The Unified National Miniature Thread Series (miniature metric thread) was accepted as a new thread series in 1958 and was intended for general-purpose use in instruments, miniature mechanisms, and for jewelry and watches. The use of this series is recommended for all new products in place of the old standard miniature and the many improvised thread sizes still in existence. We will continue to supply the ongoing demand for the old standard miniature screw threads.
The UNM thread series has fourteen miniature metric thread sizes that are systematically distributed from .30mm to 1.40mm in diameter and supplements the Unified and American Thread Series that begins at .060 inch diameter. The diameter-pitch combinations provide for maximum strength against stripping and for excellent manufacturability and interchangeability.