(c) Tube-to-tube connections. To make a
tube-to-tube connection, the tube B-nut is tightened until
a definite resistance is felt and is then turned one-sixth
of a turn farther. The upper wrench is held stationary
while the lower wrench is moved upward until the B-nut
is tightened a sufficient amount (see figure 4-22). On
this tube connection, like most others, a 1/8-inch colored
stripe may be painted across the completed assembly
so that loosening can be readily detected (see figure
(4) Bulkhead fitting installation. These fittings
are used for connecting tubing to components of the
system, and for connecting sections of tubing where the
line passes through a bulkhead and the fitting is secured
to the bulkhead, as shown in figure 4-24. Refer to table
4-4 for the correct fitting size.
(a) Hand presetting of MS21922 sleeve.
The MS21922 sleeve can be preset using the following
1 Bottom the tube end firmly In the seat of
the preset tool or fitting.
2 TightentheMS21921 nut1 1/6 turns past
the point of ring grip on all sizes and materials for all
types of fittings or tubes.
Figure 4-19. MS Fitting Gasket Installation
(b) Resetting (Installation). Tighten the
MS21921 nut in accordance with table 4-5.
(c) Boss installation of MS33514 fitting end,
style E. This fitting can be Installed as follows
1 Lubricate the packing in appropriate lie-
id (refer to table 4-6).
2 Install packing on the fitting as shown In
detail A, figure 4-25
3 Screw the fitting assembly into the boss
using installation torque In accordance with table 4-7
(d) Installation of AN 924 jamnut. Torque
values can be found In table 4-8.
b. Oxygen System Tapered Pipe Thread.
Tapered pipe thread fittings are a versatile and efficient
method of connecting tubing to components.
(1) Tubing fittings tapered pipe threads. Pipe
threads should conform to MIL-P-710-5. Straight thread
and tapered pipe thread are shown In figure 4-26.
When installing pipe thread fittings, fittings
should be tightened but not enough to
damage threads or crack the part In which
fitting is being Installed.
Figure 4-20. Tubing Alignment