Tip #19
Sharpening Woodworking Tools (continued)
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Sharpening Bench Chisels

A bench chisel may be one of the most used and most abused tools in the shop. Along with chiseling, it's sometimes used as a pry tool, a wedge, or even a substitute for a screwdriver. Because of this, the bench chisel could be the most sharpened tool in the shop. To sharpen bench chisels, they must be ground, then honed.

Grinding Bench Chisels using the Sharpening Guide
The Shopsmith Sharpening Guide mounts on the disc sander, belt sander and the strip sander and is used to grind bench chisels. Set up the machine you will be using and grind the chisels according to the applicable instructions below. To determine the sharpening guide angle settings, refer to Table 24-1.

Disc Sander Setup--Mount the sharpening guide on the Mark V worktable and adjust the worktable height. Mount the sharpening guide to the worktable only. Mounting the guide to the extension table will not allow the required 9° table tilt.

Tilt the worktable 9° toward the abrasive. To adjust the sharpening guide to the desired angle setting, lay the flat bottom of the bench chisel against the right-hand wall of the second station. With the tip of the chisel against the abrasive, pivot the sharpening guide until the bevel of the chisel sets flat against the abrasive. Secure the sharpening guide in place.

Warning: Position the sanding disc to within 1/16" of the sharpening guide. Then secure the power plant lock.

Belt Sander Setup--Set up the belt sander vertically. Mount the sharpening guide to the table and secure it by tightening the two lock knobs. Tilt the table 9° toward the table. Warning: Position and secure the sharpening guide to within 1/16" of the belt and secure the table locking setscrews.

Figure 24-8. Draw an index line 3-5/8" from, and parallel to the platen.

Strip Sander Setup--Because there are no table slots or mounting holes in the strip sander table, the sharpening guide must be clamped to the table. An index line is used to align the guide. Draw this line 3-5/8" from, and parallel to the platen as shown in Figure 24-8.

When setting the table tilt and the sharpening guide angles, hold the chisel against the left wall of the second station of the guide. Position the hole in the rear of the sharpening guide and the angle setting indicator directly over the index line.

Figure 24-30. Position the sharpening guide within 1/16" of the belt and clamp it to the table.

Slide the sharpening guide along the line until the chisel in the second station of the guide is in front of the belt. Warning: Position the sharpening guide to within 1/16" of the belt. Then clamp the sharpening guide securely to the table (Figure 24-30).

Grinding Bench Chisels--Turn on the machine and set the chisel in the second station of the sharpening guide. Slide the chisel into the abrasive while holding it firmly against the left wall of the station. Hold the chisel against the abrasive momentarily, then back it away (Figure 24-31).

Figure 24-31. Slide the bench chisel into the abrasive. Hold the chisel there momentarily, then back it away.

Repeat this several times until any damage to the cutting edge is removed.

Grinding Bench Chisels using the Grinding Wheel
The Shopsmith Grinding Wheel mounts on the Mark V. Select the proper wheel for the severity of the cutting edge damage (coarse for nicks and a badly worn cutting edge and fine for routine grinding). Set up the grinding wheel according to the Owners Manual that came with the Grinding Wheel Accessory.

The bench chisel can be ground on the front or on either side of the grinding wheel. When the chisel is ground on the front of the wheel, the bevel will be hollow ground. Because this hollow ground edge is so thin, a secondary bevel will need to be honed on the cutting edge. This will be done with a coarse sharpening stone.

When the chisel is ground on the side of the wheel, the bevel that is left is flat and can be honed to a razor sharp cutting edge without the need for a secondary bevel. Warning: Grinding on the side of the wheel is tricky because there is nothing but feel to guide the chisel to the proper angle and is not the best approach. Use extreme caution.

Figure 24-32. Set the angle so that the wheel is centered on the flat bevel. Tighten the wind nut securely.

Grinding Bench Chisels--Hold the chisel on the tool rest, loosen the wing nut and tilt the tool rest so the bevel sets against the wheel. If the chisel has a flat bevel, set the angle so that the wheel is centered on the flat bevel. Tighten the wing nut securely (Figure 24-32). Remove the chisel from the tool rest and make sure the speed dial is set to “Slow”. Then turn on the Mark V and set the speed dial to “R” (3400 RPM).

Figure 24-33. If the chisel is narrower than the width of the wheel, hold the chisel there momentarily, then back it away.

If the chisel is narrower than the width of the wheel, slide the chisel up into the wheel, hold it there momentarily and back it away (Figure 24-33).

If the chisel is wider than the wheel, follow the instructions above, except you must slide the chisel from side to side after it comes in contact with the wheel (Figure 24-34).

Grind away only enough metal to remove any damage. This will complete grinding the primary bevel. To create the secondary bevel, hone the chisel.

Figure 24-34. If the chisel is wider than the width of the wheel, move the chisel side to side, then back it away.

Honing Bench Chisels
The bench chisel has a bevel ground on one side of its cutting edge. This bevel as well as the flat bottom face must be honed. This will remove the grinding burr and sharpen the cutting edge.

Start with a coarse hone and moderate-to-heavy pressure to create the secondary bevel. By repeating this procedure on progressively finer hones you will be able to hone the cutting edge razor sharp.

Figure 24-35. Hone bench chisels on oil stones, by pointing the cutting edge in the same direction you are sliding the chisel.

Using Oil Stones and Diamond Hones--Hold the bevel of the chisel on the hone. Slide the chisel over the hone with the cutting edge pointing in the same direction you are sliding the chisel (Figure 24-35). Think of it as trying to shave off a thin sliver of the hone. Turn the chisel over and repeat the procedure on the flat side.

Using Water Stones and Rubber Bonded Abrasives--To hone bench chisels With a cutting edge Wider than 1/2", follow the oil stones and diamond hones instructions.

Figure 24-36. For narrow chisels, on water stones, point the cutting edge away from the direction you are sliding the chisel.

For bench chisels with narrower cutting edges, slide the chisel over the hone with the cutting edge pointing away from the direction you are sliding the chisel (Figure 24-36). Think of it as trying to smooth over the surface of the hone. Turn the chisel over and repeat the procedure on the flat side.

Continue to Grinding Planer and Jointer Knives
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