A threaded shaft measuring device includes a table that supports a threaded shaft to be measured, and that is capable of adjusting a rotation position about a perpendicular Z axis, adjusting a rotation position about an X axis that is horizontal and intersects with the Z axis, and adjusting a position in a Y axis direction that is horizontal and intersects with the X axis; and a stylus that performs scanning measurement of a surface of the threaded shaft. An adjustment jig capable of making contact with the threaded shaft and an elevator that brings the adjustment jig into contact with the threaded shaft are installed on the table. The adjustment jig includes an abutting bottom surface; an abutting side surface; a measurement surface; and an axis line marker that enables a tilt relative to the X axis to be detected.

A thread gauge, which allows to reliably know the time for replacement by visual checking and improves the predetermined dimensional accuracy of a thread product has a go-side thread measuring portion extending from one side of a shank portion coaxially with the shank portion or a not-go-side thread measuring portion extending from an other side of the shank portion coaxially with the shank portion, a wear checking gauge line having a predetermined length and a predetermined depth formed on male thread portions and female thread portions formed on the go-side thread measuring portion or the not-go-side thread measuring portion.

A step gauge includes: measurement blocks each having reference measurement surfaces; interval blocks each interposed between a pair of ones of the measurement blocks to keep a distance between the pair of ones of the measurement blocks at a predetermined distance, the measurement blocks and the interval blocks being alternately aligned one by one in one direction. The measurement blocks and the interval blocks each have a coefficient of linear thermal expansion of less than 0.0310.sup.6(1/K) and have through holes aligned in the one direction. The step gauge further includes a tie rod inserted in the through holes and countersunk screws respectively fixed to ends of the tie rod. The tie rod is made of a material having a coefficient of linear thermal expansion of less than 0.510.sup.6(1/K).

An assembly for measuring wear of a barrel and feedscrew combination, wherein the barrel has a longitudinally extending feedscrew disposed therein and a radially extending measuring aperture formed in a wall thereof, includes a measuring probe having a proximity detecting sensor, a barrel plug for removable insertion into the measuring aperture, and a measuring fixture. The barrel plug is configured to undergo wear in an axial direction thereof while inserted into the measuring aperture. The measuring probe and the barrel plug are installed into the measuring fixture for determining wear of the barrel plug in the axial direction thereof. The measuring probe is further configured for removable insertion into the measuring aperture for measuring wear of a flight of the feedscrew. A spacer and rotational tool cooperate with the measuring probe when installing the measuring probe in the measuring aperture.

A measuring probe for measuring a screw groove of a relatively rotatable ball screw includes a stylus having a tip end portion configured to contact the screw groove, a radial-direction displacement mechanism configured to support the stylus so as for the stylus to be displaceable in an X direction toward an axial center of the ball screw, an axial-direction displacement mechanism configured to support the stylus so as for the stylus to be displaceable in an axial direction (Z direction) of the axial center, and sensors configured to detect displacement of the stylus produced by the radial-direction displacement mechanism and the axial-direction displacement mechanism. This enables high-accuracy measurement of a predetermined position of a side surface of a relatively rotatable work.

A measuring probe for measuring a screw groove of a relatively rotatable ball screw includes a stylus having a tip end portion configured to contact the screw groove, a radial-direction displacement mechanism configured to support the stylus so as for the stylus to be displaceable in an X direction toward an axial center of the ball screw, an axial-direction displacement mechanism configured to support the stylus so as for the stylus to be displaceable in an axial direction (Z direction) of the axial center, and sensors configured to detect displacement of the stylus produced by the radial-direction displacement mechanism and the axial-direction displacement mechanism. This enables high-accuracy measurement of a predetermined position of a side surface of a relatively rotatable work.

A thread gauge inspection apparatus includes a receiving member to hold a reference thread gauge and a motor to bi-directionally rotate the reference thread gauge. A counter counts a number of turns the reference thread gauge is rotated by the motor, and a torque monitoring device monitors the torque produced by the motor as the reference thread gauge is rotated. A controller, when the monitored torque exceeds a predetermined value, causes the motor to stop rotating the reference thread gauge and causes the counter to stop counting the number of turns the reference thread gauge is rotated. The controller compares the count produced by the counter with an inputted specific turn count and indicates the thread quality of threaded hole or a threaded stud passed inspection when the count produced by the counter is equal to the inputted specific turn count.

A device for identifying bolts and nuts can include a plurality of threaded bodies, wherein each threaded body of the plurality of threaded bodies includes: a female threaded portion; and a male threaded portion, the male threaded portion being connected to the female threaded portion; wherein the female threaded portion and the male threaded portion extend in opposite directions; a flexible connector including a plurality of flexible portions that connect the plurality of threaded bodies; wherein each flexible portion of the plurality of flexible portions has a height, a width and a length, the length being larger than the width, and the height being larger than the width so that the flexible connector is more flexible along a first plane than a second plane perpendicular to the first plane.