whipsaw

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A whipsaw or pitsaw was originally a type of saw used in a saw pit, and consisted of a narrow blade held rigid by a frame and called a frame saw or sash saw (see illustrations). This evolved into a straight, stiff blade without a frame, up to 14 feet long and with a handle at each end. The upper handle was called the tiller and the lower one the box, so called from its appearance and because it could be removed when the saw was taken out of one cut to be positioned in another. The whipsaw was used close to the felling site to reduce large logs to beams and planks.