Abstract: A laser measuring system for incremental assemblies such as wire-wrapped frame assemblies used in spark chambers and the like is disclosed. The system utilizes a laser (10), an interferometer (11) and a retroreflector (12) to precisely measure distance. A light source (17) and a photodetector (18) are located adjacent the incremental assembly and mounted on a movable carriage (13). The interferometer (11) is also mounted on the movable carriage (13), while the laser (10) and retroreflector (12) are positioned at either end of the carriage track. The carriage (13) is moved along one edge of the incremental assembly between the retroreflector (12) and the laser (10), and as the carriage (13) is moved, the light from the light source (17) to the photodetector (18) is interrupted. This produces a trigger command to a control unit (20) which in turn causes a distance measurement to be made.