Low-kickback (safety) chain Kickback occurs when the upper tip of the guide bar touches an object or when the wood closes in and pinches the saw chain in the cut. This contact may cause a lightning-fast reverse action of the guide bar back toward the operator, possibly resulting in severe upper-body, neck and facial lacerations or even death (Figure 1). One major difference between a professional and consumer chain saw is that a consumer saw must be equipped with a low-kickback, or safety,

The camera was made of brass, and was screwed into one end of a box-shaped tube of wood. At the far end was a square opening over which the glass negative plate was clamped. This held the image that was to be micro-photographed and multiplied many times.