17
4.6.3 WIRE FEEDER MECHANISM
4.6.3.1 DRIVE ROLLS (FIGURE 4-5)
The drive roll has two grooves: the small groove feeds
0.035 in. diameter wire, the large groove feeds 0.045
in. wire. The groove nearest the gear motor feeds the
wire. If the required groove is not correctly positioned,
perform the following:
A. Release the pressure drive roll lever and lift the
assembly upward.
B. Remove the two (2) screws holding the drive
roll to the gear.
C. Reverse the drive roll on the drive roll shaft.
D. Replace the screws and tighten.
E. Secure the pressure drive roll assembly.
Figure 4-5. Wire Feeder Mechanism
4.6.3.2 WELDING WIRE SPOOL
AS WITH ANY WORK AREA, MAKE SURE SAFETY
GLASSES WITH SIDE SHIELDS ARE WORN WHEN
HANDLING OR CHANGING WIRE OR CLIPPING
WIRE OFF AT THE SPOOL OR AT THE END OF THE
TORCH. HOLD ONTO THE WIRE COMING OFF THE
SPOOL WITH ONE HAND BEFORE CLIPPING. SE-
RIOUS EYE INJURY CAN RESULT DUE TO THE RE-
SILIENCE OF THE WIRE WHICH CAN QUICKLY UN-
RAVEL, OR A CUT WIRE END WHICH MAY SHOOT
ACROSS THE ROOM.
Install a spool of welding wire on the hub as follows:
A. Unscrew spool nut from hub.
B. Place wire spool on hub to rotate clockwise as
wire is unwound; hub pin must engage hole in
spool.
C. Install spool nut.
4.6.3.3 THREADING WELDING WIRE
A. Turn off power switch.
WHEN THE POWER SWITCH IS ON, AND GUN
TRIGGER IS DEPRESSED, THE ELECTRODE WIRE
BECOMES ELECTRICALLY HOT, AND THE WIRE
FEED ROLLS ARE ACTIVATED.
B. Release pressure drive roll assembly and lift
upward. Check that proper wire diameter
groove is in the inner position.
Before threading welding wire through liner, make
sure chisel point and burrs have been removed
from wire end to prevent wire from jamming in gun
or liner.
C. Feed the wire from the spool through the inlet
guide, across the drive roll groove and into gun
outlet guide.
Make sure that the proper "outlet guide tube" is inserted
into the front-panel gun fitting for the size and type of
wire being used, see Table 2-3 for wire feed accesso-
ries.
To ensure proper wire feeding, it is important that the
wire be kept clean and that the drive rolls be periodi-
cally cleaned of any chips or scale that might be car-
ried into the gun liner and cause sticking.
D. Lower pressure roll assembly and secure.
Check that the gears mesh. Feed wire through
to gun tip using the inch/purge switch.
4.6.3.4 BRAKE DRAG ADJUSTMENT
Brake disc friction should provide enough drag to keep
the wire spool or core from spinning freely after wire
feed stops. If adjustment is required, turn adjusting
screw clockwise to increase drag, counterclockwise to
decrease it. Drag should be just low enough to limit
wire overrun.
