Threading tool bits and center gage kit.

The bits are 5/16" High Speed Steel tool bits pre-sharpened for external and internal threading. Both bits have 55 degree and 60 degree cutting ends.

Used for grinding and setting screw cutting tools. American Unified National Standard - 60 degrees. Scales are used to determine number of threads per inch. Made of hardened spring tempered steel, with a protective satin chrome finish. All gaging surfaces are precision ground.