Cutting chain comes in a bewildering variety of configurations, but these come down to a few key dimensions for replacement or specification purposes.

gauge: the gauge of the chain is the thickness of the drive links, and is dictated by the gauge of the bar it must be run on. Usual gauges are .050" (1.3 mm) - .058" (1.5 mm) and .063" (1.6 mm). Chain and bar gauge must match; a chain that is too large will not fit, one that is too small will fall sideways and cut poorly.

Pitch: the pitch of the chain is the average distance between two rivets. As the distance between rivets varies, the pitch can be measured by measuring between three rivets and dividing this distance by two. Usual pitches are 0.325", 3/8" and 0.404". 3/4" is used for harvester applications, and very rarely for handheld cutting. the pitch of the chain must match the drive sprocket, and the nose sprocket (if fitted).

length: a chain loop must be of an appropriate length in order to run safely. This is described by the number of drive links. This number is determined by the length and type of bar, the sprocket size and the overall configuration of the saw. For replacement purposes, simply count the drive links on the old chain.

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Chain Saws