Some standard content:
National Metrology Verification Regulation of the People's Republic of China JJG25—2004
Screw Thread Micrometers
2004-09-21 Issued
2005-03-21 Implementation
General Administration of Quality Supervision, Inspection and Quarantine
JJG25—2004
Verification Regulation of
Screw Thread Micrometers
JJG25—2004
Replaces JJG25—1987
This regulation was approved by the General Administration of Quality Supervision, Inspection and Quarantine on September 21, 2004. And it will be implemented on March 21, 2005.
Responsible unit: National Technical Committee on Metrology of Geometric and Engineering Parameters Main drafting unit: Heilongjiang Metrology Verification and Testing Institute Participating drafting unit: Harbin Metrology Verification and Testing Institute Qinghai Measuring Tools and Blades Co., Ltd.
This regulation is entrusted to the National Technical Committee on Metrology of Geometric and Engineering Parameters to be responsible for the interpretation of this regulation Main drafters:
Liang Yuhong
Zhang Liping
Participating drafters:
Zong Yujuan
Yan Yonghong
JJG25—2004
(Heilongjiang Metrology Verification and Testing Institute)
(Heilongjiang Metrology Verification and Testing Institute)
(Harbin Metrology Verification and Testing Institute) Erbin Metrology Verification and Testing Institute)
(Qinghai Measuring Tools and Blades Co., Ltd.) 1
Scope·
References·
Overview·
Metrological performance requirements
4.1 Measuring force…
Grade width and width difference
JJG25-—2004
Distance from the end edge of the cone surface of the differential cylinder to the scale surface of the fixed sleeve Relative position of the end face of the cone surface of the differential cylinder and the millimeter scale of the fixed sleeve Surface roughness of the working surface of the conical probe, V-shaped probe and calibration rod Diameter of the probe mounting hole on the measuring rod and zero adjustment device: Dimensions of conical probe and V-shaped probe
Cone Symmetry of the working surface of the V-shaped probe and the V-shaped probe with respect to the axis of the handle and the coaxiality of the probe mounting hole on the measuring rod and the zero adjustment device. Indication error of the micrometer head
Angle of the working surface of the calibration rod
Working size of the calibration rod
Influence of the probe on the indication
Indication error
5 General technical requirements.
5.1 Appearance
Interaction of various parts
6 Control of measuring instruments
6.1 Verification conditions
Verification items·
Verification methods
Processing of verification results
Verification cycle
Appendix A
Appendix B
Uncertainty evaluation of the measurement results of the indication error of the thread micrometerAppendix C
Format of the inner pages of the calibration certificate and the calibration result notification (1)
: (5)
1 Scope
JJG25—2004
Calibration procedure for thread micrometers
This procedure is applicable to the initial calibration, subsequent calibration and in-service inspection of thread micrometers with graduation values of 0.01mm, 0.001mm, 0.002mm, 0.005mm, a measuring range of 25mm and a measuring range of (0~200)mm. 2 References
This specification refers to the following documents:
JF1001-1998 General metrological terms and definitions JJF1059-1999 Evaluation and expression of measurement uncertainty GB/T10932-2004 Thread micrometer
JJF1094-2002 Evaluation of measuring instrument characteristics When using this specification, attention should be paid to using the current valid versions of the above referenced documents. 3 Overview
Thread micrometer is a measuring tool that uses the principle of screw pair transmission to convert rotary motion into linear motion. It is mainly used to measure the middle diameter of external threads. Thread micrometers are divided into scale type and digital display type according to the reading form. Its structure is shown in Figures 1 and 2.
Figure 1 Structure of ruler-type thread micrometer
1—Zero adjustment device: 2—V-shaped probe: 3—Conical probe: 4—Micrometer screw: 5—Locking device; 6—Fixed sleeve: 7—Differential cylinder; 8—Force measuring device; 9—Ruler stand; 10—Heat insulation board; 11—Calibration rod 4 Metrological performance requirements
4.1 Measuring force
The measuring force should be within the range of (6~10)N.
4.2 Scale width and width difference
The width of the scale lines on the fixed sleeve and the differential cylinder is (0.15~0.20) mm; the scale width difference should not exceed 1
JJG25-2004
Figure 2 Structure of digital thread micrometer
1—Scale frame: 2, 6—Locking device: 3-V-shaped probe: 4—Conical probe: 5—Micrometer screw: 7 Insulation board; 8—Calibration rod; 9—Reading device; 10—Fixed sleeve: 11—Differential cylinder; 12—Force measuring device 4.3 The distance from the end edge of the cone surface of the differential cylinder to the scale surface of the fixed sleeve The distance from the end edge of the cone surface of the differential cylinder to the scale surface of the fixed sleeve should not exceed 0.4mm, as shown in Figure 3. a
Figure 3 Distance from the end face edge of the differential cone to the fixed sleeve scale line surface 4.4 Relative position of the end face of the differential cone and the millimeter scale of the fixed sleeve When the zero scale of the differential cone is aligned with the longitudinal scale of the fixed sleeve, the end face of the differential cone and the right edge of the millimeter scale of the fixed sleeve should be tangent. If not tangent, the pressure line shall not exceed 0.05mm and the line shall not exceed 0.1mm. 4.5 Surface roughness of the working surface of the conical probe, V-shaped probe and calibration rod The surface roughness of the working surface of the probe shall not exceed R, 0.40um, and the surface roughness of the working surface of the calibration rod shall not exceed R0.20um.
4.6 The aperture of the probe mounting hole on the measuring rod and the zero adjustment device is Φ3.5mm, Φ4mm, Φ5mm, and the tolerance is H7. 4.7 The dimensions of the conical probe and V-shaped probe
are shown in Table 1 and Figure 4.
Pitch range
JIG25-2004
Dimensions of conical probes and V-shaped probes
0.25~0.29
0.41~0.50
0.66~0.72
1.02~1.10
1.77~1.85
2.90~3.58
Tolerance value A
Conical probe
Tolerance value A
V-shaped probe
Figure 4 Dimensions of conical probes and V-shaped probes
4.8 The symmetry and half-angle deviation of the working surface of conical probes and V-shaped probes with respect to the axis of their shanks shall not exceed the requirements of Table 2.
4.9 The coaxiality of the probe mounting hole on the measuring rod and the zero adjustment device shall not exceed $0.005mm.
4.10 The indication error of the micrometer head
shall not exceed the provisions of Table 3.
0.14~0.18
0.22~0.29
0.34~0.48
0.55~0.70
1.00~1.20
1.70~2.70
JJG25--2004
Symmetry and half-angle deviation allowable values of the working surface of the conical probe and V-shaped probe with respect to the axis of its handle Table 2
Screw Pitch range
Symmetry of the probe working surface with respect to the axis of its shank (mm)
Deflection angle of the half angle (α/2) of the probe working surface()Www.bzxZ.net
Note: When the applicable pitch range of the probe is different from the pitch range in Table 2, it shall be based on the upper limit value of the pitch. For example, if the applicable pitch range of the probe is (3.5~4.0) mm, its symmetry and half-angle deviation shall conform to the corresponding values of the pitch range of (4.0~7.0) mm in Table 2.
Table 3 Indication error of micrometer head
Measuring range
75~100
100~125
125~150
150~175
175~200
4.11 The half-angle deviation of the working surface angle of the calibration rod
The allowable value is ±4'.
4.12 The working size of the calibration rod
Should not exceed the provisions of Table 4.
Table 4 Working size of the calibration rod
Nominal size
Maximum allowable error
Allowable value of size deviation
Nominal size
4.13 The influence of the measuring head on the indication
Should not exceed 0.005mm
4.14 Indication error
Should not exceed the provisions of Table 5.
5 General technical requirements
5.1 Appearance
JJG25--2004
Table 4 (Continued)
Table 5 Maximum allowable error
Allowable value of dimensional deviation
75~100
100~125
125~200
5.1.1 The first calibrated thread micrometer and calibration rod should not have appearance defects such as rust, bruises, and coating shedding, and the engraved lines should be clear and uniform. The subsequent calibrated thread micrometer should not have appearance defects that affect the quality of use. 5.1.2 The thread micrometer should be marked with the manufacturer's name (or trademark), factory number, measurement range and M mark. 5.1.3 The thread micrometer should be equipped with a set of conical probes and V-shaped probes. Each probe should indicate the measured pitch. The calibration rod should indicate the trademark and nominal size. 5.1.4 When moving the micrometer screw of the thread micrometer with counter, the counter should advance in sequence without disordered display; the differential indication value should be consistent with the counter display value; the center of each digit code should be on the same straight line parallel to the axis of the micrometer screw.
5.2 Interaction of various parts
5.2.1 The differential cylinder should be flexible and stable when rotating back and forth within the entire measuring range without jamming. 5
5.2.2 The locking device should function effectively. JIG25-2004
5.2.3 When adjusting the zero position with the zero adjustment device, it should be convenient and reliable. 5.2.4 The probe should rotate flexibly in the matching hole. 5.2.5 The measuring rod should not have axial motion and radial swing that can be felt by hand. 6 Control of measuring instruments
Control of measuring instruments includes initial calibration, subsequent calibration and in-use inspection. 6.1 Calibration conditions
6.1.1 Calibration environmental conditions
The indoor temperature for calibrating thread micrometers is (20±5)℃. The indoor temperature for calibrating and correcting measuring rods is (20±2)℃. The time for the micrometer to be calibrated to balance the temperature in the calibration room before calibration should be no less than 2h. 6.1.2 Calibration equipment
The main calibration equipment is shown in Table 6.
6.2 Calibration items
The calibration items are shown in Table 6.
Table 6 List of verification items and main verification equipment Verification category
Verification items
Interaction of various parts
Grade width and width difference
Distance from the end edge of the cone surface of the differential cylinder to the fixed
Grade surface of the casing
Relative position of the end surface of the cone surface of the differential cylinder and the fixed casing
Millimeter scale
Main verification equipment
Dynamometer with a graduation value not greater than 0.2N or| |tt||Force measuring device of equal accuracy
Tool microscope
Grade 2 feeler gauge or tool microscope
Surface roughness comparison sample or surface roughness
Surface roughness of working surface of conical probe, V-shaped probe and calibration
Measuring rod and probe installation on zeroing device
Aperture of hole
Dimensions of conical probe and V-shaped probe
Surface roughness of working surface of conical probe and V-shaped probe
|tt||Symmetry and half-angle deviation of the shank axis 6
Roughness measuring instrument
Smooth limit gauge
Tool microscope
Tool microscope
In use
Verification items
Installation of the probe on the measuring rod and the zeroing device
Coaxiality of the hole
Indication error of the micrometer head
Working surface angle of the calibration rod
Working size of the calibration rod||tt| |The influence of the measuring head on the indication
Indication error
JJG25—-2004
Table 6 (continued)
Main calibration equipment
Special gauges
Professional plane and spherical measuring heads 5 equal gauge blocks
Tool microscope
Three-needle, vertical optical gauge 4 equal gauge blocks
Thread gauge or calibration rod
Note: In the table, "+" indicates the items to be inspected, and "_" indicates the items that may not be inspected. 6.3 Verification method
6.3.1 Appearance
Visual observation.
6.3.2 Interaction between various parts
Visual observation and test.
6.3.3 Force measurement
Calibration category
In use
Use a dynamometer with a graduation value not greater than 0.2N or a force measuring device with equivalent accuracy for calibration. During calibration, install a special spherical probe on the measuring rod, see Figure 5, so that it contacts the plane and measures the force value. 0.4%
Figure 5 Special spherical probe for force measurement
6.3.4 Graduation line width and width difference
On the tool microscope, randomly check at least three evenly distributed graduation lines on the differential tube and the fixed sleeve. The graduation line width difference is determined by the difference between the maximum and minimum values.
6.3.5 The distance from the end edge of the cone surface of the differential tube to the graduation surface of the fixed sleeve is calibrated on the tool microscope. It can also be verified by comparison method with a feeler gauge with a thickness of 0.4mm. The verification should be carried out at no less than 3 positions within one rotation of the differential cylinder. The arbitration verification shall be based on the verification result on the tool microscope.
JJG25—2004
6.3.6 Relative position of the end face of the cone surface of the differential cylinder and the millimeter scale of the fixed sleeve When the zero scale of the differential cylinder is aligned with the longitudinal scale of the fixed sleeve, the end face of the cone surface of the differential cylinder and the right edge of the millimeter scale of the fixed sleeve should be tangent. If not, rotate the differential cylinder to make it tangent, and read the offset of its zero scale to the longitudinal scale of the fixed sleeve according to the differential cylinder. This offset is the value of the offline or pressed line, see Figure 6. (a) Pressing line 0.03mm
(b) Off-line 0.03mm
Figure 6 Relative position of the end face of the differential tube cone and the millimeter scale of the fixed sleeve 6.3.7 The surface roughness of the working surface of the conical probe, V-shaped probe and calibration rod shall be calibrated by the comparison method using a surface roughness comparison sample or measured using a surface roughness measuring instrument. The arbitration calibration shall be based on the calibration result on the surface roughness measuring instrument. 6.3.8 The aperture of the probe mounting hole on the measuring rod and the zero adjustment device shall be calibrated using a smooth limit gauge. The smooth limit gauge shall comply with the requirements of IT7 in JJG343-1996 "Smooth Limit Gauge Calibration Procedure".
6.3.9 Dimensions of conical probes and V-shaped probes The dimensions of conical probes and V-shaped probes shall be calibrated on a tool microscope and shall comply with the requirements of Table 1. 6.3.10 The symmetry and half-angle deviation of the working surface of the conical probe and V-shaped probe with respect to the axis of its handle are calibrated on a tool microscope.
6.3.11 The coaxiality of the probe mounting holes on the measuring rod and the zero adjustment device is calibrated with a special gauge. During calibration, the cylinders at both ends of the gauge should be able to be smoothly inserted into the holes on the measuring rod and the zero adjustment device. $A should meet the requirements of three specifications of Φ3.5mm, $4mm, and 5mm with a tolerance of h7. See Figure 7 and Table 7.
Table 7 Special gauge
Measuring range
75~100
100~125
125~2005 The measuring rod should not have axial movement and radial swing that can be felt by hand. 6 Measuring instrument control
Measuring instrument control includes initial calibration, subsequent calibration and in-use inspection. 6.1 Calibration conditions
6.1.1 Calibration environmental conditions
The indoor temperature for calibrating thread micrometers is (20±5)℃. The indoor temperature for calibrating and correcting measuring rods is (20±2)℃. The time for the micrometer to be tested to balance the temperature in the calibration room before calibration should be no less than 2h. 6.1.2 Calibration equipment
The main calibration equipment is shown in Table 6.
6.2 Calibration items
The calibration items are shown in Table 6.
Table 6 List of verification items and main verification equipment Verification category
Verification items
Interaction of various parts
Grade width and width difference
Distance from the end edge of the cone surface of the differential cylinder to the fixed
Grade surface of the casing
Relative position of the end surface of the cone surface of the differential cylinder and the fixed casing
Millimeter scale
Main verification equipment
Dynamometer with a graduation value not greater than 0.2N or| |tt||Force measuring device of equal accuracy
Tool microscope
Grade 2 feeler gauge or tool microscope
Surface roughness comparison sample or surface roughness
Surface roughness of working surface of conical probe, V-shaped probe and calibration
Measuring rod and probe installation on zeroing device
Aperture of hole
Dimensions of conical probe and V-shaped probe
Surface roughness of working surface of conical probe and V-shaped probe
|tt||Symmetry and half-angle deviation of the shank axis 6
Roughness measuring instrument
Smooth limit gauge
Tool microscope
Tool microscope
In use
Verification items
Installation of the probe on the measuring rod and the zeroing device
Coaxiality of the hole
Indication error of the micrometer head
Working surface angle of the calibration rod
Working size of the calibration rod||tt| |The influence of the measuring head on the indication
Indication error
JJG25—-2004
Table 6 (continued)
Main calibration equipment
Special gauges
Professional plane and spherical measuring heads 5 equal gauge blocks
Tool microscope
Three-needle, vertical optical gauge 4 equal gauge blocks
Thread gauge or calibration rod
Note: In the table, "+" indicates the items to be inspected, and "_" indicates the items that may not be inspected. 6.3 Verification method
6.3.1 Appearance
Visual observation.
6.3.2 Interaction between various parts
Visual observation and test.
6.3.3 Force measurement
Calibration category
In use
Use a dynamometer with a graduation value not greater than 0.2N or a force measuring device with equivalent accuracy for calibration. During calibration, install a special spherical probe on the measuring rod, see Figure 5, so that it contacts the plane and measures the force value. 0.4%
Figure 5 Special spherical probe for force measurement
6.3.4 Graduation line width and width difference
On the tool microscope, randomly check at least three evenly distributed graduation lines on the differential tube and the fixed sleeve. The graduation line width difference is determined by the difference between the maximum and minimum values.
6.3.5 The distance from the end edge of the cone surface of the differential tube to the graduation surface of the fixed sleeve is calibrated on the tool microscope. It can also be verified by comparison method with a feeler gauge with a thickness of 0.4mm. The verification should be carried out at no less than 3 positions within one rotation of the differential cylinder. The arbitration verification shall be based on the verification result on the tool microscope.
JJG25—2004
6.3.6 Relative position of the end face of the cone surface of the differential cylinder and the millimeter scale of the fixed sleeve When the zero scale of the differential cylinder is aligned with the longitudinal scale of the fixed sleeve, the end face of the cone surface of the differential cylinder and the right edge of the millimeter scale of the fixed sleeve should be tangent. If not, rotate the differential cylinder to make it tangent, and read the offset of its zero scale to the longitudinal scale of the fixed sleeve according to the differential cylinder. This offset is the value of the offline or pressed line, see Figure 6. (a) Pressing line 0.03mm
(b) Off-line 0.03mm
Figure 6 Relative position of the end face of the differential tube cone and the millimeter scale of the fixed sleeve 6.3.7 The surface roughness of the working surface of the conical probe, V-shaped probe and calibration rod shall be calibrated by the comparison method using a surface roughness comparison sample or measured using a surface roughness measuring instrument. The arbitration calibration shall be based on the calibration result on the surface roughness measuring instrument. 6.3.8 The aperture of the probe mounting hole on the measuring rod and the zero adjustment device shall be calibrated using a smooth limit gauge. The smooth limit gauge shall comply with the requirements of IT7 in JJG343-1996 "Smooth Limit Gauge Calibration Procedure".
6.3.9 Dimensions of conical probes and V-shaped probes The dimensions of conical probes and V-shaped probes shall be calibrated on a tool microscope and shall comply with the requirements of Table 1. 6.3.10 The symmetry and half-angle deviation of the working surface of the conical probe and V-shaped probe with respect to the axis of its handle are calibrated on a tool microscope.
6.3.11 The coaxiality of the probe mounting holes on the measuring rod and the zero adjustment device is calibrated with a special gauge. During calibration, the cylinders at both ends of the gauge should be able to be smoothly inserted into the holes on the measuring rod and the zero adjustment device. $A should meet the requirements of three specifications of Φ3.5mm, $4mm, and 5mm with a tolerance of h7. See Figure 7 and Table 7.
Table 7 Special gauge
Measuring range
75~100
100~125
125~2005 The measuring rod should not have axial movement and radial swing that can be felt by hand. 6 Measuring instrument control
Measuring instrument control includes initial calibration, subsequent calibration and in-use inspection. 6.1 Calibration conditions
6.1.1 Calibration environmental conditions
The indoor temperature for calibrating thread micrometers is (20±5)℃. The indoor temperature for calibrating and correcting measuring rods is (20±2)℃. The time for the micrometer to be tested to balance the temperature in the calibration room before calibration should be no less than 2h. 6.1.2 Calibration equipment
The main calibration equipment is shown in Table 6.
6.2 Calibration items
The calibration items are shown in Table 6.
Table 6 List of verification items and main verification equipment Verification category
Verification items
Interaction of various parts
Grade width and width difference
Distance from the end edge of the cone surface of the differential cylinder to the fixed
Grade surface of the casing
Relative position of the end surface of the cone surface of the differential cylinder and the fixed casing
Millimeter scale
Main verification equipment
Dynamometer with a graduation value not greater than 0.2N or| |tt||Force measuring device of equal accuracy
Tool microscope
Grade 2 feeler gauge or tool microscope
Surface roughness comparison sample or surface roughness
Surface roughness of working surface of conical probe, V-shaped probe and calibration
Measuring rod and probe installation on zeroing device
Aperture of hole
Dimensions of conical probe and V-shaped probe
Surface roughness of working surface of conical probe and V-shaped probe
|tt||Symmetry and half-angle deviation of the shank axis 6
Roughness measuring instrument
Smooth limit gauge
Tool microscope
Tool microscope
In use
Verification items
Installation of the probe on the measuring rod and the zeroing device
Coaxiality of the hole
Indication error of the micrometer head
Angle of the working surface of the calibration rod
Working size of the calibration rod||tt| |The influence of the measuring head on the indication
Indication error
JJG25—-2004
Table 6 (continued)
Main calibration equipment
Special gauges
Professional plane and spherical measuring heads 5 equal gauge blocks
Tool microscope
Three-needle, vertical optical gauge 4 equal gauge blocks
Thread gauge or calibration rod
Note: In the table, "+" indicates the items to be inspected, and "_" indicates the items that may not be inspected. 6.3 Verification method
6.3.1 Appearance
Visual observation.
6.3.2 Interaction between various parts
Visual observation and test.
6.3.3 Force measurement
Calibration category
In use
Use a dynamometer with a graduation value not greater than 0.2N or a force measuring device with equivalent accuracy for calibration. During calibration, install a special spherical probe on the measuring rod, see Figure 5, so that it contacts the plane and measures the force value. 0.4%
Figure 5 Special spherical probe for force measurement
6.3.4 Graduation line width and width difference
On the tool microscope, randomly check at least three evenly distributed graduation lines on the differential tube and the fixed sleeve. The graduation line width difference is determined by the difference between the maximum and minimum values.
6.3.5 The distance from the end edge of the cone surface of the differential tube to the graduation surface of the fixed sleeve is calibrated on the tool microscope. It can also be verified by comparison method with a feeler gauge with a thickness of 0.4mm. The verification should be carried out at no less than 3 positions within one rotation of the differential cylinder. The arbitration verification shall be based on the verification result on the tool microscope.
JJG25—2004
6.3.6 Relative position of the end face of the cone surface of the differential cylinder and the millimeter scale of the fixed sleeve When the zero scale of the differential cylinder is aligned with the longitudinal scale of the fixed sleeve, the end face of the cone surface of the differential cylinder and the right edge of the millimeter scale of the fixed sleeve should be tangent. If not, rotate the differential cylinder to make it tangent, and read the offset of its zero scale to the longitudinal scale of the fixed sleeve according to the differential cylinder. This offset is the value of the offline or pressed line, see Figure 6. (a) Pressing line 0.03mm
(b) Off-line 0.03mm
Figure 6 Relative position of the end face of the differential tube cone and the millimeter scale of the fixed sleeve 6.3.7 The surface roughness of the working surface of the conical probe, V-shaped probe and calibration rod shall be calibrated by the comparison method using a surface roughness comparison sample or measured using a surface roughness measuring instrument. The arbitration calibration shall be based on the calibration result on the surface roughness measuring instrument. 6.3.8 The aperture of the probe mounting hole on the measuring rod and the zero adjustment device shall be calibrated using a smooth limit gauge. The smooth limit gauge shall comply with the requirements of IT7 in JJG343-1996 "Smooth Limit Gauge Calibration Procedure".
6.3.9 Dimensions of conical probes and V-shaped probes The dimensions of conical probes and V-shaped probes shall be calibrated on a tool microscope and shall comply with the requirements of Table 1. 6.3.10 The symmetry and half-angle deviation of the working surface of the conical probe and V-shaped probe with respect to the axis of its handle are calibrated on a tool microscope.
6.3.11 The coaxiality of the probe mounting holes on the measuring rod and the zero adjustment device is calibrated with a special gauge. During calibration, the cylinders at both ends of the gauge should be able to be smoothly inserted into the holes on the measuring rod and the zero adjustment device. $A should meet the requirements of three specifications of Φ3.5mm, $4mm, and 5mm with a tolerance of h7. See Figure 7 and Table 7.
Table 7 Special gauge
Measuring range
75~100
100~125
125~2005 The distance from the end edge of the differential cylinder cone to the fixed sleeve scale line surface is calibrated on a tool microscope. It can also be calibrated by comparison method with a feeler gauge with a thickness of 0.4mm. The calibration should be carried out at no less than 3 positions within one rotation of the differential cylinder. The arbitration calibration is based on the calibration result on the tool microscope.
JJG25—2004
6.3.6 The relative position of the end face of the differential cylinder cone and the millimeter scale of the fixed sleeve When the zero scale of the differential cylinder is aligned with the longitudinal scale of the fixed sleeve, the end face of the differential cylinder cone and the right edge of the millimeter scale of the fixed sleeve should be tangent. If not, rotate the differential cylinder to make it tangent, and read the offset of its zero scale to the longitudinal scale of the fixed sleeve according to the differential cylinder. This offset is the value of the offline or press line, see Figure 6. (a) Pressing line 0.03mm
(b) Off-line 0.03mm
Figure 6 Relative position of the end face of the differential tube cone and the millimeter scale of the fixed sleeve 6.3.7 The surface roughness of the working surface of the conical probe, V-shaped probe and calibration rod shall be calibrated by the comparison method using a surface roughness comparison sample or measured using a surface roughness measuring instrument. The arbitration calibration shall be based on the calibration result on the surface roughness measuring instrument. 6.3.8 The aperture of the probe mounting hole on the measuring rod and the zero adjustment device shall be calibrated using a smooth limit gauge. The smooth limit gauge shall comply with the requirements of IT7 in JJG343-1996 "Smooth Limit Gauge Calibration Procedure".
6.3.9 Dimensions of conical probes and V-shaped probes The dimensions of conical probes and V-shaped probes shall be calibrated on a tool microscope and shall comply with the requirements of Table 1. 6.3.10 The symmetry and half-angle deviation of the working surface of the conical probe and V-shaped probe with respect to the axis of its handle are calibrated on a tool microscope.
6.3.11 The coaxiality of the probe mounting holes on the measuring rod and the zero adjustment device is calibrated with a special gauge. During calibration, the cylinders at both ends of the gauge should be able to be smoothly inserted into the holes on the measuring rod and the zero adjustment device. $A should meet the requirements of three specifications of Φ3.5mm, $4mm, and 5mm with a tolerance of h7. See Figure 7 and Table 7.
Table 7 Special gauge
Measuring range
75~100
100~125
125~2005 The distance from the end edge of the differential cylinder cone to the fixed sleeve scale line surface is calibrated on a tool microscope. It can also be calibrated by comparison method with a feeler gauge with a thickness of 0.4mm. The calibration should be carried out at no less than 3 positions within one rotation of the differential cylinder. The arbitration calibration is based on the calibration result on the tool microscope.
JJG25—2004
6.3.6 The relative position of the end face of the differential cylinder cone and the millimeter scale of the fixed sleeve When the zero scale of the differential cylinder is aligned with the longitudinal scale of the fixed sleeve, the end face of the differential cylinder cone and the right edge of the millimeter scale of the fixed sleeve should be tangent. If not, rotate the differential cylinder to make it tangent, and read the offset of its zero scale to the longitudinal scale of the fixed sleeve according to the differential cylinder. This offset is the value of the offline or press line, see Figure 6. (a) Pressing line 0.03mm
(b) Off-line 0.03mm
Figure 6 Relative position of the end face of the differential tube cone and the millimeter scale of the fixed sleeve 6.3.7 The surface roughness of the working surface of the conical probe, V-shaped probe and calibration rod shall be calibrated by the comparison method using a surface roughness comparison sample or measured using a surface roughness measuring instrument. The arbitration calibration shall be based on the calibration result on the surface roughness measuring instrument. 6.3.8 The aperture of the probe mounting hole on the measuring rod and the zero adjustment device shall be calibrated using a smooth limit gauge. The smooth limit gauge shall comply with the requirements of IT7 in JJG343-1996 "Smooth Limit Gauge Calibration Procedure".
6.3.9 Dimensions of conical probes and V-shaped probes The dimensions of conical probes and V-shaped probes shall be calibrated on a tool microscope and shall comply with the requirements of Table 1. 6.3.10 The symmetry and half-angle deviation of the working surface of the conical probe and V-shaped probe with respect to the axis of its handle are calibrated on a tool microscope.
6.3.11 The coaxiality of the probe mounting holes on the measuring rod and the zero adjustment device is calibrated with a special gauge. During calibration, the cylinders at both ends of the gauge should be able to be smoothly inserted into the holes on the measuring rod and the zero adjustment device. $A should meet the requirements of three specifications of Φ3.5mm, $4mm, and 5mm with a tolerance of h7. See Figure 7 and Table 7.
Table 7 Special gauge
Measuring range
75~100
100~125
125~200
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