2-2. Operation of Equipment
b. Starting. Refer to TM 5-3431-221-15 for
starting instructions.
a. General.
(1) The instructions in this paragraph are for
c. Stopping. Refer to TM 5-3431-221-15 for
the information and guidance of personnel
stopping instructions.
responsible for operation of the welding shop.
d. Operation of "MIG" Welding Gun (fig. 2-3).
(2) The operator must know how to perform
(1) Guide tube position. Loosen the thumb-
every operation of which the welding shop is
screw (1) and adjust the position of the guide tube
capable. This paragraph contains instructions on
until the end of the guide tube is
in. behind the
edge of the nozzle (9). When using 0.030 and 0.047
starting and stopping the welding shop, on
inch wires, the rear end of the guide tube must be
operation of the welding shop, and on coordinating
the basic motions to perform the specific tasks for
back against the front guide tube bushing to
prevent the wire from buckling, with the rear end of
which the equipment is designed. Since nearly
an 0.030 or 0.047 inch guide tube (in the SP-10
every job presents a different problem, the operator
may have to vary given procedures to fit the in-
gun) positioned against the guide bushing, the front
end will be just even or slightly in front of the
dividual job.
nozzle.
slipping. Excessive pressure will overload the motor
(2) Wire threading. Unscrew the knurled
and cause erratic welding action. Too little pressure
spool cover bolt, and remove the plastic cover. Pull
will allow slippage and cause "burn backs". Switch
back the adjustable brake (2) and place the desired
the welder on and pull the gun trigger (8). Since
spool of welding wire on the spool shaft so that the
welding power will be on when the trigger is pulled
free end of the wire will pay-off from the top of the
make sure the electrode does not touch the worn
spool into the rear guide bushing (3). Loosen the
ground as an arc will result. If the wire has been.
wire pressure screw (4) and open the swing arm
threaded properly and the pressure screw is ad-
(5). Thread the free end of the wire into the rear
justed for the correct pressure, the wire will feed
guide bushing, through the front guide bushing (6)
freely from the guide tube.
and into the wire guide tube (7). Close the swing
(3) Brake adjustment. Loosen the two screws
arm (5) and adjust the pressure screw until there is
which hold the brake support. Adjust the position
just sufficient pressure to prevent the wire from
