Changing Wire Feed Rolls And Guide Tubes For 4-Roll Wire Feeders; Setting The Idler Roll Pressure (4-Roll Wire Drives - Lincoln Electric LN-9 SVM127-A Service Manual

B-11
CHANGING WIRE FEED ROLLS AND
GUIDE TUBES FOR 4-ROLL WIRE FEED-
ERS
To change drive rolls on a 4-roll wire feeder, refer to
Figure B.4 and perform the following steps:
1. Release both quick release levers.
2. Remove clamping collars from both drive shafts.
3. Install one drive roll and replace clamping collar.
Tighten screw.
4. Slide the middle guide tube into place. Do not
tighten set screw.
5. Install second drive roll and replace clamping col-
lar. Tighten screw. (Note: The middle guide tube
may need to be pushed up tight against the first
drive roll to allow room for installing the second
roll.)
6. Center the middle guide tube and lock in place with
its set screw.
7. Remove the idle roll quick release pins - install idle
rolls. Replace pins.
NOTE: The aluminum wire drive roll kits have one-
piece drive rolls and idle rolls with a larger chamfer
on one side, instead of gear teeth. This larger
chamfer side must face the gearbox when
installed. The side with the smaller chamfer and
wire size stencil must be installed facing out.
8. Loosen the ingoing guide tube clamping screw.
Install the all steel guide tube. The guide tube
should be slid in until it almost touches the drive
rolls. Tighten the locking screw.
9. Install the outgoing guide tube with its plastic insert
through the front brass block. Tighten the locking
screw so its dog point goes into the groove in the
O.D. of the guide tube.
NOTE: The drive rolls and guide tubes are
stamped with the wire size ranges (in inches and
mm) for which they are designed. If a wire size
other than that stamped is to be used, the drive
rolls and guide tubes will have to be changed.
Drive rolls stamped with a "(C)" suffix to the wire
size range are recommended specifically for use
with cored wires.
OPERATION
SETTING THE IDLER ROLL PRESSURE (4-ROLL
WIRE DRIVES)
Because every feeding situation is different, the
4-roll wire drive does not have graduated markings
with wire sizes indicated on it. A recommended
starting pressure is indicated below for each
applicable wire size and type. Depending on the
particular application, these starting pressures may
need to be adjusted up or down. Some of the vari-
ables that affect tension settings are type and
brand of electrode, surface condition, lubrication,
harness, type and length of cables and conduits,
routings of cables and conduits, and drive roll
wear.
In most applications, the front and rear drive roll
pressures should be adjusted the same. To adjust,
start by releasing both "quick release" arms.
Tighten the tension adjusting screws to full pres-
sure and then back off per the particular instruc-
tions for your electrode size and type as outlined
below.
For Steel Wire
1. .030-.052" solid-----------4 turns from maximum
.045-.052" cored--------12 turns from maximum
The optimum pressure setting can be determined
when there are wire stoppages.
"birdnests" between the rolls and guide tubes, the
pressure is too great. When properly set, during a
stoppage the drive rolls will slip. If the electrode is
removed from the cable there will be a slight wavi-
ness in the electrode for about a foot beyond the
slip marks on the electrode. If there is no wavi-
ness, the pressure is too low.
2. 1/16" solid-----------2 to 4 turns from maximum
.062" cored----------7 to 8 turns from maximum
These settings should be accurate unless the elec-
trode is unusually soft or the feeding path is exces-
sively long or curved.
3. .068-3/32" solid----8 to 10 turns from maximum
.068-.120" cored----6 or 7 turns from maximum
Larger wire settings are accurate for nearly all
applications.
require "fine tuning."
LN-9 Wire Feeder
If the wire
Some unusual circumstances will
B-11