TB 9-5210-205-50
(2) If the calibration data accumulated for a period of at least 1 year reveals that
the stability criteria is satisfied, the gage block will be sealed as outlined in this bulletin. If
stability criteria is not established, or sufficient data is not available, the gage block will
not be sealed.
NOTE
Gage blocks that are reserved for use as reference standards
for calibration of other gage blocks need not be sealed.
7. Preliminary Instructions
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 name.
8. Equipment Setup
a. Clean the TI, using light duty cycle of an ultrasonic cleaner. Place a beaker of
alcohol or mineral spirits into an energized tank of water. Wait approximately 5 minutes
and insert TI into beaker. If necessary, use a soft brush to remove dirt, grime, or grease. If
ultrasonic cleaner is not available, use the alternate in paragraph b below.
b. Clean TI with solvent and wipe dry with a soft polishing cloth.
Use brush for
cleaning holes in square TI.
d. Clean TI with alcohol or mineral spirits and place on polishing cloth in a wooden tray.
e. Clean inside of TI case.
f. Check for residual magnetism by holding each TI near a suspended, very light piece
of steel with low permeability.
g. Demagnetize if residual magnetism is perceptible, using demagnetizer.
h. Visually inspect each TI for scratches, burrs, nicks, and other surface defects.
i. If necessary, slide the wringing surfaces of each TI across a deburring plate,
applying light pressure to shear off any large burrs that may be present.
j.
Small burrs may be removed by using a deburring stone.
k. Clean TI with alcohol or mineral spirits, wipe dry, and place on cloth in wooden tray.
l. To ensure good wringing quality completely remove burrs. Questionable blocks may
be tested for ringing quality by barely wetting the surface in question with oil and ringing it
to a known good block from the TI set.
m. Allow gage blocks to normalize at a controlled room temperature of 68F (20C) for
at least 8 hours with an additional 1 hour per inch for gage blocks larger than 1 inch.
