Starrett 579A-12 self-centering telescoping gage measures internal diameters from 5/16 to 1/2 inch. Steel construction with satin chrome finish provides durability and corrosion resistance. Rigid handle design ensures stable measurements. Overall dimensions are 12.796 inches long by 0.281 inches wide by 0.507 inches high.

The Starrett 579 Telescoping Gage is used for determining the true size of holes, slots, and recesses up to 6" (150mm). The ends of both contacts are hardened and ground to a radius to allow proper clearance on the smallest hole the gage will enter. The tool must be slightly rocked in the hole being measured to ensure that the tool is on the proper diameter before it is locked and withdrawn. The final hole size is obtained by measuring over the gage contacts with a micrometer. 5/16-1/2" (8-13mm) Range, 12" (300mm) Handle.

Features

• Precision ground radius on each gage provides two-point contact for maximum accuracy
• Greater range
• Constant spring tension gives uniform contact pressure
• Both plungers are easily locked at any desired setting
• Handles are rigidly attached to the contact plungers and are automatically self-centering
• Ends of both contacts are hardened and ground to a radius to allow proper clearance on the smallest hole the gage will enter