When using a chainsaw there is nothing more annoying than discovering that you have a blunt chainsaw. You have gone to the trouble of fueling and topping your chainsaw with oil, it then starts like a dream and runs smoothly – you then hit the wood and discover instead of cutting it is knowing its way through. Not only is a blunt saw ineffective it can also be a safety issue for the user.
Trying to work with a dull or poor cutting chainsaw means you spend too much time thinking and considering the end result, it can also take a physical toil on your body. Having a poor performing chainsaw can produce excess vibration and will require a greater effort on your part to cut the offending wood.
There is little information or knowledge out there around the basics of how to sharpen a chainsaw. A little information and knowledge of the basics of sharpening within the manufacturers guidelines which may assist in the sharpening dilemma, and although there are advanced task specific sharpening methods, the best place to start is with the basics.
There are several different elements to successfully sharpening a chainsaw; these will include close attention to detail, consistency of angles and an understanding of the function of the cutting teeth in a chainsaw.
You can use a file to sharpen the teeth of the chainsaw. However, you have to make sure you use the correct size for the chain you are sharpening. Using a too large or small file can damage the chain. You can usually get the information for the right size file from the manufacturers guide or the shop you purchase the saw from. As a general guideline you should use a file that extends up to 20 per cent above the cutting teeth. You should also file the cutting teeth from the inside out which avoid metal filings going down into the chain channel bar.
It is advisable to sharpen chain teeth on both sides using the right file and gauge for the job. It is also advisable to use a vice to hold the chain and bar while sharpening, ensuring the chain can rotate freely though.
The cutting teeth on a chainsaw are actually the ones that sever the wood fiber chip by chip, after they have been properly set up for the right bite size. The point of starting corner of the tooth begins the cut by entering the wood, the top plate and attendant angle begins to chisel a chip of the wood down into the gullet as the side plate of the tooth separates it.
The original designs of cutter teeth are based on the observations of an experienced logger called Joe Cox. He made the discovery while watching a beetle remove wood during a lunch break. Cox then went on to found the Oregon Cutting System which most chainsaw cutting mechanisms are based upon.
Operators of a chainsaw who observes the chips being emitted from their saws will notice that the width of the chip is approximately the same distance between the outer edges of one side's cutter teeth to the other side's outer edge. This is because both sides work in tandem with each other to sever the chip completely. Damaged or dull teeth that need sharpening will show an obvious shiny surface along the top front edge of the chain. The first step then in the sharpening process is to realize that the tooth will need to be filed until the shiny area is removed.
If you come across cutter teeth that have suffered major damage you may have to use a flat file to remove the shiny area, then follow up with a round file and gauge for finishing off.