GB/T 10932-2024Screw thread micrometer (English PDF)

4.1 Types

4.1.1 A schematic diagram of a rotary screw thread micrometer is shown in Figure 1, and a schematic diagram of a straight-in screw thread micrometer is shown in Figure 2. The illustrations are for illustrative purposes only and do not represent detailed structures.

4.1.2 Schematic diagrams of V-shaped and conical measuring heads are shown in Figure

3.The illustrations are for illustrative purposes only.

4.1.3 Schematic diagrams of the V-shaped measuring head and knife-edge measuring head are shown in Figure

4.The illustrations are for illustrative purposes only.

4.2 Basic parameters

4.2.1 The measuring range of a screw thread micrometer should be 0 mm~25 mm, 25 mm~50 mm, 50 mm~75 mm, 75 mm~100 mm, 100 mm~125 mm, 125 mm~150 mm, 150 mm~175 mm, 175 mm~200 mm, 200 mm~225 mm, 225 mm~250 mm, 250 mm~275 mm, and 275 mm~300 mm.

4.2.2 The pitch of the micrometer spindle of a screw thread micrometer should be

0.5 mm or 1 mm.

4.2.3 The nominal diameter of the smooth cylindrical part of the micrometer spindle extending out of the frame should preferably be

4.2.4 The parameters of the screw thread micrometer measuring head should be as specified in Table 1.

5.1 Appearance

5.1.1 The surface of the screw thread micrometer shall be free from defects such as cracks, scratches, dents, rust, and burrs that affect its appearance and performance.

5.5 Interactions

5.5.1 The micrometer spindle and nut shall be fully engaged and well-fitted throughout the full measuring range, without any jamming or significant axial movement. The axial movement of a rotary screw thread micrometer shall not exceed

0.01 mm, and the axial movement of a straight-in screw thread micrometer shall not exceed

0.02 mm.

5.5.2 The smooth cylindrical part of the micrometer spindle extending from the scale frame shall fit well with the bushing, and there shall be no obvious radial wobble. The radial wobble value should not exceed

0.01 mm.

5.6 Force measuring device The screw thread micrometer shall have a force-measuring device. When the micrometer spindle is moved by the force measuring device, the force acting on the contact surface between the measuring surface (plane) of the micrometer spindle and the spherical surface shall be 5 N~10 N, and the variation shall not exceed 2 N.

5.7 Locking device For rotary screw thread micrometers, there shall be a device that can effectively lock the micrometer spindle; when locked, the difference in distance between the two measuring surfaces shall not exceed 2.0 µm compared to when unlocked.

5.8 Measuring surface

5.8.1 The hardness of the measuring surfaces of alloy tool steel shall not be less than 740 HV (or

61.8 HRC); the hardness of the measuring surfaces of stainless steel shall not be less than 552 HV (or

52.5 HRC). Hardness requirements are not specified for the measuring surfaces of cemented carbide.

5.8.2 The surface roughness Ra of the measuring surface shall not be greater than 0.4 µm.

5.9 Scale Refer to the requirements of section

5.9 in GB/T 1216-2018.

5.10 Calibration measuring rod

5.10.1 The screw thread micrometer shall be provided with an adjustment tool for adjusting the zero position.

5.10.2 For screw thread micrometers with a lower measurement limit greater than 25 mm, a calibration measuring rod shall be provided. The nominal dimensions and dimensional deviations of the calibration measuring rod are specified in Table