Learning to sharpen a chain

A well-sharpened chain is just as important as a powerful engine

We strongly recommend that you learn how to sharpen the saw chain yourself. The reason is that the chain must be kept sharp in order to cut efficiently, safely and with accuracy. Professional loggers sharpen their chains several times every working day, because they know that a sharp chain is just as important as a powerful engine.

How often should you sharpen the chain? That naturally depends on how much you use the saw, but when the chain starts to seem blunt it is usually time to sharpen it. The appearance of the chips gives a good indication of the chains condition. A sharp chain produces fine, regular wood chips, while a blunt chain just produces sawdust.

Equipment

You will need a round file, a flat file and a combination file gauge that fits your chain. Your Jonsered dealer has everything you need. A vice makes the task easier. Secure the bar so you have both hands free.

First a little theory

Each link in the saw chain works rather like a miniature plane. The effectiveness of the chain is determined by the difference in height between the cutter (1) and the raker (2). This height difference controls how deep the cutter bites into the wood. The raker should be about 0.50.8 mm lower than the cutter.

Cutters

You sharpen the cutters first. Lay the file gauge on the chain. The arrows on the gauge should point in the chain's direction of rotation. File the tooth using light, regular pushing strokes, at an angle of about 30 degrees to the bar. File each tooth the same number of strokes. File every second tooth from the right, and those in between from the left. A tip: If you have secured the bar in a vice it is easier to file every second tooth from one side, then turn the saw round and file the rest from the other side.

Rakers

Lay the raker gauge on the chain and use the flat file to file each raker flush with the gauge. The gauge has two positions: H for hard species of wood or frozen timber, and S for soft species of wood.

Warning: If you file the rakers without a gauge you could file them down too far. This will result in the chain biting too deeply, which increases the risk of kickback, excessive vibration and poor accuracy.