sharpening a chain saw
Can someone educate me as to the proper way to sharpen a chain saw? ( Both in the field and in the garage.) Someone said Dremel makes a specific bit for this, but I have not seen one. I have a file, but I know there have to be some tricks/tips on its use.
Dremel makes a special bit, make sure you get the right diameter for the specific chain your using. They also sell a cheaper than dremel tool made just for sharpening chains. The power tool is easy to use. Just mark one of the teeth on the chain with a marker so you know when you've completed the loop of teeth. The tool has an angle mark to guide you on the proper angle and just make a pass up tight in the hook of the teeth.
Be sure to wear safety goggles and gloves.
To use the file, same deal, they have a handy metal guide that attaches to the file and shows you the angle, then make a few passes up into the hook of the tooth. Make sure you use the right diameter file for your chain.
I prefer to bring two or three chains with me rather than hand filing.
The person trying to describe an elephant to the blind man comes to mind here...but, to begin with, sharpening a chain saw by hand takes time to learn and perfect.
I suggest that you try and maintain the saw on a flat surface with the bar level and as straight (as if you were cutting straight down) as possible. This way, as you switch sides to sharpen the other set of teeth, you have some means of orientation between the two sides. Always push the file through from the inside of the tooth to the outside of the tooth (where the point is.)
There are two angles to be aware of that you will need to keep your file held to: 30 degrees from tooth point back to inside of tooth and 10 degrees below horizontal, so that not only are you angled back 30 degrees from straight across the front of the tooth, but you are coming up from 10 degrees below horizontal at the same time.
After you have sharpened a tooth, remove the file to see if you have actually exposed new steel across the new face of the tooth.
Next, look from the side (preferably the outside) at the tooth and you should see a bit of "hook" on the point of the tooth. If there is no hook, but rather a straight-up leading edge, you will need to push the file down into the tooth harder as you file. The bottom side of your file should be scarring the top edge of the chain's side-strap that connects each cutter to the next.
Also of critical importance are the rakers, which protrude up directly in front of the cutter. They guage the depth of the cut and need to be filed down as the tooth is filed down and becomes shorter and shorter. Use a guage to do this. The guage should have come with the saw, but if not, they are only a few bucks at the saw shop or hardware store.
A warning: file the rakers down too much and your saw will be grabby and bog down (too agressive.) Not filing them down enough will not allow the teeth to cut like they should if sharp. You should be getting nice long chips of wood from a sharp saw; powdery sawdust from a dull saw Use a guage and wear gloves.
Keeping a saw sharp doing trail work will be a real chore. If possible, do all your clean cutting first while the saw is sharp. Then do your dirty work: roots, stumps, etc.
Good luck! You are really going to need it, but don't despair, you will get better every time you sharpen it.
White Clouds - Heart of Idaho
When it comes to doing it right, there's no substitute for a clamp style file guide. It's a little cumbersome at first, but taking the time to learn how to use it will give you a properly sharpened chain every time.
It will also get you used to how it should feel when you're sharpening the chain correctly. After about 2 years of using the guide, I feel comfortable doing it freehand now.
If you don't sharpen chains very often or you have money but very little time, another alternative is to have the chain professionally sharpened at a chainsaw shop. They usually charge about a buck a foot.
thanks for the tips....I had thought about just using a new chain in the field. I watched one of the National Park Service maintenance guys put on a new chain the other day....the first thing he did was run the saw wide open for 2 or 3 minutes...sure enough, the chain stretched some so he tightened it up and was ready to go.
New saw chains, with a factory edge, are not sharp, or at least they didn't used to be. (It's been a while since I bought any new chain.) They do have an edge, but it is a rough and grossly sharpened edge. You can easily improve on the chain's sharpness by lightly passing a file over the teeth a few times.
In fact, if you do have a new chain, use it as a guide to get a feel for the right position of the file on properly sharpened teeth. And by properly sharpened, I mean the two angles I spoke of earlier and not, unfortuneately, sharp edges. The one advantage of the new chain is that each tooth is exactly a duplicate of every other tooth: something that will be harder and harder to emmulate as you begin to add your own sharpening efforts to the new chain.
Remember, when you look straight down on the new chain, you are seeing that 30 degree angle on each tooth. That is what you want to see after you are done filing. When those angles begin to wander and become flat or too angled, you may find that it will become harder and harder to make a straight cut.
As for putting on a new chain, reving the saw isn't necessary to break in a new chain. Sure it will stretch some, but not nearly as much as it will once you start cutting with it. If your oiler is working, keep your chain tight enough that when you lift the straight, extended, level bar and powerhead by the chain at the mid-point of the bar, the chain will pull up out of the guide groove of the bar some and still run smoothly around the bar. Too tight is usually better than too loose if your saw's oiler is working right.
One last note: I never used to rev my saws if they weren't in the wood. For tuning your high idle, I recommend: a sharp chain, guaged rakers, and making any idle adjustments while the saw is warm and working, so find a big log and start a cut, then put your screw driver to the high idle screw and with throttle wide open, make your adjustments so that the saw peaks while it is working. Use it's sound to identify the highest rpm. Either set it there or back the high idle out just a bit to bring the mixture up a little (better than too lean) and drop the rpm's some. If you have a spark arrester and can see it, note it's color. A tuned saw should be cocoa color, a lean saw will be whiter and a too rich mixture will be dark chocolate. Emmm, yummy.
Last edited by mudflap; 04-12-2008 at 09:56 AM.
White Clouds - Heart of Idaho