Build a Homemade Knife Sharpener

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The tool is sturdy yet compact, which is a welcome combination in a work area where space is at a premium.
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Diagram 1: Three-stone knife sharpener.
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Its multiple-stone arbor provides coarse, medium, or fine honing surfaces at the turn of a handle and secures each one in position with a simple horseshoe pin clamp.
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Diagram 2: Three-stone knife sharpener.

Maintenance is a must for your fine knives and tool blades; make it easy when you build a homemade knife sharpener. (See the knife sharpening diagrams and photos in the image gallery.)

Build a Homemade Knife Sharpener

To a person accustomed to working with cutting tools, a sharp edge is one of life’s little pleasures. And few whetstone wielders would deny that the triple-face sharpener shown here is a great new twist on an old grind.

To begin with, the tool is sturdy yet compact, which is a welcome combination in a work area where space is at a premium. In addition, its multiple-stone arbor provides coarse, medium, or fine honing surfaces at the turn of a handle and secures each one in position with a simple horseshoe pin clamp. Furthermore, the arbor rests in an oil- or water-filled pan that continually bathes the two unused stones in their appropriate lubricating medium. If you wish, you can also make a protective cover that doubles as a ramp for use with the roller-type chisel- and plane-blade sharpening guides popular with many woodworkers.

If you think you might like to give this inexpensive multiple-stone hone a try, you’ll need to gather up a 32 inch length of 1 by 4, a piece of 3/4 inch plywood or one-by that’s at least 4-1/4 inch wide and about 14 inch long, a block of hardwood measuring 2 inch by 2 inch by 3 inch , a 1/2 inch by 12 inch steel shaft, a 3/32 inch by 1-1/2 inch expansion pin, a 1/2 inch -bore, 3 inch -diameter pulley, a 3/16 inch by 13 inch steel rod, a 1/2 inch by 9-1/2 inch rubber hose with a 3/16 inch orifice, a 1/8 inch by 3/4 inch by 20-1/4 inch piece of aluminum flat stock, a 2-1/2 inch -deep, 5-1/4 inch by 9-1/4 inch bread pan, three 3/4 inch by 2 inch by 7 inch sharpening stones in your choice of composition and grade, and the assorted fastening hardware called for in our illustration.

The box is easily made by first ripping the 1 by 4 down to 2-3/4 inch in width, then cutting it into two 5-1/4 inch and two 10-3/4 inch pieces. Drill a 1/2 inch hole, centered and 3/8 inch below one edge of each of the shorter boards, then fasten the box sides to the ends using eight No. 6 by 1-1/4 inch flathead wood screws. (Take the time to countersink the heads and fill the holes, too.)

Next, push the pan firmly into the frame and mark the positions for the holes that will receive the arbor shaft, using the 1/2 inch bores in the ends as guides. Remove the pan to drill the openings, then set it back in place and secure it to the box with four No. 6 by 1 /2 inch wood screws fastened through the rim lip.

To make the arbor, you’ll first need to cut the hardwood block into an equilateral triangle with 1/2 inch -wide flats instead of corners. Then, by carefully dividing lines struck between the centers of each opposite flat surface, you can determine the exact center of the block and bore it longitudinally with a 1/2 inch Forstner or auger bit. With this done, cut the piece into three 1 inch -wide sections to make a set of triangles.

Before you install the blocks, slide one of them onto the shaft until it’s at a point that will correspond with the center of the bread pan when the arbor’s in place. Then drill a 3/32 inch hole through a wide flat, the middle of the rod, and part of the block behind it. Remove the wood, and slip the shaft into the holes in the frame and pan, sliding the blocks on as you go and making certain the drilled piece is in the center.

Once the shaft is positioned in the frame, cut your aluminum stock into three equal pieces and arrange the blocks so the middle one is lined up with the hole in the axle and the end sections are centered about 6 inch apart. Tap the expansion pin into the cross-bored socket, then turn the other two blocks so the flats are in line. Set an aluminum strip on one row of narrow flats and drill 3/32 inch pilot holes through the metal and into the wood. Enlarge the openings in the strip, insert the aluminum screws, then repeat this procedure on the other two rows.

To fasten the stones in place, simply lay them on the broad flats and tighten the strips so their edges catch the lower shoulders of each stone. (You may need another pair of hands to accomplish this.) If you plan on using stones larger or smaller than the ones we chose, you’ll have to adjust the size of your hardwood triangles accordingly, and perhaps that of the strips as well . . . but the method of securing the abrasives will remain the same.

At this point, you can attach the pulley to the exposed end of the arbor shaft and mark the location of the three 7/32 inch holes that hold the horseshoe clamp. These should be drilled equidistant from one another so that any pair will be even with the top of the pan as the pulley is rotated into position. Cut an 8 inch piece from the 3/16 inch by 13 inch steel rod and bend it into a U shape with a spread to match the holes, taper the rod’s tips, then reorient the pulley on the shaft so the clamp and one of the stones are on the same plane. You can make a simple grip by bending the leftover section of rod into an arc and using it to join the ends of the rubber hose to form a loop around the pulley groove.

The sharpening guide ramp is assembled with basic butt joints. First cut your 4-1/4 inch wide 3/4 inch board into 1-5/8 inch, 3-1/4 inch, and 8-1/2 inch lengths, then use a coping saw to make 1/2 inch -wide slots in the center of the legs . . . 1 inch deep in the shorter piece, and 3 inch deep in the longer one. (You can terminate the cuts by predrilling a 1/2 inch hole at the top of each slot.) Attach the platform to the legs with No. 6 by 1-1/4 inch flathead wood screws, fill the holes, and check to make sure the surface is flush and even with the stones when the ramp is in place. With that assured, coat the tool’s wooden parts with varnish or polyurethane to provide a working finish.

Perhaps one of the nicest features of this bench tool is that when it’s filled with an inch or so of oil or water lubricant, it’s heavy enough to stay put without being clamped . . . and its reservoir keeps the stones moist for instant use when needed. But its primary value is that it provides a convenient method of maintaining a variety of cutting edges, a workshop chore that’s all too often neglected.