backgauge

A backgauge is a device used on cutting, punching, or machining equipment to position stock at a precise distance from the cutting edge or reference surface, enabling repeatable cuts or punches. It typically consists of a rigid fence or slide, a scale or digital readout, and one or more adjustable stops or carriers that hold or clamp the workpiece. On sheet metal shears and punches, the backgauge is mounted behind the blade and can be moved along a track to set the desired stop position. On woodworking saws or routers, a backgauge functions similarly as a fence that sets the length of each piece.

Operation involves measuring or recalling the required length, moving the backgauge to align with the desired position, locking the stop, and feeding the material into the blade or die. The workpiece is held by clamps or hold-downs to prevent movement during cutting or punching.

Types range from manual backgauges, which use a hand crank or sliding bar, to mechanical backgauges with rack-and-pinion or screw drives; hydraulic or pneumatic backgauges automate movement for high-volume production; and digital backgauges provide electronic readouts and memory for repeated settings.

Applications are common in metalworking for shearing and punching, and in woodworking and other fabrication contexts where repeatable piece lengths are required.

Maintenance and safety considerations include regular calibration against a reference scale, checking alignment after heavy use, lubrication of moving parts, and ensuring guards and clamps are in place. Operators should keep hands away from cutting edges during operation.