The chain saw: Ubiquitous tool of tree care, indispensable for many jobs and loathed for others. Still, it’s a tool that’s simply inseparable from modern tree care. As with all tools, proper application and technique turn a possible debacle into efficient, safe work. Nowhere is this more evidenced in accident statistics than with chain saw use, as a great number of injuries and fatalities in tree work involve chain saws.
Saw manufacturers regularly research and develop new ergonomic designs and operator features to enhance operator comfort and safety. The big four safety features — inertia chain brake, throttle interlock, chain catch pin and rear hand guard — are industry-regulated and well-known. Without them present and/or functioning, a modern saw is unsafe to operate.
However, these four are just the beginning. We’ll look at four more ergonomic practices and safety features that are less commonly mentioned. Even saw operators with years of experience fail to recognize and use them. With a little bit of explanation and some practice, these additional features/techniques can help improve safety, efficiency and overall sawing performance.
Ready … aim … cut!
Years ago as a young man, my father, while teaching me to use a firearm, explained to me what a proper sight picture was. I learned that, by aligning front and rear sights on a firearm, one could consistently predict where the bullet was supposed to hit. Later in life, an earnest drill sergeant (literally and figuratively) pounded the same lesson into my head. Imagine my relief and simultaneous trepidation when I learned chain saws had sights as well!
Saw sights consist of a single line surrounding the body of the saw. These felling, or “gunning,” sights run perpendicular to the center axis of the saw, allowing a sawyer to “sight” down the body of the saw and ascertain the “gun” or intended direction of fell. When cutting a face notch, if the sawyer positions himself or herself with the tree on his or her left, facing the direction of fell, the sight allows for bar alignment.
Making the top or gunning cut first allows the sawyer to acquire proper face cut alignment. Staying in the same position, if the sawyer then flips the saw over, places the dogs next to the kerf of the top cut and begins cutting, the sight can be monitored. When it aligns to the same point as the top cut, the bottom cut is generally even on both the left and right of the face. Also, by making the top cut first, the sawyer can safely peer down the first cut to observe when to stop cutting and avoid hinge bypass.
Lastly, the sight can be used as the back cut is made. When the felling sight aligns with the same point as the two cuts forming the face notch, and the notch has a clean, even apex, then the saw bar is parallel to the hinge wood across the whole cut.
Of course, as I learned with humor when my father taught me and graphically in the Army, just because the sights are “aimed” at the tree (your target) does not mean you are guaranteed to hit it! Skill, practice, and proper cutting and lean management techniques all must converge to fell a tree accurately.
Chain saws have handles. This is not news, but even these basic, banal saw parts have cutter operation, efficiency and comfort in mind. In making the aforementioned face cuts, the top handle of the saw is designed with on-the-ground felling cuts in mind. The average forward handle of a saw has three bends. Starting at the top of the saw, bar side, a small angle forms to curve the handle over the top of the saw. This leads to a larger radius angle above the recoil. The third angle forms just as the handle bends to connect to the saw body beneath the recoil.
Modern sawyers know that, to maximize control of falling trees, a 70- to 90-degree face notch is preferred. This allows the hinge to hold until the tree is almost on the ground. As the cutter, position the tree to your left. Center your hand in the large angle on the bar above the recoil. Be sure to keep your left thumb fully wrapped around the bar when cutting. Make the top cut using the felling sights as previously described. Now flip the saw forward and center your grip in the smaller angle below the recoil. The felling site continues on the recoil cover. If these angles are used, the face cut will be between 70 and 90 degrees. If you desire to use the top of the bar for the bottom cut, the small angle above the bar will work the same.
Ready… set… start!
Chain saws cut much faster after the recoil has been pulled and the engine is running. Starting a saw is a vital skill for cutting performance and fatigue avoidance. Unless you have an easy day, you may start your saw dozens of times in a day. Just as the large angle in the front handle is designed for felling cut alignment, so too is it made for ergonomic starting.
When performing a leg-lock start, center your left hand in the large angle. Lock your wrist and reach with your right hand to seize the recoil handle — now your back, shoulders and torso are in proper alignment. A swift, strong pull will neither twist your back nor put you in an unsafe position. So often, fatigue and injury are in the details. Here is one small detail your back will enjoy!
Just a little bit more…
You know the sound. If you have run a saw for more than 25 minutes, you have heard it. That little hiccup, the engine burble that screams, “You are about to run out of gas!” I know. I used to think the same thing: That is just the saw telling you to quickly finish cutting! No! That hiccupping sound is the saw screaming for more fuel but getting only air.
Modern saws run lean by design. Fifty drops of gas to one drop of oil is lean. As the tank empties, that ratio is made even more dramatic in favor of air. Without enough two-cycle oil, the piston will not stay lubricated. Sure, the saw runs faster, but that means it’s chewing up its life expectancy at an alarming rate.
When you hear the telltale signs — or preferably before — shut the saw down and fuel up. It will start easier, last longer and perform better in the long run.