Woodworking 101: Basic Sharpening
Sharpen a Plane Blade
There are many ways to sharpen plane blades, and woodworkers have strong opinions on the best technique. Here is a simple, reliable method to achieve a sharp edge. It takes just three waterstones, an inexpensive jig and a few minutes.
1. Get a flat back.
While some blades come with a flat back, you still need to polish it. Stick a magnet over the bevel to improve your grip. Start polishing the back on a #1,000-grit stone, then move to #4,000 and finish at #8,000. If the back needs serious work, start flattening on #80-grit sandpaper stuck to a flat surface.
2. Check the edge for square.
Confirm the primary bevel is ground straight across. If it is not square, regrind the bevel.
3. Put the blade in the jig.
For most blades, we use a side-clamp honing guide. Because this jig has a narrow wheel, you can use finger pressure to hone the edge straight or with a slight camber. Set the plane blade in the jig at 30° using a protractor. Then you can make a simple stop-block jig with two scraps to easily set the blade next time.
4. To hone a straight secondary bevel.
Use equal finger pressure at each corner to hold the blade edge flat to the #1,000-grit waterstone and pull it toward you 10 times. Observe the edge. Feel the back for a small curl of metal (This is called the burr). If the grinding scratches are gone, spritz off the jig’s wheel and switch to a #4,000-grit stone. Hone, observe, repeat. Then move to #8,000 grit. Now jump to Step 6.
5. To create a cambered secondary bevel.
Follow the grit progressions in step 4, but take 10 strokes while applying finger pressure at one outside corner of the blade. Repeat on the other corner. Now shift your fingers one-third of the way in from a corner, and take six strokes. Repeat on the other side of the blade. Now apply pressure to the middle and take two strokes.
6. Remove the burr from the back of the blade.
Place a thin ruler across one edge of your #8,000-grit stone and place your blade across it. This will raise the blade less than 1° and concentrate the hone on the working edge. Hone the back by working the blade on and off the far edge of the stone for about 10 passes.
– From the Winter 2009 issue of Woodworking Magazine; Techniques by David Charlesworth, illustrations by Mary Jane Favorite