How To Sharpen A Chain Saw
At discount chain saws we understand the importance of a well sharpened chain saw. Whether running a farm operation or just around the family home, knowing how to sharpen a chain saw reduces the time and effort required to clear out that field or trim up the backyard.
There are three steps to sharpening a chainsaw:
Shaping the cutters(teeth);
Adjusting the depth gauges(determines the depth of each cut);
Adjusting chain tension;
Sharpening a chain saw requires a few basic tools and just a little bit of know-how.
You will need a filing guide, a round file, and a depth gauge guide.
A filing guide attaches to the chain bar and directs the path of the round file as it moves across the cutters. You'll want to make sure your round file is good and sharp and is correctly sized for the chain. If you have a new chain saw the owner's guide will list the required diameter of the file. New chain saws come with saw chain guides that list recommendations. You will also use your filing guide with a flat file for the depth gauge guides.
Depth gauge guides should be filed down to maintain accuracy as the cutters(teeth) wear down. This should be done about every third or fourth sharpening.
Beginners should use their new chain saw as practice. The angle of the cutters and the depth gauge height will still be pretty close to perfect when the saw is due for its first sharpening, making the process a little easier for the beginner while providing experience for the time when sharpening will require more effort and knowledge.
Prior to sharpening your saw, make sure it is clean and free of chipped or overworn teeth. As a rule of thumb the flat surface at the top of the teeth should be at least 1/4 inch in length. Any shorter and you run the risk of a broken chain while operating your saw.
Place the chain saw on a stable surface or clamp the bar in a table vise to allow the chain to move easily around the bar. Locate the leading cutter. This will be the shortest cutter(tooth) on the chain. If all of the cutters seem to be the same length, just start anywhere. Your main concern is to file each cutter the same length, so that they each cut away the same amount of wood. As a reference point mark the first tooth you cut with a dab of whiteout or an indelible marker.
Carefully, put the file in the notch on the front of the cutter. This is the angled "tooth" on the front of the flat surface of the chain link. The curve of the file should fit the curve of the face of the cutting tip, and the top of the file should be nearly flush with the top of the tooth.
While holding the file make sure you maintain the same angle that the cutter is filed to begin with. More than likely the angle will be around 25 degrees but, it is important to keep the angle the same. Using a moderate twisting motion to remove metal chips(filings) slide the file across the face of the cutter. You will then push your file from the short side of the angle toward the long point. This should leave a smoother cutting surface.
File each tooth with the same angle from one side of the chain around the loop. As you move around the chain, you will want to spin it so the teeth you are filing are on the flat top side of your bar.
Reverse sides of the saw and go around the unfiled teeth angled in the opposite direction. Be aware of the length of each flat top of the cutter. There are some manufacturers who say you should use calipers for the measurement but if you have a good enough eye you shouldn't have any problem.
Check the depth gauge clearance. These are the curved hookshaped links between the cutters. They should clear each cutting edge about one tenth of an inch lower than the cutter. This determines the amount of chip that the cutter removes on each pass through the wood. A special tool to protect the adjacent teeth as you file is laid on top of the blade and is available from chainsaw dealers or hardware stores. File any gauges that are too high with a flat mill bastard file.
Once you've completed these steps and are satisfied with the sharpness of your saw, oil it up, check the chain tension and you're ready to trim or take down some wood.
A couple of reminders: Buy the correct size file for your saw. The owners manual will provide you with the correct measurements. Make sure to use a
file guide to maintain the correct angle of your file stroke when filing your blade. The pros say you should take your saw to a chain saw shop after hand sharpening five times. They will use a professional chain saw sharpener and get you going in no time. Do this to correct any variations in tooth pitch that occurred during filing. Don't forget to wear safety glasses and gloves during the sharpening process.