Crosscut Saw Manual

Filing the Saw, continued

Pointing Up Cutter Teeth

To point up the cutter teeth, tilt the vise away from you at about a 45-degree angle. With the vise tilted, the flat spot on each tooth caused by jointing should appear bright. To accomplish this, place the main light source in front so you can see a good reflection from the flat spot. A wide set of windows (preferably without direct sunlight) works well. Two 4-foot fluorescent lights mounted end to end on a wall supply uniform lighting regardless of weather conditions. Avoid point sources of light such as incandescent bulbs and direct sunlight.

For filing the teeth, a 7- or 8-inch special crosscut file is used. The tooth shape illustrated below is good for general purposes.

A good general-purpose cutter tooth

The stroke should be more nearly up and down than across the tooth. The main point to keep in mind when filing a cutter tooth is to file just enough to almost make the flat spot from the jointing operation disappear. Overfiling upsets the relationship between the cutters and the rakers and also results in a weak point. A slight rolling or rocking motion of the file generates a slightly convex filed surface and results in a more durable tooth. Because of the set, a tooth whose filed surface is flat will develop a concave cutting edge and a thin, weak point.

A poorly filed cutter tooth

The more pointed a tooth is filed, the deeper it will sink into the wood and the "hungrier" a saw will be. However, a sharply pointed tooth will wear faster than one less sharply pointed. The consensus is that there should be less bevel on a cutter tooth for hardwood than for softwood.

Tooth shapes

As the tooth is being filed, it is a good idea to periodically remove the burr that forms on the back side of the tooth, because the burr can obscure the true tooth shape. Remove the burr with a whetstone or a light stroke of the file across the tooth back--just enough to remove the burr. The back side of the tooth must not be filed, because it may cause the saw to bind. The burr also can be removed with a piece of hardwood.

Filing a cutter tooth

After all the teeth are filed, hold a fine stone flat against the saw. Pass it over the teeth to remove any residual burrs, especially at the tips of the teeth. A burr under the spider would cause an error in the tooth set.