TB 9-5220-216-24
8. Thickness
a. Performance Check
NOTE
approximate centers of the test points to be taken within the
critical measurement area. Some readings should be taken at
the leading and side edges in the critical measurement area.
Some of these test points may overlap, due to the size of the
anvil and spindle of the micrometer. Do not position the anvil
in the center section of the headspace gage or past the first
inch of the timing gages.
NOTE
The beveled edges on the headspace gage and wear limit
"NO GO" may not be uniform. The anvil and spindle of
micrometer must both be positioned on the parallel, flat critical
measurement area of the gage and not located in the beveled
section of the gage.
(1) Position the GO section of TI Headspace gage so that one of the test points in the
critical measurement area (fig. 1) is flat against the anvil of the zeroed standard.
(2) Slowly adjust thimble on standard clockwise until the spindle comes in contact with
the TI's critical area. Continue turning thimble clockwise until thimble begins to spin freely.
(3) Standard must indicate within limits in table 3. If not, perform b below.
(4) Record reading on worksheet (Appendix A, fig. A-4 or fig. A-5)) for use in step (7)
below.
NOTE
If any single reading is found to be out of the dimension limits
listed in table 3, the single out of tolerance reading will be
annotated in the ACTUAL GAGE DIMENSIONS section of
DA Form 3023. The averages from worksheet (fig. A-4 or
fig. A-5) will not be used.
(5) Turn standard's thimble counter-clockwise to loosen and move TI to measure
another section (separate measurement point) in the critical measurement area.
(6) Repeat steps (1) through (5) above until the appropriate number of readings have
been taken. Take 9 readings on headspace gage (fig. 1) in each critical measurement areas
NO GO and GO, and 9 readings on the Wear limit/timing gage (fig. 2) in the critical
measurement area NO GO. Take 6 readings in the critical measurement areas of each
(Appendix A, fig. A-4 or fig. A-5)) for use in step (7) below.
(7) Calculate average reading of each area on worksheet (Appendix A, fig. A-4 or
fig. A-5) and annotate results on the DA Form 3023 in the ACTUAL GAGE DIMENSIONS
section.