TB 9-5210-205-40
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.
c. Discard all blocks containing pits that might prevent accurate calibration.
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 wringing quality by barely wetting the surface in question with oil and
wringing 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.
9. Calibration for Flatness
a. Performance Check
NOTE
Handle blocks with gloves or forceps.
(1) Test the wringing surfaces of TI for flatness, as follows:
(a) Place TI on the platen of the interferometer and adjust until the desired
fringe pattern appears (B, fig.1)
(b) Arrange the fringes to appear first in one direction on TI and then the other.
