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APPENDIX IV 
Use of 'the Improved Hilliar Gauge 
[Adapted from Navy Department, 
Buord (Re2c) Technical Note No. 15.] 
Arrangement of the gauge: The gauge, when ready for operation, consists of 
the following pieces: 
1. The body of the gauge, which is used as a housing for most of the 
other pieccs. 
2. A cap for the gauge. 
3. Six anvils, numbered 1 through 6, 
lh. Seven pistons, numbered O through 6, and corresponding springs. 
5 One small retaining plate with three holes. 
6. One sheet of cellophane. 
7e One rubber gasket. 
8. One ridge ee slots to fit pins on the body of the gauge. 
9. One threaded clamp ring designed to hold the ridge ring. 
10, Six copper cylinders, 0.500 in. long, and one copper ball 0.375 in. 
in diameter, : 
11. One rubber centering washer for copper ball. 
Preparing the gauge for use: 
1. Copper pellets and spheres should be selected from lots of uniform 
hardness and diameter, The length of each individual pellet should be re- 
corded to 0.0001 in. The diameter of cach sphere should be recorded to 
0.0001 in., and the out-of-roundness should not exceed + 0,0003 in. 
2. Determine the number of gauges to be used in the test. Secure 
sufficient parts, as described above, to constitute that number of gauges. 
Be sure all parts of the same gauge bear the same serial number, 
Check that all pistons travel freely in the gauge. 
Since the cellophane disk serves as the waterproof seal for the bottom 
of the gauge its preparation is important. This disk should be cut with 
the cutter (biscuit type) designod especially for this purpose. Scissors 
should never be used to trim cellophane to size as this is likely to produce 
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