TB 9-5210-221-40
Table 2. Minimum Specifications of Equipment Required
Manufacturer and model
Common name
Minimum use specifications
(part number)
GAGE BLOCK SET
Range: 0.050 to 4 in.
(7901961)
Accuracy: 0.00125 in.
SURFACE PLATE
Accuracy: 0.0001 in.
18" x 24" (7900123)
Grade AA
6. Preliminary Instructions
a. The instructions outlined in paragraphs 6 and 7 are preparatory to the calibration
process. Personnel should become familiar with the entire bulletin before beginning the
calibration.
b. Items of equipment used in this procedure are referenced within the text by common
c. Unless otherwise specified, verify the result of each test and, whenever the test
requirement is not met, take corrective action before continuing with the calibration.
Adjustments required to calibrate the TI are included in this procedure. Additional
maintenance information is contained in the manufacturer's manual for this TI.
d. Unless otherwise specified, all controls and control settings refer to the TI.
a. Allow TI and test equipment 4 hours to stabilize at ambient temperature.
b. Inspect TI top and bottom reference surfaces for defects and cleanliness. Repair and
clean as necessary.
c. Use precision level to level surface plate within 30 sec-arc along length and width of
surface plate.
a. Performance Check
NOTE
Allow bubble to settle 15 seconds before taking a reading.
NOTE
Make certain no one is propping or leaning on the surface plate.
(1) Place TI on surface plate and against a parallel bar that has been clamped to the
clamping ledge of the surface plate; this will ensure repeatable observations.
(2) Note the reading, and rotate the TI 180 degrees.