For homesteaders and property owners with woodlots, the chainsaw is, without doubt, the most used, coveted, debated, feared, cussed, and crucial piece of power equipment in the shed, barn, or truck. And it’s no surprise why: A well-maintained chainsaw will keep you warm during winter, allow you to create your own affordable fence posts and lumber, empower you to respond to storm-downed limbs and trees, and enable a woodlot management plan. For the most efficient, economical, and safe chainsaw experience, remember these rules: Always size and style the chainsaw’s bar to the job, and inspect, maintain, and document your bar, sprocket, and chain before and after each use.
Size Your Saw’s Bar and Chain to the Job
Proper use is one of the most efficient tool maintenance techniques, and knowing what you’ll cut is the first step in determining the best chainsaw for you, and that means knowing the range of trunk diameters and the most common tree species you’re likely to cut. If your use is varied and unpredictable, like mine, consider multiple saws and chains. For example, in an experienced user’s two-saw setup, a short saw, such as a 12- or 14-inch model, is used for limbing, pruning, and felling small trees, while a long saw, with a bar length over 22 inches, is reserved for felling large trees and bucking logs.
Many manufacturers and professionals agree on a bar-to-tree ratio of 1-to-2, which means that an 18-inch bar can cut trunks up to 36 inches in diameter without damaging the chain, bar, or motor. However, if you consistently cut trunks at the high end of your bar-to-tree ratio, consider a larger bar and engine — your chainsaw won’t last as long if you constantly use it at its maximum workload.
While your target bar length should dictate your minimum engine size, don’t oversize your engine for “reserve power.” Fatigue from fighting too large a saw is fairly common and quite dangerous for you and those working around you, so choose the right machine for the job at hand, and let it do the work for you. Finally, after you have all the information about what you need to accomplish, talk with a reputable dealer of high-quality chainsaws. Find the right tool size for the task, and make sure it suits your body, your personal fitness, and your strength.
Sharp Chains Make Clean Cuts
A good sawyer knows the ins and outs of cutting chains. In addition to bar length, the pitch and gauge are the fundamental measurements that affect cutting-chain performance. A cutting chain’s pitch represents the space between its drive links, measured either as fractions of an inch, such as a 1⁄4-inch pitch, or in thousandths of an inch, such as a 0.404-inch pitch. Similarly, a cutting chain’s gauge, or the width of its drive links, corresponds to the width of the sprocket’s teeth in a chainsaw’s drive mechanism, with sizing in thousandths of an inch. Compatibility is the primary concern with pitch and gauge. Always record and store every chain’s pitch and every sprocket’s gauge to guarantee compatibility — your drive sprocket and bar will thank you.
Tooth shape is another variable to consider when determining the best chainsaw for your needs. Consumer saws come with round-toothed chains, which are less prone to kickback and vibration. Professionals, however, make use of the square-tooth, or chisel, chain. The two differ in the way that they remove wood fibers after severing the grain. Whereas rounded teeth scoop wood out of a cut, like a gouge, a square tooth chips the wood away like a chisel, removing the wood fiber faster. People argue about which tooth profile is better, but the point is moot: Each serves a specific purpose, and, when sharp, both do their jobs accordingly. Round-toothed chains are better suited for limbing, brush-clearing, stumping, and cutting through hardwoods and frozen or dirt- and mud-covered wood. Additionally, because they require more power from the engine on big cuts, round-toothed chains are best for shorter bars. Square-toothed chains, on the other hand, perform best on a long bar (24 inches and up) and when used for felling clean softwoods that aren’t frozen.
Finally, cutting teeth come in three different configurations: full-complement, half-skip, and full-skip. A full-complement chain has the maximum number of teeth possible. A half-skip chain adds an extra spacer (a non-toothed link) between pairs of cutting teeth, and a full-skip chain adds two spacers, resulting in a third of the cutting teeth found in a full-complement chain. Because full-complement chains have so many teeth, they cut smoothly and cleanly, and respond predictably to user input, making them ideal for cutting debris, brush, and even small-diameter trees. A full-complement chain will also stay sharper than a half- or full-skipped chain simply because of the lightened load per tooth. On the downside, cuts from a full-complement chain are relatively slow, thanks to the close-set teeth that pull more debris out of the cut, which also means that there’s a heavier strain on the engine.
On the other end of the spectrum, a full-skip chain is overkill for a casual chainsaw user. The full-skip is for big cuts. With fewer teeth, there’s less drag when embedded in a tree, so the engine runs smooth and fast. However, reducing the number of teeth makes cutting smaller diameter limbs or branches less stable, thereby increasing the risk of kickback and snagging. Additionally, with fewer teeth to bear the cutting load, full-skip chains need to be sharpened more frequently.
For most homesteaders and woodlot managers, I recommend a half-skip chain installed on a longer bar. This setup will make a rougher cut than a full-complement chain, but it will cut quickly and easily through dense woods, much like a full-skip, and will be a boon if you have to tackle a large-diameter trunk that tops out your bar’s length-to-diameter ratio. Believe it or not, half-skip chains aren’t a popular replacement choice. This is likely due to owners who simply replace full-complement chains and professionals who prefer full-skip, when neither wants to experiment with the middle choice.
Basic Tooth Maintenance
For your own safety and the longevity of your chain, look out for sawdust-sized waste instead of chips, excessive burning smells, and the feeling that your chain is riding a cut and bucking, instead of deepening it with ease — all telltale signs of dull saw teeth. Plenty of tools exist to sharpen a chain at home, but you really only need a file, good lighting, and time. Before sharpening, secure the chain with a vice, or cut a 2- or 3-inch kerf in a felled tree and seat the middle part of the bar there. Pay attention to two angles when sharpening: the side-plate cutting angle and the top-plate angle, often called the undercut. To maintain a proper undercut (for smoother cuts), the top of a round file needs to protrude over the top plate just slightly (about 1⁄8-inch). While sharpening, maintain the cutting angle with one hand while maintaining the undercut with the other. The sharpening action itself isn’t too difficult — after a couple of firm strokes away from you, the tooth should be done. While sharpening, remember that, like many saws, a chainsaw’s cutting teeth alternate from left to right to keep the cut straight. Cutting teeth need not be a perfectly uniform height, so resist the temptation to take them all down to match the lowest one. If you’re aiming for more consistency, however, use a file guide.
You’ll modify your sharpening technique slightly based on tooth shape. Round teeth take a question-mark shape because of the rounded side plates, and most chains specify what size of round file to use. Looking at the top of the chain, you’ll notice that the cutting portion of the tooth is formed at a 35-degree angle, and your goal while sharpening should be to maintain this angle, or to reclaim it if it’s been offset for some reason. Square chains are shaped like the number 7 and require a bit more patience. Three-cornered and double-beveled files are best suited for square-tooth chains. Align the corner of your file with the corner of the cutter. Proper tool positioning squares the top plate angle, undercut, and corner. Think of the cutter tooth as your jig — if the file moves within the jig, even slightly, all your angles will be off. For this reason, it’s important to work slowly and decisively when sharpening a square cutter. Clean the gullets, too, by filing them up to the corner.
Shark-fin-shaped rakers, or depth gauges, determine how much wood enters the gullet, and because the top plate is angled, the cutter height will decrease with each sharpening. You’ll have to adjust the raker height to keep your saw cutting properly. While this is something that you can do freehand, use raker-specific gauges and filing tools for best results. Choose lower raker heights for softwoods and limbing (0.035 to 0.050 inches), and high rakers for hardwoods and large cuts (0.020 to 0.030 inches).
During your maintenance routine, you’ll sometimes need to replace broken or damaged teeth or kinked sections of chain, which will require only a few tools and some spare links and teeth. After first filing off the rounded head, knock the rivet through with a narrow punch, or place in a chain break to back the pin out of its hole. Completely remove the pin; install the new tooth, section, driver, or link with the correct side facing up; and finish with a new pin. If you use a hammer, you’ll need to form a rounded rivet head with a ball peen. If the chain is stiff, the rivet will be too tight, but it will loosen with use.
Bars and Sprockets
Guide bars will last a long time, often outlasting both the chain and motor. For even more adaptability, consider adding multiple bar lengths to your kit. As a general rule, one engine can reasonably power three different bar lengths: the stock size, one size shorter, and one size longer. Putting too much strain on a saw’s engine will absolutely ruin it. Full-skip chains are the exception because their reduced drag allows for longer bars. Adding bars and sprockets is a cheap, simple alternative to buying three different saws.
Like pitch and gauge, the drive sprocket must also match the new bar and chain, and both must be maintained. By regularly inspecting and lubricating the drive and bar sprockets with bar lubricant, and by occasionally flipping the bar, you can dramatically prolong bar life. Keeping written logs of pitch, gauge, and sprocket size as they correspond to bar length becomes crucial at this point in saw ownership.
Maintain Your Chainsaw for Hard Work
Bent bars, dull or chipped teeth, and loose chains can all result in tragic accidents, so it’s of the utmost importance that, at the very least, you swap out dull chains if you’re not able to sharpen them. It’s easy to put the saw up on a shelf when it’s not in use and not think about it until you need it again (which some users are likely to do for years), so give it a careful look each time you get it down.
Aside from general maintenance practices, engine maintenance isn’t a task that’s suited to the average do-it-yourselfer. I encourage friends and colleagues to have their equipment professionally serviced if it isn’t running correctly. Often, all we need to get the most out of a chainsaw is more chain options, a better understanding of how to match a bar to an engine, or new skills — not necessarily a new saw.
Joseph Love has felled trees in Kentucky, North Carolina, and Tennessee to clean up storm damage, build hiking trails, or clear lots for personal use.