For most people who have to do work outdoors, the chain saw is a vital tool. The chain saw is able to cut through all types of wood significantly faster than any handsaw, making clearing brush, limbs and even felling entire trees quicker and safer. The chain saw's blade is an actual chain with sharpened teeth on the outside edge. The saw accelerates this chain around a guide bar at extremely high speeds, allowing the "blade" to cut through wood.
While there are many different types of chain saw chains in existence, they all break down into two basic types: the round-tooth blade and the square-tooth blade. The round-tooth blade is also called a chipper tooth and has a rounded backside that curves over to the top of the tooth. This style is a good all-purpose blade that is easy to sharpen and keeps its edge longer.
The square-tooth blade is also called the flat-top or the chisel-tooth. This style of tooth is flat on the back and the sides and sports better cutting performance. The downside to the square-tooth is that it is harder to sharpen and loses its edge quicker.
In addition to the teeth, the chain can come in several different styles as well, dictating the frequency of teeth on the chain. The standard chain is also called the "full house" or the "full complement" and features the full amount of teeth possible on the chain. The skip chain has every other tooth removed, and the semi-skip is a compromise between full complement and skip chains. The type of chain depends a lot on the type of wood and the size of the chain saw. Generally, the skip chain will allow for faster cutting through soft woods, giving chips and other wood residue time to clear the cutting area and preventing jams, but requiring a larger and more powerful saw.
With every chain saw, regardless of chain, there is the danger of a kickback. With the chain moving at high speed, the teeth can jam on something, causing the chain saw to kick back toward the user. Most consumer-grade chain saw chains contain features that help prevent kickback from occurring. There are more aggressive chains available that remove these features for quicker sawing, but these types should be used by experienced professionals only.
A chain saw is a very dangerous tool. Regardless of the type of blade being used, extreme caution should be observed at all times. Even with a low kickback chain it is still possible for a kickback to occur. Keep full control over the saw at all times. Chain saw safety equipment should be worn while operating the saw and proper sawing technique always observed to help prevent serious accident.