Chain saws are 'safety-first' tools
Chain saws are, without a doubt, one of the most helpful tools in your arsenal of grounds-maintenance equipment. However, according to Larry VanDeValk, professor of agricultural engineering at the State University of New York (SUNY) (Cobleskill, N.Y.), "Giving an inexperienced, unprotected or untrained operator a chain saw is like putting a loaded gun in the hands of a child."
Making sure that all employees are properly trained in chain-saw operation is the responsibility of all grounds-maintenance contractors and superintendents. You must not take the importance of this responsibility for granted. Research studies indicate that for every non-fatal chain-saw accident, the average medical bill is $3,000 per occurrence per person.
VanDeValk suggests that a professional grounds manager can purchase all of the personal-safety equipment (PPE) needed for one employee for a cost of approximately $400.
Such PPE includes the following essential items: * Eye protection (with adequate top and side protection) * Ear protection (plugs or muffs) * Chain-saw chaps (leg protection) * Gloves (heavy-duty, non-slip for improved grip) * Helmut and full face protection * Foot protection that includes steel toe lining * Clothing that is sturdy and snug-fitting, but allows complete freedom of movement
Chain saw components Every chain saw has three basic components: 1. The power unit includes the engine, muffler, crankshaft, throttle, spark plug, piston, carburetor, air filter, chain-oil pump and primer. 2. The chain, naturally, includes the chain itself but also the individual components of the cutter parts such as hubs, rivets, tie straps, depth gauge, top and side plates, heel and toe. 3. The bar consists of the sprocket, clutch and guide bar. The sprocket and clutch are not parts of the power unit because they attach to the bar and run independently of the engine. Clutches on chain saws are centrifugal and do not engage at low or idling rpms.
The chain and bar components are wear items that require periodic replacement. You can sharpen the chain (see related article "How to: Sharpen a chain saw" on page 20), but it is a good idea to have at least one spare chain on hand. As with all of your equipment, proper maintenance and operating procedures prolong the life of all of the components of a chain saw.
Selecting a chain saw It is true that all chain saws are basically the same. They come in different sizes, various power outputs and have various optional features. However, at the heart of the matter, they all function in the same manner. According to VanDeValk, "They all have 2-stroke air-cooled engines that provide their power, and their chains cut wood. Slight differences exist in items such as chain brakes, engine ccs, direct- vs. gear-driven units, compression-release devices and anti-vibration components. Somemodels offer "solid-state" ignitions (which may replace breaker points), automatic chain oiling, carrying case, etc. Classifications of chain saws usually exist only as 'homeowner' and 'professional' models."
If your company has only occasional use for a chain saw, such as cutting trees for firewood in the fall or removal of small trees, a small saw is appropriate. If your company has jobs that require extensive use of chain saws, a larger machine is your best choice. Chain saws are sized by three categories: 1. By the length of their guide bars, which range from 12 to 30 inches or more. 2. By the displacement of their engines-from under 3 cubic inches to 7 cubic inches or more. 3. By weight-from less than 10 pounds to 20 or more.
Fuel and oil Chain-saw engines require a fuel-and-oil mix of regular gasoline and 30-SAE oil. Check your owner's manual for specific ratios and measurements. In some states, reformulated gasoline (RFG) must be used instead of regular gas. These recommendations sometimes include special oils that you can mix at a 32-1 ratio or 0.5-pint oil to 2 gallons of gasoline. Be sure you mix the oil and gasoline in a can, not in the chain saw's fuel tank.
Most manufacturers suggest 30-, 20- or 10-SAE oil to lubricate the guide bar. They also suggest thinning the oil with kerosene during cold weather. As a rule of thumb, you should make a habit of filling the chain-lubrication reservoir with oil every time you fill the gasoline tank. If you have a saw with a roller nose, you should grease it every time you sharpen the chain.
Cleaning Each time you finish using the chain saw, clean it using compressed air and a brush. If you don't have a compressed-air source, wipe the machine down with a clean cloth and use cotton swabs to clean hard-to-reach areas. You must keep the metal fins of the engine clean of sawdust and dirt to allow for proper air circulation and engine cooling. Remove the air-intake filter at least once a day (or as often as visual inspection deems necessary) for cleaning. Simply blow or tap the dirt from the filter. If it is still dirty, soak it in gasoline and shake it dry.
Engine maintenance and starting Other than cleaning the air filter, chain saw-engine maintenance consists of three basic steps: 1. Maintaining proper idling speed 2. Keeping the best-performing carburetor setting for idle and load conditions 3. Performing ignition maintenance. Hard starting typically indicates either improper fuel mix or worn spark plugs.
If your chain saw is difficult to start, first inspect the response to the choke. If there is no firing, inspect the spark plug. It the spark plug is dirty, you should either clean it or replace it. If the plug has been used for quite some time, check the gap. Refer to your owner's manual for proper gap settings. If you no longer have your manual, it is recommended that you set the gap at 0.025 inch. After 70 hours of use, the breaker points require inspection for gap widening and erosion. If you have a solid-state ignition, it may require replacement due to wear. Finally, don't forget to make sure the power switch is on.
Storage When it is time to store your chain saw for extended periods, the following measures will preserve it and enable it to start easier when you need it: * Let the engine run and use all the fuel. This includes fuel in the tank and in the carburetor. * Dampen a clean cloth with oil and wipe down the saw, leaving a light film of oil. * Store the saw in its case or place it inside of a plastic bag or box to keep dust from settling on it. * Store the chain in a shallow pool of oil, preferably in a container with a secured lid.
What it is and what it's not Sometimes it is easier to describe what something is not as opposed to what it is. In this case, a chain saw is not designed to perform light pruning of trees or shrubs, and it is not meant to cut vines or branches that are lying on the ground. Chain saws are designed to be used only when proper PPE is worn by the operator. They are dangerous tools in the hands of untrained operators or when used without PPE.
Chain saws are tools that enable you to finish felling jobs for your customers, and you must respect the potential for danger when using them inappropriately.
Saw will not start 1. No fuel or wrong mix 2. Faulty carburetor 3. Faulty spark plug 4. Faulty ignition system
Saw starts by dies 1. Vent valve in fuel cap plugged 2. Fuel filter or line plugged 3. Fuel line leaking air 4. Carburetor needle adjusted lean
Engine runs hot 1. Clogged air-cooling screen 2. Dirty cylinder fins 3. Rotor-fan intake flow obstructed 4. Air flow past fins is blocked
* Roller nose. Reduces friction and wear on the bar and chain, thus extending their life. * Reliability of the dealer. Parts, service and repair are important purchase-decision elements. * Ease of starting, handling, balance and vibration. Test several models before making your purchase. * Serviceability. Ease of maintenance, including filling gas and oil reservoirs, cleaning the air filter, adjusting the chain tension and ease of changing the spark plug.
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