TB 9-5210-210-24
8. Dial Accuracy
a. Performance Check
(1) Adjust mounting control on dial indicator calibrator to ensure that contact point
of TI is slightly above plunger on dial indicator calibrator.
(2) Adjust dial indicator calibrator to obtain a zero indication on the black scale.
(3) Adjust mounting control until the contact point makes contact with plunger on
dial indicator calibrator.
(4) Set the TI to zero by rotating the bezel.
(5) Adjust dial indicator calibrator until the equivalent first-numbered division
(inward deflection) on the TI is obtained on the dial indicator calibrator.
NOTE
If the TI has been graduated in millimeter divisions rather
than inches, convert the millimeter-numbered division to
inches and set dial indicator calibrator accordingly.
(25.4 mm = 1 in.)
(6) The TI should indicate within the limits specified in table 1.
(7) Repeat (5) and (6) above at each numbered division within the range of the TI.
(8) Repeat (5) through (7) above at each numbered division on the TI in an
outward deflection.
NOTE
Advance dial indicator calibrator slightly past last observed
reading and then change direction to last observed reading;
this will take up any backlash in calibrator.
NOTE
To calibrate a TI that has a range greater than 1/2 inch, verify
1/2 of range, then set TI to 0 on the point at 1/2 range and
repeat check at each numbered division.
b. Adjustments. No adjustment can be made.
9. Repetition
a. Performance Check
(1) Set the dial indicator calibrator to obtain 25 percent of range indication on the TI.
(2) Move the TI contact point a distance equal to approximately 20 percent of the
range of the TI away from the dial indicator calibrator plunger and allow contact point to
gently return to the plunger.
(3) Repeat (1) and (2) above at least 5 times. The maximum deviation between the
readings observed on the TI shall not exceed 1/5 graduation.
