Chainsaws – Useful and Dangerous Tools
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Chainsaws – useful and dangerous tools Proper training is required to use a chainsaw safely. by Peter Kolb Extension Forestry Specialist, Montana State University Anyone who has worked with or around trees and forests has MSU PETER KOLB, BY PROVIDED PHOTO Peter Kolb using a chainsaw in a very probably used, or at least been tempted to use, a power saw, dangerous setting also known as a “chainsaw.” The convenience of being able to cut through a tree trunk or branch in several seconds versus tooth is a razor sharp curved chisel that is engineered to grab spending a strenuous hour with a handsaw makes a chainsaw into wood (or other material) and pull itself into the wood, an incredibly useful tool. However, the fact that this tool is chipping out a chunk. This is designed so the saw will pull basically a motorcycle engine with a cutting blade attached itself into and through wood rather than fatiguing the user who otherwise would have to push the bar through the wood. that can be dangerous without proper training, should make a OF CLIPART.COM COURTESY PHOTO person think about a purchase and what training is needed to When the chain is moving at full throttle, teeth move through use it safely. wood at the rate of about 10 teeth per inch of wood per second, each gouging out somewhere between ¹/8 to ¼ inch Chainsaws come in a wide variety of sizes and power options, of wood. That translates to about ½ inch of flesh or bone per ranging from very light electric powered saws to ten pound tooth, or about four inches of leg per second. machines with yard-long cutting bars, designed to efficiently cut through 3- to 5-foot diameter logs. New chainsaws are Another hazard, called kickback, happens when the tip of a expensive, ranging from several hundred to over one thousand running but poorly held saw touches a hard surface. The force dollars depending on their power, construction, and features. of the spinning chain flips the saw backwards toward a users face or shoulder, potentially inflicting injury or death. Even In general, the majority of chainsaw accidents happen to with a proper grip on the saw, a user’s legs and feet always casual users who purchase a smaller saw for trimming trees, remain within easy range of the sawblade and account for cutting firewood, or clearing access roads. This may be about 40 percent of chainsaw injuries. because the smallest electric power saw has more torque than a world-class weightlifter can control when the saw is Knowledge of such accidents (more than 28,000 in 1999 PHOTO GRAPHIC COURTESY OF PETER KOLB GRAPHIC COURTESY PHOTO not used properly. Modern saws have many safety features across the U.S. according to the Consumer Products Safety designed to reduce injury to the user (Figure 1), but the Commission) prompted chainsaw engineers to add safety very purpose of the saw – to cut through trees – makes it features that reduce the chances of terrible accidents. The impossible to protect the user from the most dangerous part, first is the chain-brake and handguard on top of the saw. This the chain. feature protects the top hand from debris or slipping off the grip onto the cutting bar, and more importantly it is a lever- A chainsaw operates much like a motorcycle. The motor in the activated brake that stops the chain from rotating should the main housing turns a sprocket at the base of the protruding saw kick back. Another innovative feature is the anti-kickback blade (called a bar) that pulls a chain with sharpened teeth chain configuration that has an extra non-sharp tooth built into around the outside of the bar along a special groove. Each the chain between each cutting tooth that deflects the rotating 8 | big sky small acres chain's power in a kickback situation. Although this feature used or the work turned over to a professional. When a saw is may slightly impact the chain's cutting efficiency (depending too heavy, the user tends to lunge the saw onto the object they on the saw and wood being cut), it is a highly recommended wish to saw rather than move the saw in an easy, controlled feature for the novice or occasional user, which the majority manner. Breaks should be taken to avoid muscle fatigue and to of users are. Even for experienced users, being in tune with properly maintain the saw. a saw requires daily use and constant physical conditioning. One of the biggest safety issues is a chain that is too loose, Thus, taking a two-month break after using a saw puts anyone which is determined when the saw is off. The ideal tension right back in the novice category when they pull it out and allows for a dime or penny to barely fit under the chain when start it up. it is stretched away from the bar. All chains loosen with use There are additional safety features that most modern saws and should be periodically tensioned. It’s important for a user have. These include anti-vibration shock absorbers in the to learn how to do this before using a saw. A loose chain or PHOTO PROVIDED BY PETER KOLB, MSU PETER KOLB, BY PROVIDED PHOTO handles to reduce fatigue and nerve damage to hands; a lack of chain lubricant will cause a chain to pop off the bar or chain-break under the saw to catch a broken chain before it to break. wraps around your lower hand; a throttle brake that prevents As with any tool, users should practice using the chainsaw the saw from powering up unless you have a firm grip on in a controlled setting before using the saw in rough terrain the back handle and throttle; exhaust that blows wood chips or more difficult circumstances. Stretching toward the object away from the face; a spark arrestor that prevents a saw to saw decreases control, thus it is best to step closer and from throwing sparks and starting fires; and a tip guard on the be deliberate about where to cut. The final two tips are: 1) saw bar that prevents kickbacks, though this feature greatly PHOTO COURTESY OF CLIPART.COM COURTESY PHOTO make certain anyone helping stays at least four feet from the inhibits sawing ability and is not too common anymore. furthest cutting reach the saw operator has, preferably 10 feet Additional external safety features that the user must have are away in case the operator trips or falls, and 2) be wary of used 1) eye protection, 2) hearing protection, 3) saw chaps that pro- saws that do not have modern safety features. Older saws tect the legs, ankles, and groin/femoral artery, and 4) a hard hat may be considerably cheaper to buy, but many lack proper to protect the head and face from falling debris, kickbacks, and safety features and may have broken parts, metal fatigue, or flying debris. Helpful additional features are slip-resistant gloves worn out parts that make them unsafe. and hard leather or steel-tipped boots with gripping soles. More information about proper chainsaw use can be found Using a chainsaw is hard, physical work and the user should online by viewing YouTube videos developed by major brand have the necessary strength and coordination to use it. If it is manufacturers of chainsaws or by visiting the MSU Extension an effort to lift the saw and hold it in a cutting position for more Forestry website under chainsaw safety awareness at www. than 5-10 minutes at a time, either a lighter saw should be msuextension.org/forestry/videoresources.html. PHOTO GRAPHIC COURTESY OF PETER KOLB GRAPHIC COURTESY PHOTO FIGURE 1. Chainsaw Safety Features Fall 2016 | 9.