When it comes to getting up a winter’s worth of wood, the work is never done. If I’m not cutting, splitting, and stacking, I’m scoping out trees for next year or cleaning up brush left from the last. I enjoy the rhythmic push pull of a cross cut saw. Using the venerable old handsaw is great exercise, it always works and it provides good meditative time to think, but time is its Achilles heel.
Chainsaws are everything the handsaw isn’t. They are loud, obnoxious and above all very fast. Beyond cutting firewood they have endless uses around the homestead. Their lightweight, compact size and dependable power make them irreplaceable. They do, however, share common ground with their hand-powered brethren. Both must be well maintained and sharpened correctly to utilize their full potential.
Chainsaws are often thought of as brute force, wood-eating monsters. But power without finesse only leaves a mess. A closer look at the chain reveals a highly evolved precision cutting tool. In order to keep the chain in top shape it’s necessary to understand how it works.
ANATOMY OF A CHAIN
Saw chains are made up of three basic components: Drive links, tie plates and the cutters. Drive links have two functions. They mesh with the engine sprocket to propel the chain and run in the bar grooves much like a train on tracks. Tie plates connect the cutters to the drive links. The cutter link is where the magic happens. The links are staggered left and right down the length of the chain. A cutter link consists of two cutting edges, side and top, with a depth gauge in front. It sets the amount of “bite” each tooth is allowed to take and also acts as a rake to help drag shavings from the saw kerf.
Behind the depth gauge is the cutter tooth. The side edge of the tooth clears the saw kerf for the chain and bar to pass through. The top edge cuts through the wood. Each cutting edge, side and top, is sharpened with the same pass of the file.
A sharp chain should cut smooth and straight, it should feed itself into the cut. You should not have to apply pressure to the saw to make it cut. Watch your shavings; a sharp chain throws large chips of wood, a dull chain just dust. Smoke is a sure sign of a dull or bound chain. Sparks are a sure sign you have hit a rock and now have lots of filing to do.
KEEPING YOUR EDGE
To sharpen the chain, you first need some basic tools. Like most things in our modern world the market is awash with gadgets and gizmos to sharpen a saw. All of which have more moving parts than just a file. With more parts, come more problems; simple is better. Once you have used a file enough to “get a feel for it” you can sharpen fast and accurately, without set up time and complications. Save your gadget money for a pressure canner or new wheel bearings for the pickup.
You need a round file, the correct size for your chain with a good handle. The file size is matched to the chain tooth size. Consult your owner’s manual or local saw shop to find the right size. The depth gauge is lowered with a flat file. The chain tension should be set before sharpening, so toss in a bar wrench and you’re all set.
HOLD IT STILL: The first hurdle to cross when sharpening by hand is to hold the saw at the right angle. It’s impossible to hold the proper file angle if the saw is moving. If you’re in the shop, clamp the blade in a vise. In the woods you may need to get more creative. Use an axe driven in a stump to rest the saw blade on and push against. I sometimes sit cross-legged with my leg over the saw with the blade resting on a log round. However you go about it, you have to hold the saw still.
ASSUME THIS POSITION: Next you have to be in a braced position. Keep your shoulders and upper body stiff. This gives your arms a stable platform to push from with a smooth, fluid motion.
BASELINE: Now that you are all set, find the tooth with the most damage. All the teeth should be filed down equally each time you sharpen. Count the number of file strokes it takes to clean up the worst tooth. Then use the same number on all the others.
BE CONSISTENT: Look straight down on the tooth and match the file angle to the angle of the tooth. The angle the teeth are sharpened to is important. That said, most of us will never notice the difference in a few degrees. What counts is a sharp edge on both cutting edges and keeping all the teeth even.
STROKES: Holding the file with both hands makes smooth, controlled strokes. Maintain side pressure on the file into the tooth, don’t press down. Lift the file off on the return, dragging it backwards dulls the file.
Before you make any changes to the depth gauges be sure you know the correct depth for your chain. The size of the chain, power of the saw and skill of the operator all play a role in the depth you will set. Start with the manufacturer’s recommended depth. When the depth is too shallow, the saw will cut very smoothly but slowly. It will throw fine chips or shavings.
As you lower the depth gauge the saw will begin to cut more aggressively. When it is too low, the saw will no longer have the power to pull such an aggressive depth and the chain will hang up or jam.
The more aggressive your chain is, the more prone it will be to kick back. With time you will find the perfect depth that balances the power of your saw and your comfort as the operator. To check the depth, lay a straight edge across the tops of the cutter teeth, then use a feeler gauge between the straight edge and the top of the depth gauge. With a flat file lower the tops of the depth gauges as needed.
REFRESH AN EDGE
To refresh an edge, three to four file strokes should be enough. Very dull or damaged chain will require as many as it takes to cut damage back to a fresh edge. Your best bet is to keep your chain sharp and keep the blade out of the dirt. Give the chain a touch up every other tank of gas.
With practice you will be able to keep your chain sharp and in top shape. You will get more work done with less fuel, save wear and tear on the saw and on the operator.
Generate income or create your own building materials
by David Boyt / Mar 1, 2013