Stihl TS 410 Instruction Manual - Page 17

can occur instantly and may result in the operator losing control of the cut-off machine, which, in turn, may result in serious or fatal injury. An understanding of the causes of these reactive forces will help you avoid them and loss of control. Reactive forces are exerted in a direction opposite to the direction in which the wheel is moving at the point of contact or of the pinching/binding. If the wheel is slowed by frictional contact with a solid object, the resulting reactive forces are normally moderate and readily controllable by an operator who is holding the machine properly. If, however, the wheel is abruptly slowed or stopped by a severe pinch or bind, the reactive forces may be substantially greater. The greater the force generated, the more difficult it will be for the operator to control the cut-off machine. Loss of control can result in severe personal injury or death. Pull-away, Climbing, Pinching and Rotational Kickback Forces the front of the wheel, the wheel may attempt to climb the object being cut (climbing). Pinching occurs when the piece being cut closes on the wheel. A severe binding may also occur if the wheel is substantially sideloaded in the cut or if an improper or damaged diamond cutting wheel begins or ceases to wobble in the kerf. The location of the pinch or bind on the wheel will determine the direction the machine will move in response to any reactive force that is generated - push back from the top of the wheel, pull away from areas below the upper quadrant of the wheel. However, if the wheel is severely pinched or bound in the upper quadrant at the front of the wheel, the wheel may be instantly thrown up and back towards the operator with significant force in a rotational kickback motion. Such kickback situations can and always should be avoided. Pinching or binding of the wheel can be prevented by proper support of the workpiece (see below), proper working technique (e.g., not side loading the wheel and standing outside the plane of the wheel) and by the use of properly designed, manufactured and maintained wheels that do not wobble or have friction-generating abrasive material on their sides. English Reducing the Risk of Kickback Injury WARNING To reduce the risk of kickback injury, avoid cutting with the upper quadrant of the wheel (illustrated above) whenever possible. Be especially cautious for a pinching or binding of the wheel in this area, which can cause severe reactive forces in a rotational kickback motion. 002BA582 ST 002BA553 AM 002BA146 KN The most common reactive forces are pull-away and climbing. If the contact is at the bottom of the wheel, a cut-off machine will try to pull away from the operator (pull-away). If the contact is at TS 410, TS 420 Avoid wedging action. The severed part of a workpiece must fall free and not wedge, bind or clamp the abrasive cutting wheel. 15