752 
EhiGals 
The rubber washers should fit snugly into the cavity provided for them. 
After a washer has been used for some time it tends to swell. This leads 
to improper functioning of the gauge and is not desirable. Only washers in 
good condition should be used, 
The small springs tend to lose their elasticity after a time and become 
ineffective. It is important that resilient springs be used. 
3. Arrange the items in rows as follows: 
Farthest from the gauge operator, line up the bases. The studs should 
stick up in the air. Slip the spacer rings over the base; friction will 
hold them in place. In the next row, place the heads, The internal por- 
tions of the heads should be exposed, Make sure that the numbers on the 
various pieces correspond, 
The third row should consist of the pistons, These may best be arranged 
with the larger surfaces dovm., Again make sure that the piston numbers cor-— 
respond to the other picces,. 
The fourth row should consist of the springs. 
The fifth row should consist of the rubber washers, This row is nearest 
the gauge operator. 
Finally, in each washer place one of the measured copper balls, making 
sure that the washer fits around a diametric planc. 
Now, place the springs from the fourth row on the pistons in the third 
row. Invert these two pieces as a unit, and insert them in the head picces 
in the second row. 
At this stage, one has left only three rows of materials. 
Next, insert the rubber washer and the copper ball as a unit into the 
head piece. Make sure that the washer fits snugly into the cavity, and 
that the piston slides freely in the head, 
The last step consists of screwing this complete head assembly onto the 
base assembly; that is, combining the elements in the farthest two rows, 
When the final assembly of the head has been made, and it is being 
screwed onto the basc, the ball and washer unit should not be permitted to 
become loose. 
h. The completely assembled gauge should be checked by pressing on the 
piston. If the spring and washer are in proper condition, no play should be 
observed, If any play is observed the gauge as assembled is unsatisfactory 
and may give a deformation that corresponds to a higher pressure than actual— 
ly existed in the shock wave. It should be reassembled using a spring or 
washer in good condition. 
Cleaning the gauge: All parts of the gauge should be carefully cleaned after 
each usee The parts made of stecl shovld be immersed in oil to prevent cor- 
rosion. Remove all oil before assembling the gauge for re=usce 
