Stihl MSE 210 C-BQ Instruction Manual - Page 13

Kickback may occur when the moving saw chain near the upper quadrant of the bar nose contacts a solid object or is pinched. When this occurs, the energy driving the saw chain can create a force that moves the chain saw in a direction opposite to the saw chain movement at the point where the saw chain is slowed or stopped. This may fling the bar up and back in a lightning fast reaction mainly in the plane of the bar and can cause severe or fatal injury to the operator. Kickback may occur, for example, when the saw chain near the upper quadrant of the bar nose contacts the wood or is pinched during limbing or when it is incorrectly used to begin a plunge or boring cut. 001BA035 KN The greater the force of the kickback reaction, the more difficult it becomes for the operator to control the chain saw. Many factors influence the occurrence and force of the kickback reaction. These include saw chain speed, the speed at which the bar and saw chain contact the object, the angle of contact, the condition of the saw chain and other factors. The type of bar and saw chain you use is an important factor in the occurrence and force of the kickback reaction. Some STIHL bar and saw chain types are designed to reduce kickback forces. STIHL recommends the use of reduced kickback bars and low kickback chains. Chain Saw Kickback Standard The following standards apply with respect to kickback: - § 19.108 of UL 60745-2-13 - § 5.11 of ANSI/OPEI B175.1-2012 These standards, in the following referred to as "the chain saw kickback standards" set certain performance and design criteria related to chain saw kickback. To comply with the chain saw kickback standards, electric chain saws - must, in their original condition, meet a 45° computer derived kickback angle when equipped with certain cutting attachments, - and must be equipped with at least two devices to reduce the risk of kickback injury, such as a chain brake, low kickback chain, reduced kickback bar, etc. English The computer derived angles for electric saws are measured by applying a computer program to test results from the kickback test machine. WARNING The computer derived angles of the chain saw standards may bear no relationship to actual kickback bar rotation angles that may occur in real life cutting situations. In addition, features designed to reduce kickback injuries may lose some of their effectiveness when they are no longer in their original condition, especially if they have been improperly maintained. Compliance with the chain saw kickback standards does not automatically mean that in a real life kickback the bar and saw chain will rotate at most 45°. WARNING In order for chain saws to comply with the computed kickback angle requirements of the chain saw kickback standards use only the following cutting attachments: - bar and saw chain combinations listed as complying in the "Specifications" section of the instruction manual or - other replacement bar and saw chain combinations marked in accordance with the standards for use on the chain saw or - replacement saw chain designated "low kickback saw chain.'' See the section on "Low Kickback Saw Chain and Reduced Kickback Bars." MSE 170 C, MSE 210 C 11