Chain Saw Safety Wayne Fisher, Extension Safety Specialist, University of Idaho

Any chain saw can be as savage as a shark to those who mis­ handle it. If you want to get the best out of your chain saw without being bitten, always treat it with real respect. If you are a beginner or an occasional user, do not try to act like a full-time professional who can safely do things with a chain saw which would land the novice in a hospital. Felling, limbing, bucking and trimming trees can all be hazardous tasks if not done with due care.

Safety Preparation Safety begins before actual work begins. Protect eyes, head, ears, feet and hands with: - hard hat or bump cap - safety glasses or goggles--flying wood chips can injure eyes - trim-fitting trousers, shirts and jackets to reduce chance of clothing tangling in saw - avoid scarves, long skirts--tie back long hair - light non-slip gloves to protect hands from abrasions and wood cuts - nylon protective leg chaps - footwear with good grip to prevent falls--boots will protect lower legs; steel toe safety boots will protect toes - protective devices against the 1 00-decibel or higher saw noise level. Good ear muffs or comfortable molded ear plugs will allow a full work day without ear damage and fatigue. If ears ring for an extended time after sawing, hearing damage may have occurred. The unprotected user should limit his oper­ ating time to one hour per day maximum. - a chain saw sized to fit the task.

Start chain saw engine by setting saw on firm ground with chain out of gear and free of obstacles, placing right foot in loop of rear NON-SLIP SHOES handle, pressing left hand down on upper handle and pulling a COVER (S~ ~ ANDGa starter rope straight up witli right hand. Over-oiling of chain increases accumulation of flammable SAFETY - . SAFETY ~ (J lJ material on the saw. Proper adjustment of chain oiler will help " HARD" HAT HEARING PROTECTION DEVICES GOGGLES prolong chain life and insure good performance. When automatic Protective equipment is mandatory for operator safety. chain oiler over-oils it may run dry before the next refueling stop. Main Hazards Saw-related backup equipment is essential. Shovels and fire Chain saw accidents stem from both direct saw contacts and extinguishers are required by law in some forests. A three-gallon, related non-contact situations. A Swedish study shows only 30% pressure-type garden sprayer with a special medium spray pattern of tree felling injuries are due to direct saw contact; 40% are non­ tip malaxe, sledge and wedges. A saw case or protective chain between sharp edges other than the tool, etc. scabbard reduces damage to sharp chain during transport. Fuel Two of every three accidents to casual operators and helpers and chain oil containers should be sturdy and spill-proof. or bystanders are caused by inadvertent contact with the moving chain according to a recent Consumer Product Safety survey. Study Owner's Manual In these accidents, the operator makes a careless move such as The owner's manual should be understood before the saw is reaching across or holding work near the moving saw, or loses used. Ask your dealer to answer questions about any details you saw control allowing it to come in contact with body. Loss of do not understand. Essential maintenance tools include sharpen­ balance due to loss of footing and subsequent loss of saw control ing file for dressing the chain, and screwdriver and wrench for accounts for one of every six accidents. Hazard awareness can making needed throttle and clutch adjustments. Throttle adjust­ sharply reduce the incidence of injury. ment should be such that engine operates at recommended speed Kickback is a major chain saw hazard. In kickback, the upper during sawing and chain clutch disengages immediately on re­ chain "grabs" in the wood or an obstruction and forces the saw lease of throttle trigger. Chain tension should be adjusted to backward, causing operator to either lose control of saw or lose insure quick, smooth cutting--too loose a chain will derail; too tight his balance, bringing saw into contact with his body. Loss of a chain will bind. All chains stretch with use. Most of this stretch balance often causes him to reach into the running saw chain as will occur during first half hour of operation. he grabs to steady himself.

Extension Bulletin 0727 Cooperative Extension Washington State University Pullman

Issued by Washington State University Cooperative Extension, J. 0. Young, Director, and the U.S. Department of Agriculture in fur­ therance of the Acts of May 8 and June 30, 1914. Cooperative Extension programs and employment are available to all without discrimination. Published June 1980. A chain can lock or a saw can kick back for many reasons. power supply line will help prevent fatal shocks. The soil should Watch for these kickback causes: be relatively dry and damp foliage should be avoided. Lay cord out • Abrupt change in wood characteristics, i.e., green to dead in a manner which will not interfere with work--it should not be • Running saw too slowly underfoot to cause tripping, or placed where it could be cut by e Build-up of damp sawdust saw. Ample cord length will allow operator to keep cord at his • Twig caught in chain and jamming against work right and strung behind him. Check to be sure saw switch is in off e Branch or obstruction on opposite side position before completing electrical connection. Unplug power e Twisting of saw--cutters grabbing wood before making adjustments and when saw is not in use. e Sawing with point of guide bar (nose sawing) Hold saw firmly with both hands in proper position when e Closing kerf. cutting. Make sure thumbs and fingers completely encircle saw Kickback is almost certain under certain conditions. Cutting handle. Always keep elbows and knees flexed for maximum con­ with upper side of bar may be convenient but is dangerous, especi­ trol. Operate saw to side of body so it will not swing into body if it ally with larger, more powerful saws. If chain locks when saw kicks back, comes out or through unexpectedly. Never shift hand is used in this position, sudden kickback will throw saw backward positions or cross arms for easing strain or better reach. and perhaps injure operator. Always have a firm grip on saw and Cut with lower side of saw as much as possible. This is safest, keep body well balanced and in position such that loss of control least tiring position. Keep bumper or work teeth against wood will not mean disaster. when cutting with lower side. Having saw blade fully into wood allows for better control. Keep guide bar in middle of cut (kerf) so cutters on opposite side will not hang up. Guide saw into wood. General Safety Procedures Do not twist guide bar. Keep chain properly sharpened--a wide Fire hazards with chain saws are numerous. The chain saw kerf, fine sawdust instead of chips and a need for force indicates operator should check the fire index before entering the forest. a sharpening is due. A crooked kerf may be due to sharper cutters Working conditions where fire danger is high demand extreme on one side of chain. Never allow running chain to contact ground precaution. The air-cooled engine head and muffler are hot and or metal--one such contact can dull chain more than cutting exposed. Type fuel used, frequent refueling, and spillage associ­ dozens of trees. ated with the hot engine complicate the problem. Sawdust should Many newer saws have a chain brake--a device actuated by be brushed from the motor regularly. Oily sawdust accumula­ operator's hand to apply a brake when reverse motion of saw tions can easily ignite, drop off, and start a fire. Hot exhaust sparks occurs. The brake is not effective in the horizontal position, as directed into tinder can cause ignition, as can sparks from the when felling a tree, and is not always activated if operator loses high speed steel chain striking a stone. his grip on upper hand hold. Refuel saw when it has cooled and is in a clear area to avoid spills onto leaves, needles or sawdust. Gradually release pres­ Felling Procedures sure in fuel tank before removing cap completely. Use proper Have saw in top operating condition. Never attempt to cut a funnels and spouts to prevent spills and a fuel can small enough tree with a diameter greater than the length of the chain saw for easy handling. Leave recommended expansion space in tank. blade. Be certain once felling operation is started that saw will Never smoke while refueling. Fill chain oil carefully with a dis­ function to completion. Knowing that saw is performing properly penser bottle. allows operator to focus all attention on felling procedure. Consider particular characteristics of each tree felling project. One tree may lean; another tree might be unbalanced due to uneven top growth or breakage even though trunk does not lean. Large diameter branches are good indicators of unbalance. Pre­ vailing wind direction affects tree growth and balance. Fall direc­ tion is affected by present wind conditions. The inexperienced operator should never attempt to fell trees on windy days. Clear ground around base of tree of limbs; remove under­ brush and other obstructions. Clear tinder from exhaust discharge area. Remove low, interfering branches and any loose or dead limbs before felling. These precautions provide clear vision, unrestricted movement and an unhampered escape route when tree begins to fall. Plan escape route to rear and/ or side, depending on likely direction of fall. Plan in advance what to do with saw when tree starts to go. Shut it off and drop it in a safe place, thus allowing an unhampered escape. ·

Refuel chain saw on bare ground to reduce fire hazard. Do notre­ fuel a hot saw. Never smoke when refueling. Avoid spilling fuel. If fuel is spilled, wipe off immediately. Move to clean area before starting saw. Always place saw on ground when starting.

Start saw engine in a clear, level area as close to the work area as possible. Hold steady with foot placed in rear handle bracket or as recommended. Carry idling saw into cluttered areas rather than starting under adverse conditions. Carrying a running saw is dangerous--but, if is more dangerous to start saw in unsatis­ factory locations. Plan approach path and watch footing and balance when crossing obstacles. Carry saw with muffler away from body and chain to the rear. The chain will be stopped if throttle is properly adjusted. Some saws have a chain brake to assure stopping; use this during transfer. Be aware of helpers or bystanders when transferring a saw. Electric saws require safe power transmission. Use only Plan a safe, unobstructed path of retreat before makinq felling cut. three-wire cord of proper size with three-pronged plugs and when tree begins to fall, remove saw, stop motor, set 1t on ground 'grounded, three-wire outlets. A ground fault interrupter in the and retreat rapidly at 45-degree angle from line of fall. With felling and safety plan determined, proceed as follows: A push pole is useful for directing fall of small trees. A spike - hold saw firmly with both hands pole should be used rather than a stick. Embed pole spike firmly - make cut close to base of tree, yet high enough for convenience in good wood to prevent slippage. The helper must be in position and avoiding running saw info ground to control pole when tree falls. He should push with a steady force. - cut through trees up to 8 inches thick with one cut Trying to "rock" tree might bring it over backward. The saw oper­ - on larger trees, notch (undercut) at least one-third of trunk ator and helper must both be aware of pole action once tree starts diameter on fall side of the trunk. Make lower cut of 45° notch to fall. Continue pressure until fall is underway or tree may spring first to prevent pinching or binding of chain by wedge back. - make felling or back cut on opposite side of trunk two inches above and parallel to horizontal notch. Leave wood fibers to round steel spike 3/B" x 6'~ act as a hinge, keeping tree from twisting and falling in wrong

direction or kicking back on stump hickory or ash pole 2" X 8'~ \ - keep guide bar in middle of cut (horizontal) so cutters returning == v:::~ .::;;) c::::::======- in top groove do not recut. Guide saw into tree--do not force it. Rate of feed will depend on size and type of timber being cut pipe ferrule 2 ~ 2 1/2" long_,} - remove saw from cut and shut it off before tree falls - do not cut completely thro-ugh hinge fibers as this may cause tree to fall in any direction, possibly on the retreating operator. Push pole is very simple to make and useful for directing fall of Move away from tree at a 45 degree angle through properly smaller trees. cleared retreat lane. Tree falls can also be directed by special sawing techniques such as non-parallel hinge fibers--the wider section holding felling cut firmer and directing tree. A dutchman, part of the notch block, can be replaced. This will rock tree over in chosen direction as it falls. splint cut limbing Procedures Many chain saw accidents occur during limbing (branch re­ moval from felled tree). After tree is on ground, inspect each limb before making a cut to be sure cutting limb off will not bind guide bar or cause trunk to roll. Using a lightweight saw with a short bar makes holding and maneuvering easier. The lower horse­ felling cut power also helps operator control saw in kickback situations. 2" above Limbing progresses much more rapidly when saw is sized to the horizontal task. cut of Stand at an angle to limb when sawing so if saw slips, chain notch will not strike legs. Make first cut on limb closest to base of tree and on top of trunk as it lies on ground. Saw branches so they fall away from kerf. Clear work area of slash as soon as it becomes cluttered and hazardous. Shut off saw and put in safe place with no fire hazard while clearing branches. Never hold saw with one hand and clear limbs with the other. Transferring saw with engine running presents a particular hazard. Often it is impractical to start saw at point of first cut or direction of fall --+ to stop and start saw for each different limb. The operator must move while working. He may have poorfooting and be surrounded Tree fall direction can be closely controlled with properly made by obstacles. An organized approach is helpful for safety's sake. notching and felling cuts. When felling coniferous trees during Limbs should be cut as far up as possible on top side of trunk summer months it is desirable to make splint cuts about 2 inches before removing those resting on ground. Lesser branches should deep on both sides of tree at right angles to notch and in same be removed as work progresses up trunk. Leaving small limbs p lane as felling cut to prevent splintering. can be hazardous--they impair vision, are obstacles when making cuts, and may cause kickback due to twigs lodging in blade. Use A binding saw and closing kerf indicate an error in judgment-­ extra caution cutting small diameter limbs. The slender material at first such indicat ion, remove saw. If saw cannot be removed, may catch in saw and be whipped toward operator or pull him off do not st ruggle with it. Sh ut engine off, clear area, and plan course balance. As operator works, he should saw limbs on opposite side of action using w edges to remove saw. Use only wooden, alumi­ of trunk f rom where he is standing, using trunk as a barrier be­ num or plastic wedges--steel or iron wedges may damage chain. tween him and saw. The limbs will also drop away from operator If saw is started, be alert that chain may strike wedge and hurtle rather than falling against him. If necessary to work with saw on it out forcefully enough to cause inj ury. same side of tree as operator, keep saw to side of body so it w ill If tiring occurs before sawing has progressed to a near fall, not swing into legs or head. Avoid reaching with saw. Always remove saw, shut it off and rest until able to proceed w ith confi­ maintain good footing and a balanced position. Unorthodox posi­ dence. A lso, check f uel supply before starting a cut which will tions and sawing across in front of body invite trouble. require a long running period. Cutting bottom branches resting on ground to improve work­ A well-ba lanced tree may have to be wedged, pulled or pushed ing conditions underfoot may be necessary as work progresses. in desired fall direction. Wedges are the most dependable means The tree may sag or roll as a new branch is cut. Key branches of providing positive tree fall directional control. Use two wedges supporting and stabilizing tree should be left until last. Branches rather than one to insure a forward fall of tree. Use a sledge or resting on ground should be undercut from beneath. It is difficult mallet with a face at least one third broader than wedge. Strike to judge if branch is free or resting until saw weakens limb. squarely w ith firm but not excessive blows. Careless blows may Exercise extreme care when undercutting with top of saw; a pop wedge out, swinging tree ba ckward. Using an axehead as a closing kerf signals probable kickback. Keep engine speed up--a wedge or driver is dangerous--splintering of the steel is likely to slow moving chain is more likely to lock than one cutting freely. occur and flying particles might strike the user. The likelihood of tree rolling increases as more branches are Ropes are not too practical or derJendable for directing fall removed. Removing heavy branches from top side of trunk may as they must be very long or rigged through a pulley. Progress of cause tree to shift; removal of a heavy limb may allow branches tree may start in wrong direction as rope fibers stretch. The helper below to spring up, turning the tree. Final supporting branches must have a safe position. The saw operator's safety is subject might be saved to facilitate bucking. The trunk, however, should to the helper's attentiveness. · be stable and not vulnerable to roll during bucking. An added problem when cutting firewood may be the close A. proximity of a helper who can steady the wood, perhaps "feed" it through a " horse" and clear blocks away. Both helper and oper­ ator must be familiar with chain saw techniques and hazards before attempting to work under such close conditions.

Pruning and Trimming Branch trimming from a standing tree presents added hazards. Inexperienced operators should become familiar with the chain B. saw by working on wood that is convenient to them before at­ tempting to prune or trim. Always keep firm grip on saw with both hands when trimming--never let saw "fall" through cut. Use proper height ladders. Avoid using saw above shoulder height. Be close enough to trunk to work without excessive reach­ ing. Keep saw to right of body and work around tree to right to help provide a safe position, moving ladder frequently. c. Hoist saw with a rope. Hoisting a running saw is hazardous, but is considered preferable to climbing a ladder with a running saw or starting saw while perched on a ladder. A helper may help hoist saw and steady ladder during sawing. Securing ladder to tree with a rope and wearing a safety belt are good safety prac­ tices, even at relatively low heights. Large branches should be undercut and/or notched to help direct fall. Backcut at least six inches out on limb to allow branch to break free and not hang up or peel trunk bark as it falls. Remove Bucking procedures differ, depending on support of log. (A) When main portion of branch with a convenient cut. then trim stub log is supported along entire length cut from top, avoid sawing close to trunk. earth. (B) When log is supported on one end, cut one-third of diameter from underside to avoid pinching and splintering, then Score small branches with an undercut, using care to avoid cut two-thirds diameter from top. (C) When log is supported on saw kickback. Pruning very small limbs and trimming branch both ends, cut one-third from top, then cut two-thirds from under­ ends are performed more safely with lopping shears or a small side. hand saw. The casual operator must proceed with caution when attempting to do such work with a chain saw. Bucking Procedures Bucking (cutting trunk into desired lengths) is generally less hazardous than other sawing tasks. Special hazards of bucking include unexpected log roll and kickback. Work on uphill side of log and be sure of footing. Raise and chock trunk when possible to prevent rolling. Use levers, sturdy poles or bars as much as possible; do all manual lifting with back and strain-saving tech­ niques in mind. Anticipate and avoid "caught between" hazards. Make first cuts on large trunks on freely supported sections, slant cut so log will open cut and prevent saw from binding. If there is no opportunity to divide trunk, or when it has been divided, move to upper (spike) end of trunk which is usually supported by butt end. Logs or blocks cut from spike end should fall away freely. Cut completely through diameters of eight inches or less. Larger diameters should be scored on underside by sawing upward about one-third diameter to prevent splintering, then completing cut by sawing downward. Any hint of closing kerf indicates trunk is supported at both ends rather than one. A trunk that is flat on ground should be cut from top, then rolled over and cut from opposite side until free. Use extra care to avoid getting saw into ground. To cut through a trunk supported at both ends, simply make first cut from top (overbuck) one-third of the diameter. Depth is limited by weakening of trunk which closes kerf; stop sawing from top before kerf closes and binds. The remaining wood is cut up­ Pruning and trimming of branches should be done in the sequence ward (underbuck). shown to properly direct fall and avoid peeling of trunk bark. When cutting firewood, each block cut does not need to be completed in turn. The log may be more easily steadied if several Transportation and Storage block lengths remain together until major sawing is completed. For brief transport or storage, set saw level with gas cap up. Make cuts about three-fourths the diameter for each block; the For longer periods: log will then remain rigid. When all cuts are made from one side, • drain fuel tank in safe area roll log and complete cuts. • run engine at idle until it stops • do not carry saw in passenger space of a vehicle • be sure saw cannot tip over and spill gasoline during transport • store saw out of reach of children • disconnect spark plug on gasoline models; store extension cord separately from electric models to reduce the possibility of accidentally starting • follow owner's manual for cleaning and lubrication.

Originally published by Western Regional Agricultural Engineering Ser­ Three -legged horse to support one end of log will help steady wood vice, a joint project of the western land grant universities and the U.S. for sawing and make cuts more positive and safer. Department of Agriculture, as WRAES 66.