Clean Cuts

Sharpening tips for your woodworking tools

Sharpening Jointer, Molder and Shaper Knives

For these reasons, we recommend that you not attempt this and rather, regrind your Jointer Knives using the Shopsmith Disc Sander setup. We offer you both a fast, easy way...and a slightly more involved, though less expensive way to do this, based on a built-it-yourself Sharpening Jig.

No matter which way you decide to go, start by disconnecting your MARK V and Jointer from the power source, then remove the Knives.

The fast, easy way

Fig. 4. Use Shopsmith's Planer/Jointer Knife Sharpener with the Conical Sanding Disc to sharpen your Jointer or Planer Knives.

The best regrinding solution for your Shopsmith Jointer Knives is provided by Shopsmith's Planer/Jointer Knife Sharpener, used in conjunction with our Conical Sanding Disc (See Fig. 4). The Sharpener attachment has been carefully engineered to hold your Jointer or Planer Knives at precisely the right angle during sharpening. You'll get a simple, fail-safe Sharpening Attachment, with easy-to-follow, step-by-step instructions.

Fig. 5. A jig to regrind a 45-degree bevel in Jointer Knives with the Shopsmith Disc Sander. Cut a 1/8" saw kerf at a 45-degree angle in a scrap piece of 2" x 4". Add two wood screws with washers to clamp the Knife in the kerf.

Just set up your MARK V in Disc Sanding mode with the Conical Sanding Disc and 150-grit Sandpaper. Then, simply follow the instructions that are included with the Sharpener.

The build-it-yourself jig
Start by building the jig shown in Figure 5. Next, set up your MARK V in Disc Sander mode with 100 to 150-grit sandpaper. Lock the Worktable and Sanding Disc 1/8" apart. Offset the Rip Fence about 1/16" to the right by turning the Allen setscrew in the right side of the Rip Fence Base (See your MARK V Owner's Manual or the Disc Sanding section of Shopsmith's Power Tool Woodworking for Everyone textbook for detailed instructions.)

Clamp the first Knife into the Jig by inserting it into the saw kerf and tightening the two wood screws. Make certain that the base of the Knife sits flat on the bottom of the saw kerf. Failure to do this will result in the blade being reground at an improper angle.

Next, adjust the Rip Fence to hold the jig so the Knife just barely touches the Sanding Disc on the downswing side, near the front edge of your MARK V's Worktable. Lock the Rip Fence into position. Cover the MARK V's Way Tubes to protect them from flying bits of metal and abrasive particles.

Fig. 6. Using offset fence technique, grind Knives to remove nicks.

Wear Safety Glasses or a Protective Face Shield to protect your eyes from flying debris. At SLOW speed, feed the jig (with the Knife inserted) towards the Disc...starting at the back of the Worktable and working your way forward (See Fig. 6). Remember...the Sanding Disc should contact the Knife only slightly...and only at the outfeed (downswing) edge of the Worktable.

Always move the jig slowly...taking light passes...yet not so slowly that the metal begins to heat-up. If the metal starts to turn blue, it will lose its temper and therefore, its ability to hold an edge.

If you determine that the Knives still need more grinding after making several passes without adjusting the Disc, place a strip of paper between the jig and your Rip Fence and repeat the above process. This technique will allow you to advance the Knife very precisely and minutely towards the rotating Disc. Up to three strips of paper can be used at one time, although it's most likely that only one strip of paper will be required.

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