Knife Maker Tool Shop

Learn about the knife maker tool shop and the variety of tools you can use to design, build and sharpen knives.
By John Vivian
April/May 1996
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You can adapt any number of woodworking tools to shape and polish a blade and to form and attach handles.
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The knife maker tool shop shares information on creating and maintaining knives. 

Knife Maker Tool Shop

You can adapt any number of woodworking tools to shape and polish a blade and to form and attach handles to the tang. But the one knife-making step that few country workshops can handle is the full range of heat-treating. The blade can be tempered—heated to about 500 degrees Fahrenheit and cooled slowly so it will hold an edge but not be so brittle as to shatter—in your kitchen oven. You should get a little $3 oven thermometer to assure that temperatures are correct. But before tempering, the steel must be hardened by heating it to 1500 degrees Fahrenheit, then quenched rapidly. No ordinary kitchen range gets half that hot.

Knife makers heat steel in a smith's coal forge, a gas knife makers oven, or an electric annealing oven that costs $400 to several thousand dollars. Spending that much to make a knife or two is unrealistic, but you can have the high temperature work done at the local high school metal shop or a metalworking job shop that specializes in heat treating. If you anticipate having to cut and weld steel often enough, you can invest $150 in an oxyacetylene torch set and learn to use it safely and effectively.

I use four $10 propane soldering torches in a temporary knife oven fashioned from loose fire brick with an angle iron lintel over the front opening. The interior space is a foot to a foot and a half wide depending on the blade, six inches deep, and one brick-thickness high. With torch nozzles poked through holes filed into end bricks, the oven will generate up to 2500 degrees welding temperature in knife-blank-sized pieces of carbon steel. It can take time to heat large blades, so I keep several fresh bottles of fuel at hand. The fourth torch is mainly used to maintain heat when a tank suddenly goes dry and needs replacing (but not till the nozzle cools).

Long-handled pincers of some sort are needed to handle hot metal. Blacksmith's tongs designed for an open forge are too gross for the little oven. So I use long handled channel-lock pliers and wide-mouthed welders locking pliers (Vicegrips).

Thick leather gauntlets, leather apron (or thick old clothes), and steel-toed boots are desirable, and shatterproof eye protection is absolutely essential. If you heat flat steel it will warp, and to hammer it flat, you need a good hammer and an anvil. I use a one-pound ball-pein hammer and a two-and-a-half-pound blacksmith's cross-pein hammer—and for tough stuff, a short four-pound logsplitting maul. As an anvil for small jobs, I use the flat and small horn of my big six-inch vise (though it is cast from soft steel and will dent under blows from a tempered-face hammer). An 18-inch-length chunk of old trolley rail is better. Scrounge at your local junkyard for anvil material as well as knife stock. Just be sure the anvil is well seated so it won't wobble when struck.

A professional knife maker will refine blanks' shape on a pedestal-mounted, standup belt grinder and large revolving grinding wheels on a high-speed motor. High polish is obtained with felt buffing wheels on a dedicated grinder or arbor, belt driven by an electric motor, and a final fine edge is obtained on an assortment of hand and mechanized honing stones and strops.

Unable to justify the cost of a professional metalworking shop (even if I had the dough) I wanted to adapt woodworking tools that I use frequently to form steel, so looked into the characteristics of knife-making tools. Like woodworking sanders, every metal-grinding device is a compromise between speed of stock removal and tendency to overheat through friction. Controlling friction is especially critical at final knife-sharpening stages because if you push a thin knife edge too hard against any cutting grit, you'll overheat the steel and lose the temper you've put into it with careful heat treatment.

I found that a metal-cutting band saw runs slowly (at about 80 blade-feet per minute)—but even so it must be cooled and lubricated with motor oil or white cutting fluid. Industrial-quality belt-grinders move a 48-inch belt around two or three pulleys (so it offers at least 18 inches of exposed work surface and cools rapidly) at 6500 feet/minute using a 3500 rpm electric motor. Grinders come in fast (3500 rpm) and slow (1800 rpm) speeds. The high speed is best for fast metal removal and the low speed best for final sharpening.

As luck would have it, most bench-mount woodworking wide-belt sanders run at 3500 rpm—ideal for fast metal removal. Most stationary thin belt or disc sanders or handheld belt sanders run at the slower speed, which is best for fine finishing. The metal ID tag on your 6-inch or 8-inch rotary bench grinder will tell its speed. I got a Taiwan-made low-speed grinder to sharpen chisels and other edged tools, and it runs at the safer slow speed. I also have and can recommend Woodworkers Warehouse (retail stores and a major mail-order seller) private brand of belt/disc sander. Their $120 Reliant with a 48-inch belt, 8-inch disc compares with 30-inch/6-inch competitive models—that cost more than twice as much. Especially in metal working, the longer belt is desirable for cooling purposes. Exclusively, to my knowledge, the Reliant also has a dual pulley system for inside-sanding/grinding and to provide backing wheels as well as a flat platen behind belt to push work against for curves and faster metal or wood removal. Taiwan quality (meaning good in the essentials, less good in the finish and fit-type fine details) but a really great value.

If your budget is really limited, look at the Ryobi D38VSR 3/8-inch Electric Hand Drill. At under $40, it is a bargain and less than half the cost of the competition. This is the only 4-amp (112v AC—plug in) electric drill I could find with the ability to hold (hands-off) the two speeds a knife maker needs. Clamped stationary, it will do every knife-making grinding chore when fitted with a 4-inch sanding drum, abrasive stones, sanding disc, and buffing wheels. You can buy a $25 adjustable tool rest to fasten in front of it at many hardware outlets and through most mail-order woodworking tool catalogs.

The faceted, sharp-edged cutting minerals cemented to belts and discs must be harder for metal than for wood. Backings differ as well; woodworking backings are typically reinforced paper while metal needs a stronger, more heat- and tearproof woven fabric—like the familiar difference between sandpaper and Emory cloth. Industrial metal-cutting belts are 48 or 60 inches long and 4 inches wide or larger ... but most home wood-shop belt sanders run 30, 36, or 42 inches long, one- or two-inch wide belts. They will do the job, just more slowly.

For about $50 you can get an eight-inch expanding drum that attaches to a grinder. Belts are harder to locate but come in all popular grits.

I also have a set of small files and a hand-held Dremel Moto-tool that is helpful to finish up hard-to-access crannies such as curves in hilts and pommels. A good metalworking vise is essential if you will be subjecting blades to high heats, as are a collection of welder's clamps and ordinary and locking pliers. I kept burning my woodworking bench, so I located a square of stone to rest hot blades on. First it was nothing but an old roofing slate. Now I have a good slab of Vermont marble. Soapstone or any soft stone will do.

Woodcutting grit can be something as common as quartz—plain sand—while metal cutting grit is super-hard silicon carbide, aluminum oxide, or even diamond dust. You can buy metal-cutting belts in any length and width you specify and in coarse 60, medium 80, fine 100, and superfine 120, 240, and 360 grits. Mail-order outlets advertising in the woodcraft magazines sell belts for under a dollar apiece—half the retail price.

In the best grinding wheels, grit is contained in a soft medium so it will abrade before it burns the metal. I use Norton wheels—a name brand and expensive but last for years, and I'm confident that these will hold together at high speeds.

To make handles, power or hand woodworking equipment is more than suitable. A jigsaw, bandsaw, or small hand-powered coping saw will split out and shape the scales (halves) of a two-part handle. One-piece handles must be drilled to accept a tang. Any hand drill with a long bit will do.

Scale handles are fastened with rivets or scale pins that are secured with a small tack hammer and hand-anvil—that can be nothing but the hammering end of a cold chisel. Attaching one-piece handles with a scratch-made screw-on pommel end requires a small tap and die set that is too complicated for a few knives. Epoxy cement does as well or better and takes less investment and skill—even if it isn't an authentic pioneer technology (they used hot hoof glue for handles and leather work).


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