Backgauges

Backgauges are precision devices used on machine tools to position stock at a fixed distance from the working edge, enabling repeatable cuts and consistent part dimensions. A back gauge typically consists of a reference fence or rail, a sliding gauge element that contacts the workpiece, a stop or block that defines the measurement, a scale or digital readout for setting the distance, and a locking mechanism to fix the position. Materials are usually stainless or hardened steel for accuracy and durability.

Backgauges are common in metalworking and woodworking. They are used on guillotine or mechanical shears to set the distance from the blade, on punch presses to index parts for punching, on table saws and panel saws to set stop length, and on milling or drilling machines to guide repetitive operations. Manual backgauges rely on a user to slide and clamp the gauge; modern versions may include digital readouts, servo motors, or pneumatic/hydraulic actuation for automated or semi-automated operation.

Operation typically involves aligning the workpiece against the back gauge, adjusting the stop to the desired length, tightening the lock, and then performing the cut or operation. For high precision, calibration against a master and periodic verification are recommended. Maintenance includes cleaning the rails, ensuring smooth travel of the gauge, and lubricating sliding surfaces.

Variants include automated or CNC backgauges, pneumatic or hydraulic backgauges on presses, and integrated backgauges on panel saws and turret punches. Safety considerations include secure locking and proper stock support to prevent misalignment or kickback.