The Starrett 257B full-sized surface gauge has both a 9"/225mm and a 12"/300mm spindle for mounting onto a hardened steel base, with a 6" scriber for accurately scribing lines, transferring measurements, and probing surfaces in inspection work. The spindles are 5/16" in diameter. The included scriber is 6" (150mm) in length and 9/64" (3.6mm) in diameter, and is held to the spindle by a sliding snug with a knurled, ring-type lock nut for secure positioning. The steel base is hardened, ground, and lapped for a smooth, flat surface, and measures 2-7/8 x 2-3/8 inches /72 x 60mm (W x D; W is width, the horizontal distance from left to right; D is depth, the horizontal distance from front to back). Four frictionally held gauge pins in the base can be pushed down and referenced against the edge of a surface plate or T-slot for linear work. The satin chrome finish resists rust and is glare-free. A surface gauges is a tool for machinists and toolmakers to mark lines on a workpiece, transfer measurements from one workpiece to another, and for probing surfaces in inspection work.
The L.S. Starrett Company manufactures precision measuring tools, metrology and testing equipment, and saw blade products. The company, founded in 1880, is headquartered in Athol, MA.
