TB 9-5210-216-24
d. If necessary, clean thimble and spindle and apply a small quantity of instrument oil.
8. Zero Check
a. Performance Check
(1) For TI's range of 0 to 1 inch, check zero by adjusting TI thimble until a light,
firm contact is made between spindle and anvil. If indication on barrel is not zero, perform
b below.
(2) For TI's greater than 1 inch, check zero by positioning setting standard (supplied
with TI) between spindle and anvil of TI until a light, firm contact is made with the
standard. If indication on barrel is not zero, perform b below.
b. Adjustments
(1) Rotate thimble until measuring face of anvil and spindle come together, or make
contact with appropriate setting standard.
(2) Adjustment procedures vary with manufacturer.
Adjust in accordance with
manufacturer's manual (R).
9. Pitch Diameter Indication
a. Performance Check
NOTE
To calibrate a TI graduated in the metric system, it will be
necessary to convert the metric reading to applicable length in
inches. Formula is: 1 millimeter = 0.03937 inch, or 1 inch =
25.4 millimeters.
(1) Select the appropriate thread plug gage from table 2 that is within the pitch
range of the TI.
(2) Adjust the TI micrometer as necessary to position the thread plug gage between
the TI spindle and anvil as shown in figure 1 below, so that as the TI is slowly moved across
the pitch diameter of the thread plug gage; a slight drag is noticed.
Figure 1. Thread gage position.
