A chain saw sharpener keeps the cutting edge of a chainsaw's chain at its maximum sharpness. Sharpeners may be either electric or hand held. Whatever type of chain saw sharpener is used, the maintenance of a perfectly sharpened blade is absolutely crucial. Both the safety of the chain saw user and the quality of the cut wood depends on a perfectly sharpened chain that is filed at the correct angle.
Although a chainsaw is powered by a high speed electric or gasoline motor, the saw's chain teeth bite into the wood and do all the work. The hard chrome plating on the chain's cutting teeth must be filed with a chain saw sharpener often. If not, the hard edge will become dull and the user will have to exert force on the chain saw to cut and the saw could potentially produce poor quality cuts.
Forced exertion by the chain saw user can easily lead to faster fatigue. Research shows that many chainsaw accidents occur when users are tired. The exact moment a chain saw needs to be pushed to get it to cut is when the chain saw user should stop and use a chain saw sharpener on the chain. The cutting edge of dull chains can still look sharp, so a visual check of the chain is not an accurate way of assessing the sharpness of chain saw blades. A chain saw sharpener should be kept near the chainsaw at all times.
Dull chains can cause the chain saw to produce sawdust rather than the large wood chips that properly sharpened blades should be producing. Crooked cuts or the smell of burning wood are other signs that the chainsaw blade needs sharpening. The time between each use of a chain saw sharpener varies widely depending on the condition of the wood being cut. Moreover, chains are designed for cutting wood only, so if the blade touches dirt, metal, or stone, the cutting edge may be dulled within seconds.
Non-wood materials often grind the cutter down, but the sharp edge can usually be ground back with a chain saw sharpener. If the edge is less than 1/32 of an inch (1 millimeter), however, the chain will probably need to be replaced.
A chain saw sharpener is also called a jig. Electric sharpeners are fast, but hand held jigs are inexpensive and convenient. Hand held chain saw sharpeners are often round files with chiseled edges. Many chainsaw users use both types of jigs. Many beginners also like to use a rolling tool called a file guide that attaches to the chain, as it takes a lot of the guesswork out of chain saw sharpening.