Abstract: A planetary screw includes a main screw having an outer threading and a connecting portion. A nut includes a hole extending through two end faces of the nut. The hole includes an inner periphery having an inner threading. A planetary unit includes a supporting mechanism and a plurality of rollers rotatably supported by the supporting mechanism to rotate in a fixed position. The plurality of rollers is identical to each other. Each of the plurality of rollers has an outer threading meshed with the outer threading of the main screw and the inner threading of the nut. The planetary screw can be used in a machine tool.

Abstract: A thread ring gauge includes a body having inner and outer peripheries spaced in a radial direction. The body includes a split extending from the outer periphery through the inner periphery, separating the body into two sections respectively having first and second end faces. The first end face includes a groove extending away from the second end face in a width direction perpendicular to the radial direction. The groove extends from the outer periphery towards but spaced from the inner periphery. The groove has a bottom wall facing the second end face. An adjusting member is extended through the first and second sections and movable to adjust a width of the slit between the first and second end faces in the width direction. A gauge block is received in the groove and abuts the bottom wall of the groove and the second end face.

Abstract: A thread ring gauge includes a body having inner and outer peripheries spaced in a radial direction. The body includes a split extending from the outer periphery through the inner periphery, separating the body into two sections respectively having first and second end faces. The first end face includes a groove extending away from the second end face in a width direction perpendicular to the radial direction. The groove extends from the outer periphery towards but spaced from the inner periphery. The groove has a bottom wall facing the second end face. An adjusting member is extended through the first and second sections and movable to adjust a width of the slit between the first and second end faces in the width direction. A gauge block is received in the groove and abuts the bottom wall of the groove and the second end face.