The Complete Handbook of Chainsaw Bars

Chapter 1: Understanding Chainsaw Bars

A chainsaw bar is not a complex component, but it is a precise one. At its core, it is a long steel rail that guides a loop of chain at high speed around its perimeter. That rail must be machined to tolerances tighter than the width of a human hair in places. It must withstand the lateral force of a human pushing a 10-kg saw through hardwood, the heat of a chain passing over it at 25 meters per second, and the abrasive dust of wood fibers and dirt that the chain drags along its slots. A bar that fails to do this fails in one of three ways: it cuts crooked, it wears out prematurely, or it breaks and puts the chain, the saw, and the operator in danger. Understanding the bar is the difference between using a saw as a tool and being used by it.

The bar does not cut anything on its own. It is a guide and a mount. The chain is the cutting implement, the engine is the power source, and the sprocket under the clutch cover is the driver. The bar's job is to keep the chain running in a perfectly straight line, with the correct tension, and to position it so that the cutting teeth engage the wood at the right depth. Given that the chain travels at high linear speed, this guide function is not simple. Any slight bend in the bar, any irregularity in the