Abstract: A micrometer having a bushing and a measuring spindle extending through the bushing, the spindle and bushing having confronting surfaces and including means permitting movement of the spindle with respect to the bushing in a single direction and for preventing relative movement of the spindle and bushing in other directions. A bearing having a spheroidal surface protrudes from one of the confronting surfaces with the spheroidal surface in contact with walls of a groove formed in the other confronting surface, the groove extending in the single desired direction. Means are provided to resiliently urge the bearing into the groove and to permit resilient radial movement of the bearing with respect to the spindle while maintaining contact of the spheroidal surface of bearing with walls of the groove.