Chain Saw Safe Work Practices

Kickback, Pushback, Pull-in

Reactive forces may occur any time the chain is rotating. They may result in loss of control of the chain saw, which may, in turn, result in serious injury or death. There are three common reactive forces at work when using a chain saw.

• Kickback may occur when the moving saw chain near the upper quadrant of the bar nose contacts a solid object, such as a nail, or becomes pinched by the tree being cut. The result is a rotational force in the direction opposite to the chain movement, meaning that the bar may be flung upward and backward towards the operator. Many factors influence the kickback reaction, including chain speed, the speed at which the bar and chain contact the object, the angle of the contact, and the condition of the chain.
• Pushback occurs when the chain on the top of the bar is suddenly stopped when it becomes pinched by the tree, caught, or encounters a foreign object in the wood. The resulting force drives the saw straight back toward the operator and may cause loss of saw control. Pushback typically occurs when the top of the bar is used for cutting.
• Pull-in occurs when the chain on the bottom of the bar is suddenly stopped when it becomes pinched, caught, or encounters a foreign object in the wood. The reaction of the chain pulls the saw forward and may cause the operator to fall onto the chain saw or lose control of the saw. Pull-in frequently occurs when the bumper spike of the saw is not held securely against the tree or limb, and when the chain is not rotating at full speed before it contacts the wood.

Holding the chain saw

How you hold the chain saw is very important - if you are in the "line of fire" of the chain, you are in danger. If you're holding the chain saw (during operation) so that you're looking down the chain, it's about the same thing as looking down the barrel of a loaded shotgun. 

• Your body should be positioned to the left side of the chain saw at all times during operation. 
• Your right hand should be on the throttle, and your left hand should be holding the guide bar. Unfortunately, there is no such thing as a left-handed chain saw. Left-handed persons should hold the chain saw in the same manner as a right-handed person would hold it. 
• Your body should be in such a position that you have control over your balance.
• Avoid leaning over the chain saw when operating.
• Avoid holding the chain saw above your shoulders when operating.
• Do not operate a chain saw from a ladder. 
• Make sure you have a good, solid footing at all times. If you slip or trip, you will most likely fall onto the chain saw. Avoid muddy areas and other slippery surfaces. If necessary, remove debris from the area where you will be working.

Carrying the chain saw

The saw should be held to your side. The chain bar should be pointed behind you and the chain brake should be engaged. Do not hold it in front and engage the throttle while carrying.

Starting the chain saw

Before starting the chain saw, the chain brake should always be engaged. The area should be free of debris, and the starter grip should be pulled with the right hand. There are two approved methods for starting the chain saw. The preferred method is while the chain saw is on the ground. This provides maximum control and minimal opportunity for accidents. The second method is where the chain saw is otherwise supported (i.e. hold the rear handle of the chain saw tightly between your legs just above the knees). "Drop starting" a chain saw is dangerous and should never be done.

Always follow the manufacturer's instructions for proper fueling. Chain saws should be fueled in an area that is at least 10 feet away from any open flame or ignition source, and as always, never fuel a chain saw while it is running.

One important factor is the gasoline (fuel) being used. The octane is not as important as the freshness of the gasoline. Fresh gasoline (mixed to the recommended gas to oil ratio of 50:1) cools the two-cycle engine more effectively than old gasoline. Gasoline goes "bad" in about 90 days, much the same as a bottle of soft drink loses its fizz after a few days. 

• Gas stabilizers or boosters are not necessary for two-cycle engines.
• Once a plastic gas can begins to fade in color, the polymer is dissolving into gasoline, which can affect the engine.

Carburetor icing can occur when the chain saw is operated in temperatures below 40 degrees Farenheit. Erratic engine performance is a typical indication that the carburetor has frozen, such as "choking" when in use (because it's frozen) and operating fine when it is checked later (because it has thawed).

Many chain saw brands have a gate/plate/plug with a snowflake and sun on it that can be reversed in cold weather to recycle exhaust (warm) air back through the system to prevent freezing or icing. In warmer weather, the gate/plate/ should be turned over to help cool the engine, or the plug pulled/pushed as indicated. Often this device is found near the air filter and the cover must be removed to access it. Always follow the manufacturer's instructions for proper use and maintenance.

Wedges

Metal splitter wedges are for splitting firewood with an axe - not for assisting with tree felling. If the chain saw hits the metal wedge, it could result in a reactive force as well as damage to the saw. Always use a plastic felling wedge with the chain saw.

Techniques

Always consult your operator's manual for proper tree felling techniques. Descriptions and illustrations are often provided which can help you decide the proper method and technique for what you will be cutting. There are two situations that pose a significant risk and are worth mentioning here.

• "Spring poles" are present when a tree is bent over like a catapult and will spring loose if not properly cut. Make several small cuts (not completely through the tree) in the arch of the tree. This should ease the tension and permit you to safely cut the tree. 
• "Widow-makers" refers to logs and fallen limbs that are stuck up in a tree that you're about to cut down. They are unpredictable, uncontrollable, and dangerous. Whenever possible, remove the limbs before cutting the tree/limb to minimize potential accidents.

Have a plan

It is important to have a plan before you begin cutting. Which way do you anticipate the tree falling and what will be your primary and secondary escape routes - typically 45 degrees to either side of the tree. Check the area for objects that may be affected by the falling tree - overhead power lines, vehicles parked nearby, or houses or other structures in the area. Make an educated guess as to how far the tree will fall and ensure the area is clear.