ceramics-type electric kiln is preferable for knives of all sizes. A gas-heated kiln works well if it is large enough to get the knives in and out of. The unit need only be slightly longer than the length of the longest knife blade, and only about four inches wide for optimal heating speed.

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