Chain Saws


Lightweight, less-expensive chainsaws are a common homeowner purchase. Chain saws are gasoline or electric powered, but gas powered are most common. Power output is generally considered 1-hp-per-cu.-in. displacement; however, professional models have more horsepower-per-cubic-inch displacement. At the bottom end of the power-ratings chart would be a lightweight model with as little as 1.4 cu. in. of displacement, while the professional model will run as high as 7.5 to 8 cu. in.

Home-owners rarely need more than about a 2.0 to 3.7 cu. in. model.

Chain saws are direct drive and have chain speeds from 3,000 fpm (ft. per minute) to 7,000 fpm. Advantages are lighter weight, lower cost and faster cutting.

Weights usually are quoted as the "dry" weight of the power head (with fuel and oil tanks empty) and without the bar and chain, which vary greatly by both type and length. Most homeowner needs can be satisfied with 8-to 16-lb. units. Smallest saws may offer only a single bar length as short as 10" or 12", while more expensive units offer much longer interchangeable bars ranging from 12" to 42".

Electric chain saws, especially the smaller models with 8" to 10" cutting bars, can be used for trimming and pruning. Heavy-duty extension cords are an absolute essential.

Consumers should pay attention to quality differences in chain saws. A sprocket-tip cutting bar increases cutting speed because it eliminates most of the friction around the bar tip. It also keeps the chain from dragging around the bar nose, thus eliminating bar wear, and reduces chain stretch.

Safety is an important factor in chainsaw operation. The product must be treated with great respect. Manufacturers are taking different approaches to the safety problem.

You should become familiar with the American National Standards Institute (ANSI) B175.1 safety standard for chain saws. The standard requires chain saws up to 3.8 CID (cubic inch displacement) to pass a test limiting the kickback of a saw and making at least two separate anti-kickback devices a part of each saw.

Kickback occurs when the top 90 percent of the bar tip comes into contact with an object. This may cause the bar tip to violently kick back toward the operator. The standard is aimed at reducing the potential harm to the operator.

Most manufacturers are meeting the standard by using a combination of low-kickback chain and one other device such as a tip guard, chain brake or low-kickback bar.

Chain Saw Maintenance
First rule of care and fueling of a chain saw, whether gasoline-powered or electric, is to follow recommendations of the manufacturer. But some rules are common to all power saws.
Manufacturers recommend a gas/oil mix ratio from 16:1 to 50:1, depending on the type of two-cycle lubricant used. Chain and guide bars need frequent lubrication, and many saws have a built-in oil reservoir and dispensing system. Special bar and chain oil is available which adheres to the chain components longer, providing greater protection against wear. On some models a manual override provides additional lubrication.
Chains should last a long time, but they will become dull eventually. The time to sharpen a saw is when it first begins to get dull. Sharpening kits are a good add-on suggestion. Professionals charge about the price of the kit each time they sharpen a blade.
Semiautomatic chain sharpening systems are available on some chain saws. With these, a sharpening stone may be activated against a specially designed chain to help operators avoid manual sharpening.
When a new chain is needed, the user will find no difficulty in changing it if he follows manufacturer's instructions. A new chain may "stretch" slightly when first used, so it should be operated initially at partial throttle and then adjusted.
Adhering to chain saw safety rules (see "Chain Saw Safety" above) will protect the user and the saw. It's basic, but worth mentioning: Be sure not to touch the cord of an electric chain saw with a blade when the saw is in operation.

Low-kickback chain has extra links or rakers added near the cutters which prevent the chain from cutting too deeply into the wood. This greatly reduces the risk of kickback. These chains can be retrofitted to older-model saws.

The United States Consumer Product Safety Commission points out that key features of the voluntary standard include a test for measuring the kickback potential of chain saws and the establishment of a maximum computed kickback angle limit of 45 degrees for gasoline-powered chain saws under 3.8 CID.

The standard also requires that all such chain saws must be equipped with a front hand guard plus at least two of the following: a low or reduced-kickback saw chain, tip or "nose" guards, chain brakes, reduced-kickback guide bars or some other feature that will reduce the risk of injury.

Reduced-kickback bars are designed with a smaller radius, which reduces the kickback area and contact area for cutters at the tip of the bar. Bar tip guards eliminate the possibility of cutting with the tip of the bar, thus eliminating the potential for kickback.

Another safety device is called a chain brake. It is intended to stop the moving chain on a running saw. When the saw begins to kick back, the user's hand, if correctly positioned, hits the chain brake to stop the saw. Be sure to read the owner's manual before using the saw and the need to regularly clean the brake of dirt and oil.

Other safety features include throttle latches for safer, easier starting; safety triggers to help avoid accidental acceleration; muffler shields and chain catchers to prevent a broken or slipped chain from lashing back at the operator; non-symmetrical bars, and low kickback chains.

The cutting length of a saw without a tip guard is greater than the bar length. It is actually twice the bar length. In other words, a saw with a 10" bar can be used to cut through a 20" diameter tree or log, half the diameter from each side.

You'll need to know the proper mixture of oil and gas, and the importance of keeping the saw chain oiled. Some saws have automatic oilers; others require hand pumping. The oil filter must be kept clean. The oil and gas must be drained from the saw when not in use.

To sharpen saws, you will need a file guide, depth gauge and proper files.

Chain Saw Safety
It pays to adhere to safe chain saw operation. Here are a few rules:
1. Read the instruction manual before operating the saw.
2. Wear gloves and safety goggles when working with the saw.
3. Wear proper garments when operating the saw. Clothing should be loose enough to permit free movement but not loose enough to snag on branches or get tangled in the chain. A safety-toed boot is also recommended.
4. Always start the saw on the ground or other firm base and be sure the chain and bar are in no danger of touching anything.
5. Stand to the side of the saw when cutting, never directly behind it.
6. Beware of "rotational kickback," the sudden upward and backward movement of the saw when the nose tip of the bar touches an object while the saw chain is moving.
7. Go slow in cutting. Chain saws cut so rapidly that it is easy to cut too deep or at the wrong angle. Don't press down on the bar in an attempt to make the saw cut faster. A properly sharpened chain will cut without pressure. Forcing it may damage the saw or injure the operator.
8. Always stop the engine before handing the saw to another person or moving it to a new location.
9. When finished with the saw, cover the bar and chain with a guard. If storing for a long period, empty the fuel tank.
10. Do not fill with gasoline when engine is either hot or running and do not smoke. Store the fuel in a safe container.
11. Keep saw clean of leaves and sawdust and keep handle free of grease.

Check your state and local codes before starting any project. Follow all safety precautions. Information in this document has been furnished by the North American Retail Hardware Association (NRHA) and associated contributors. Every effort has been made to ensure accuracy and safety. Neither NRHA, any contributor nor the retailer can be held responsible for damages or injuries resulting from the use of the information in this document.