TB 9-5210-207-24
Table 3. Gage Block Stacks
Micrometer head
Equivalent gage block stacks
checkpoint (in.)
between end stops (in.)
1/
in. micrometer
0
1.500
2
head movement
0.250
1.750
0.500
2.000
1 in. micrometer
0
2.000
head movement
0.500
2.500
1.000
3.000
b. Adjustments
(1) Tighten slotted nut on TI to remove any backlash.
(2) Zero set TI micrometer head at its minimum size in accordance with the
manufacturer's instructions.
9. Length Calibration
a. Performance Check
(1) Verify each extension rod and/or caps in combination with micrometer head,
using the techniques in paragraph 8 a (1) through (3) above. Verify only the minimum
indication for each combination.
(2) The gage block dimensions used to verify each setup must be equal to the
minimum length of the extension rod, micrometer head, and end-cap combination (size
marked on each extension rod) to be verified.
(3) The permissible error in length will not exceed the applicable tolerances
specified in tables 4 through 10.
Table 4. Inside Micrometer, Caliper, with Jaws, (English Measure) Permissible Error - Inches
Length ( )
Size
Range
0.001 Graduations
0.0001 Graduations
1
0.200 to 1
0.0005
0.0002
1/2
/
1
0.500 to 11 2
0.0005
0.0002
2
1 to 2
0.0005
0.0002
Table 5. Inside Micrometer, Rod and Sleeve (English Measure) Permissible Error - Inches
Length ( )
Range
0.001 Graduations
0.0001 Graduations
1 to 2
0.0005
0.0003
2 to 8
0.0005
0.0004
2 to 12
0.0005
0.0005
8 to 32
0.001
0.001
8 to 36
0.001
0.001