Unsourced material may be challenged and removed. Its key differences are sharp cutting teeth on the outside of the chain loop, and flat drive links on the inside, to retain the chain on the saw’s bar and allow propulsion by the engine or motor. Modern chains designed for high power, high-speed sawing applications will vastly outperform older designs, while allowing a far greater degree of safety and reliability in use. In order to operate properly, the depth to which each tooth cuts must be limited to avoid it binding in chain sprocket dimensions pdf stihl wood.
Scratcher chain, like the teeth on a hand saw, simply uses a multitude of teeth to prevent individual teeth from sinking too far in without undue pressure on the bar. This has two distinct advantages over scratcher chain – it enables the use of fewer cutters per unit length of chain, which allows for shorter downtime for sharpening, and produces a more “open” chain layout, allowing far better clearance of chips and debris from the kerf. Individual depth gauges on each tooth also enable the use of skip chain. Skip or semi-skip chain has a further reduction in the number of teeth and is used for applications where much debris is produced, such as ripping or cross-cutting very large sections of wood.
A section of “scratcher” chain on a bar nose, showing the tooth layout. A section of “scratcher” chain showing the large number of teeth compared to modern chain. Very early chainsaws used tooth configurations very similar to conventional hand saws. They were inefficient and slow in use, and were soon superseded by chipper chain. They required great skill and a lot of time to sharpen in the field leading to extended downtime between sessions.
10 chipper chain, note the long curve between the top and side plates. Chipper used a tooth that was curled over the top of the chain, with alternate teeth pointing left and right. Ahead of the tooth was a depth gauge, which allowed for good clearance around the tooth for chip clearing while limiting the depth of cut and preventing grabbing or overloading. Chipper chains are sometimes used for dirty work, since their very large working corner allows the cutter to retain its effective sharpness for a long time in abrasive conditions.
Chisel chains have a high kick-back risk due to missing safety chain elements and are more sensitive against dirt. The semi-chisel chain has teeth with rounded corners formed by a radius between the top and side plates. Variation of the semi-chisel chain is “Chamfer chisel” chains made by Oregon. They are similar to semi-chisel design but have a small 45 degree chamfer between the plates rather than a radius. Performance is similar to good semi-chisel. Semi chisel chains have a lower kick-back risk.
These chains are available for consumer, semi-pro and professional saws. Low-profile chains are chains with low teeth and safety elements between teeth. These chains are used on consumer saws for non-experienced operators. These chains are more insensitive against dirt, but require more frequent sharpening.
The chipper chain is similar to the semi-chisel chain. The key differences between are the size of the radius at the working corner. In cross-section a chipper tooth looks like a question mark, having a full radius over the whole cutting portion of the tooth, whereas a semi chisel design is more like a number “7” with the top-right corner slightly rounded. There are also different arrangements of teeth on the chain. Chain has a left cutter, drive link, right cutter, drive link arrangement and is used for most applications. Has a left cutter, drive link, drive link, right cutter arrangement. Fewer teeth require less power to operate.