Sharpening, Setting, and Using the Saw

North House’s class spends time on sharpening and maintaining the blade ¹. With a resharpenable blade, a frame saw lasts a lifetime.

The four steps

Clamp the blade in a saw vise with the teeth just above the jaws, and work in this order ²:

1. Joint. Run a flat mill file once along the tops of the teeth so they’re all the same height. Color the tips with a marker first; every tooth should show a small shiny flat.
2. Shape. File each gullet until all the teeth are the same size and the flats are nearly gone.
3. Set. Bend alternate teeth outward slightly with a saw set, one side, then the other, so the cut is a little wider than the blade.
4. Sharpen. File each tooth to a point, removing the last of the flats.

Rip or crosscut

The tooth shape depends on the job ²:

• Rip (along the grain): rake 0 to 8 degrees (8 is easier for beginners) and no fleam: file straight across, square to the blade, so each tooth is a tiny chisel.
• Crosscut (across the grain): rake 12 to 15 degrees and fleam about 20 degrees: angle the file across the blade, so each tooth is a tiny knife that severs fibers.

Norwegian museum saws include both rip-toothed and symmetric crosscut-toothed blades, many with teeth raked to cut on the push stroke ³.

Choosing a file

The file must fit the teeth. Pete Taran’s sizes: a 6-inch regular taper file for 5 to 5 1/2 points per inch, a 7-inch slim for 6 to 7, a 6-inch slim for 8, and a 6-inch extra-slim for 9 to 10 ². Blackburn’s 7-ppi blade takes a 7-inch slim ⁴.

Sawing with it

Hold a frame saw by one handle with the blade vertical, or with both hands for heavy ripping, and let the weight and length of the stroke do the work. Turn the handles to angle the blade when the frame would hit the work on a long rip. Start the cut gently against a thumb or a guide block, then use long, even strokes.

Care

Wipe the blade after use and keep it lightly oiled against rust. Check the tension each time you pick it up; cord stretches and slackens with humidity. When the saw starts to drift or needs pushing, it’s time to joint and touch up the teeth.

Try it

Joint and touch up your new blade even if it came sharp. Doing it once on a sharp blade, when you can see the original geometry, is the easiest way to learn it.