TB 55-5210-252-35/1
7. Accessories required. None.
Section III. PRELIMINARY OPERATIONS
8. Preliminary instructions.
NOTE
Personnel should familiarize themselves with the entire
bulletin prior to performing calibration.
9. Equipment setup.
a. Select a clean work area and allow test instrument and standards to stabilize at existing temperature.
b. If the test instrument is not within tolerance, perform the specified adjustment and continue performance
check. When test instrument is not within tolerance and no adjustment is specified, the deficiency must be cor-
rected before continuing with the procedure.
Section IV. CALIBRATION PROCESS
10. Scale check.
a. Performance check.
(1) Wring appropriate size gage blocks (A2 or A3) together and place on base of test instrument in a vertical
position with the bottom working surface of the gage block making contact with anvil of test instrument.
NOTE
Some series 454 height gages measure from the surface
plate instead of the anvil base.
(2) Mount scriber on top side of slide arm and hold in position with accessory clamp and locking screw.
(3) Place test instrument vertically on the surface plate (A1) and position the slide to allow the bottom of the
scriber to almost make contact with the top working surface of the gage block stack.
(4) Tighten locking screw on the fine adjustment clamp. Make final adjustment with knurled nut on the file
adjusting screw, moving the scriber down until contact with the gage block is made. The reading obtained on the
test instrument should equal total length of gage block stack.
(5) Calibrate test instrument at each end of main scale and quarter, half, and three-quarter scale positions.
b. Adjustments.
(1) Loosen screws which fasten vernier plate to slide assembly.
(2) Reposition vernier plate to position which best compensates for errors at zero midscale and full scale.
(3) Tighten screws to secure vernier plate.
11. Final procedure.
a. Install protective covers on test instrument if necessary.
b. In accordance with TM 38-750, annotate and affix DA Label 80 (US Army Calibration Systems). When the test
instrument cannot be adjusted within tolerance, annotate and affix DA Form 2417 (Unserviceable Test Instrument or
Standard) (red tag).
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