Lincoln Electric LF-72 User manual

Operator’s Manual
LF-72 WIRE FEEDER
Register your machine:
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Authorized Service and Distributor Locator:
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IM10258 | Issue Date Apr-15
© Lincoln Global, Inc. All Rights Reserved.
For use with machines having Code Numbers:
12454
Save for future reference
Date Purchased
Code: (ex: 10859)
Serial: (ex: U1060512345)

THANK YOU FOR SELECTING
A QUALITY PRODUCT BY
LINCOLN ELECTRIC.
PLEASE EXAMINE CARTON AND EQUIPMENT FOR
DAMAGE IMMEDIATELY
When this equipment is shipped, title passes to the purchaser
upon receipt by the carrier. Consequently, claims for material
damaged in shipment must be made by the purchaser against the
transportation company at the time the shipment is received.
SAFETY DEPENDS ON YOU
Lincoln arc welding and cutting equipment is designed and built
with safety in mind. However, your overall safety can be increased
by proper installation ... and thoughtful operation on your part.
DO NOT INSTALL, OPERATE OR REPAIR THIS EQUIPMENT
WITHOUT READING THIS MANUAL AND THE SAFETY
PRECAUTIONS CONTAINED THROUGHOUT. And, most importantly,
think before you act and be careful.
This statement appears where the information must be followed
exactly to avoid serious personal injury or loss of life.
This statement appears where the information must be followed
to avoid minor personal injury or damage to this equipment.
KEEP YOUR HEAD OUT OF THE FUMES.
DON’T get too close to the arc.
Use corrective lenses if necessary
to stay a reasonable distance
away from the arc.
READ and obey the Safety Data
Sheet (SDS) and the warning label
that appears on all containers of
welding materials.
USE ENOUGH VENTILATION or
exhaust at the arc, or both, to
keep the fumes and gases from
your breathing zone and the general area.
IN A LARGE ROOM OR OUTDOORS, natural ventilation may be
adequate if you keep your head out of the fumes (See below).
USE NATURAL DRAFTS or fans to keep the fumes away
from your face.
If you develop unusual symptoms, see your supervisor.
Perhaps the welding atmosphere and ventilation system
should be checked.
WEAR CORRECT EYE, EAR &
BODY PROTECTION
PROTECT your eyes and face with welding helmet
properly fitted and with proper grade of filter plate
(See ANSI Z49.1).
PROTECT your body from welding spatter and arc
flash with protective clothing including woolen
clothing, flame-proof apron and gloves, leather
leggings, and high boots.
PROTECT others from splatter, flash, and glare
with protective screens or barriers.
IN SOME AREAS, protection from noise may be appropriate.
BE SURE protective equipment is in good condition.
Also, wear safety glasses in work area
AT ALL TIMES.
SPECIAL SITUATIONS
DO NOT WELD OR CUT containers or materials which previously
had been in contact with hazardous substances unless they are
properly cleaned. This is extremely dangerous.
DO NOT WELD OR CUT painted or plated parts unless special
precautions with ventilation have been taken. They can release
highly toxic fumes or gases.
Additional precautionary measures
PROTECT compressed gas cylinders from excessive heat,
mechanical shocks, and arcs; fasten cylinders so they cannot fall.
BE SURE cylinders are never grounded or part of an
electrical circuit.
REMOVE all potential fire hazards from welding area.
ALWAYS HAVE FIRE FIGHTING EQUIPMENT READY FOR
IMMEDIATE USE AND KNOW HOW TO USE IT.
WARNING
CAUTION
Safety 01 of 04 - 5/16/2018

SECTION A:
WARNINGS
CALIFORNIA PROPOSITION 65 WARNINGS
WARNING: Breathing diesel engine exhaust
exposes you to chemicals known to the State
of California to cause cancer and birth defects,
or other reproductive harm.
• Always start and operate the engine in a
well-ventilated area.
• If in an exposed area, vent the exhaust to the outside.
• Do not modify or tamper with the exhaust system.
• Do not idle the engine except as necessary.
For more information go to
www.P65 warnings.ca.gov/diesel
WARNING: This product, when used for welding or
cutting, produces fumes or gases which contain
chemicals known to the State of California to cause
birth defects and, in some cases, cancer. (California
Health & Safety Code § 25249.5 et seq.)
WARNING: Cancer and Reproductive Harm
www.P65warnings.ca.gov
ARC WELDING CAN BE HAZARDOUS. PROTECT
YOURSELF AND OTHERS FROM POSSIBLE SERIOUS
INJURY OR DEATH. KEEP CHILDREN AWAY.
PACEMAKER WEARERS SHOULD CONSULT WITH
THEIR DOCTOR BEFORE OPERATING.
Read and understand the following safety highlights. For
additional safety information, it is strongly recommended
that you purchase a copy of “Safety in Welding & Cutting -
ANSI Standard Z49.1” from the American Welding Society,
P.O. Box 351040, Miami, Florida 33135 or CSA Standard
W117.2-1974. A Free copy of “Arc Welding Safety” booklet
E205 is available from the Lincoln Electric Company,
22801 St. Clair Avenue, Cleveland, Ohio 44117-1199.
BE SURE THAT ALL INSTALLATION, OPERATION,
MAINTENANCE AND REPAIR PROCEDURES ARE
PERFORMED ONLY BY QUALIFIED INDIVIDUALS.
FOR ENGINE POWERED
EQUIPMENT.
1.a. Turn the engine off before troubleshooting
and maintenance work unless the
maintenance work requires it to be running.
1.b. Operate engines in open, well-ventilated areas or vent the engine
exhaust fumes outdoors.
1.c. Do not add the fuel near an open flame welding
arc or when the engine is running. Stop the
engine and allow it to cool before refueling to
prevent spilled fuel from vaporizing on contact
with hot engine parts and igniting. Do not spill fuel when filling
tank. If fuel is spilled, wipe it up and do not start engine until
fumes have been eliminated.
1.d. Keep all equipment safety guards, covers
and devices in position and in good repair.
Keep hands, hair, clothing and tools away
from V-belts, gears, fans and all other
moving parts when starting, operating or
repairing equipment.
1.e. In some cases it may be necessary to remove safety guards to
perform required maintenance. Remove guards only when
necessary and replace them when the maintenance requiring
their removal is complete. Always use the greatest care when
working near moving parts.
1.f. Do not put your hands near the engine fan. Do not attempt to
override the governor or idler by pushing on the throttle control
rods while the engine is running.
1.g. To prevent accidentally starting gasoline engines while turning
the engine or welding generator during maintenance work,
disconnect the spark plug wires, distributor cap or magneto wire
as appropriate.
1.h. To avoid scalding, do not remove the radiator
pressure cap when the engine is hot.
ELECTRIC AND
MAGNETIC FIELDS MAY
BE DANGEROUS
2.a. Electric current flowing through any conductor
causes localized Electric and Magnetic Fields (EMF).
Welding current creates EMF fields around welding cables
and welding machines
2.b. EMF fields may interfere with some pacemakers, and
welders having a pacemaker should consult their physician
before welding.
2.c. Exposure to EMF fields in welding may have other health effects
which are now not known.
2.d. All welders should use the following procedures in order to
minimize exposure to EMF fields from the welding circuit:
2.d.1. Route the electrode and work cables together - Secure
them with tape when possible.
2.d.2. Never coil the electrode lead around your body.
2.d.3. Do not place your body between the electrode and work
cables. If the electrode cable is on your right side, the
work cable should also be on your right side.
2.d.4. Connect the work cable to the workpiece as close as pos-
sible to the area being welded.
2.d.5. Do not work next to welding power source.
SAFETY
Safety 02 of 04 - 5/16/2018

ELECTRIC SHOCK
CAN KILL.
3.a. The electrode and work (or ground) circuits are
electrically “hot” when the welder is on. Do
not touch these “hot” parts with your bare skin or wet clothing.
Wear dry, hole-free gloves to insulate hands.
3.b. Insulate yourself from work and ground using dry insulation.
Make certain the insulation is large enough to cover your full area
of physical contact with work and ground.
In addition to the normal safety precautions, if
welding must be performed under electrically
hazardous conditions (in damp locations or while
wearing wet clothing; on metal structures such as
floors, gratings or scaffolds; when in cramped
positions such as sitting, kneeling or lying, if there
is a high risk of unavoidable or accidental contact
with the workpiece or ground) use the following
equipment:
• Semiautomatic DC Constant Voltage (Wire) Welder.
• DC Manual (Stick) Welder.
• AC Welder with Reduced Voltage Control.
3.c. In semiautomatic or automatic wire welding, the electrode,
electrode reel, welding head, nozzle or semiautomatic welding
gun are also electrically “hot”.
3.d. Always be sure the work cable makes a good electrical
connection with the metal being welded. The connection should
be as close as possible to the area being welded.
3.e. Ground the work or metal to be welded to a good electrical (earth)
ground.
3.f. Maintain the electrode holder, work clamp, welding cable and
welding machine in good, safe operating condition. Replace
damaged insulation.
3.g. Never dip the electrode in water for cooling.
3.h. Never simultaneously touch electrically “hot” parts of electrode
holders connected to two welders because voltage
between the
two can be the total of the open circuit voltage of both
welders.
3.i. When working above floor level, use a safety belt to protect
yourself from a fall should you get a shock.
3.j. Also see Items 6.c. and 8.
ARC RAYS CAN BURN.
4.a. Use a shield with the proper filter and cover plates to protect your
eyes from sparks and the rays of the arc when welding or
observing open arc welding. Headshield and filter lens should
conform to ANSI Z87. I standards.
4.b. Use suitable clothing made from durable flame-resistant material
to protect your skin and that of your helpers from the arc rays.
4.c. Protect other nearby personnel with suitable, non-flammable
screening and/or warn them not to watch the arc nor expose
themselves to the arc rays or to hot spatter or metal.
FUMES AND GASES
CAN BE DANGEROUS.
5.a. Welding may produce fumes and gases
hazardous to health. Avoid breathing these
fumes and gases. When welding, keep your head out of the fume.
Use enough ventilation and/or exhaust at the arc to keep fumes
and gases away from the breathing zone. When welding
hardfacing (see instructions on container or SDS)
or on lead or cadmium plated steel and other
metals or coatings which produce highly toxic
fumes, keep exposure as low as possible and
within applicable OSHA PEL and ACGIH TLV limits
using local exhaust or mechanical ventilation
unless exposure assessments indicate otherwise.
In confined spaces or in some circumstances,
outdoors, a respirator may also be required.
Additional precautions are also required when
welding
on galvanized steel.
5. b. The operation of welding fume control equipment is affected by
various factors including proper use and positioning of the
equipment, maintenance of the equipment and the specific
welding procedure and application involved. Worker exposure
level should be checked upon installation and periodically
thereafter to be certain it is within applicable OSHA PEL and
ACGIH TLV limits.
5.c. Do not weld in locations near chlorinated hydrocarbon vapors
coming from degreasing, cleaning or spraying operations. The
heat and rays of the arc can react with solvent vapors to form
phosgene, a highly toxic gas, and other irritating products.
5.d. Shielding gases used for arc welding can displace air and
cause
injury or death. Always use enough ventilation, especially in
confined areas, to insure breathing air is safe.
5.e. Read and understand the manufacturer’s instructions for this
equipment and the consumables to be used, including the
Safety Data Sheet (SDS) and follow your employer’s safety
practices. SDS forms are available from your welding
distributor or from the manufacturer.
5.f. Also see item 1.b.
SAFETY
Safety 03 of 04 - 5/16/2018

WELDING AND CUTTING
SPARKS CAN CAUSE
FIRE OR EXPLOSION.
6.a. Remove fire hazards from the welding area. If
this is not possible, cover them to prevent the welding sparks
from starting a fire. Remember that welding sparks and hot
materials from welding can easily go through small cracks and
openings to adjacent areas. Avoid welding near hydraulic lines.
Have a fire extinguisher readily available.
6.b. Where compressed gases are to be used at the job site, special
precautions should be used to prevent hazardous situations.
Refer to “Safety in Welding and Cutting” (ANSI Standard Z49.1)
and the operating information for the equipment being used.
6.c. When not welding, make certain no part of the electrode circuit is
touching the work or ground. Accidental contact can cause
overheating and create a fire hazard.
6.d. Do not heat, cut or weld tanks, drums or containers until the
proper steps have been taken to insure that such procedures
will not cause flammable or toxic vapors from substances inside.
They can cause an explosion even though they have been
“cleaned”. For information, purchase “Recommended Safe
Practices for the Preparation for Welding and Cutting of
Containers and Piping That Have Held Hazardous Substances”,
AWS F4.1 from the American Welding Society
(see address above).
6.e. Vent hollow castings or containers before heating, cutting or
welding. They may explode.
6.f. Sparks and spatter are thrown from the welding arc. Wear oil free
protective garments such as leather gloves, heavy shirt, cuffless
trousers, high shoes and a cap over your hair. Wear ear plugs
when welding out of position or in confined places. Always wear
safety glasses with side shields when in a welding area.
6.g. Connect the work cable to the work as close to the welding area
as practical. Work cables connected to the building framework or
other locations away from the welding area increase the
possibility of the welding current passing through lifting chains,
crane cables or other alternate circuits. This can create fire
hazards or overheat lifting chains or cables until they fail.
6.h. Also see item 1.c.
6.I. Read and follow NFPA 51B “Standard for Fire Prevention During
Welding, Cutting and Other Hot Work”, available from NFPA, 1
Batterymarch Park, PO box 9101, Quincy, MA 022690-9101.
6.j. Do not use a welding power source for pipe thawing.
CYLINDER MAY EXPLODE IF
DAMAGED.
7.a. Use only compressed gas cylinders containing
the correct shielding gas for the process used
and properly operating regulators designed for
the gas and pressure used. All hoses, fittings,
etc. should be suitable for the application and
maintained in good condition.
7.b. Always keep cylinders in an upright position securely chained to
an undercarriage or fixed support.
7.c. Cylinders should be located:
• Away from areas where they may be struck or subjected
to physical damage.
• A safe distance from arc welding or cutting operations
and any other source of heat, sparks, or flame.
7.d. Never allow the electrode, electrode holder or any other
electrically “hot” parts to touch a cylinder.
7.e. Keep your head and face away from the cylinder valve outlet
when opening the cylinder valve.
7.f. Valve protection caps should always be in place and hand tight
except when the cylinder is in use or connected for use.
7.g. Read and follow the instructions on compressed gas cylinders,
associated equipment, and CGA publication P-l, “Precautions for
Safe Handling of Compressed Gases in Cylinders,” available from
the Compressed Gas Association, 14501 George Carter Way
Chantilly, VA 20151.
FOR ELECTRICALLY
POWERED EQUIPMENT.
8.a. Turn off input power using the disconnect
switch at the fuse box before working on
the equipment.
8.b. Install equipment in accordance with the U.S. National Electrical
Code, all local codes and the manufacturer’s recommendations.
8.c. Ground the equipment in accordance with the U.S. National
Electrical Code and the manufacturer’s recommendations.
Refer to
http://www.lincolnelectric.com/safety
for additional safety information.
SAFETY
Safety 04 of 04 - 5/16/2018

vi
vi TABLE OF CONTENTS
Page
Installation.............................................................................................................Section A
Technical Specifications ..............................................................................................A-1
Safety Precautions .......................................................................................................A-2
Location...................................................................................................................A-2
Mounting ..................................................................................................................A-2
Bench Mount............................................................................................................A-3
Swivel Mount ...........................................................................................................A-3
Boom Mount ............................................................................................................A-3
Suspended...............................................................................................................A-3
Weld Cable Sizes .....................................................................................................A-4
Coaxial Weld Cables................................................................................................A-5
Weld Cable Connections .........................................................................................A-5
Analog Control Cable Connections ..............................................................................A-6
Analog Miller Control Cable Adapter............................................................................A-7
Welding Gun/Wire Feeder Trigger Connector.........................................................A-8
High Frequency Protection .....................................................................................A-8
Remote Sense Lead Specifications ........................................................................A-8
Wire Drive Systems ......................................................................................................A-8
Welding Guns, Torches and Accessories ....................................................................A-9
Procedure for Changing Drive and Idle Roll Sets.......................................................A-10
Wire Drive Configuration..............................................................................A-10, A-11
Pressure Arm Adjustment .....................................................................................A-11
Wire Reel Loading .................................................................................................A-12
Weld Wire Routing.................................................................................................A-13
Shielding Gas Connections........................................................................................A-14
Installing Electrode Conduit Kits ................................................................................A-15
Aluminum Wire Preparations......................................................................................A-16
Base Model, Bench Model Standard Duty and Bench Model Heavy Duty................A-17
Typical System Configurations ..................................................................................A-18
__________________________________________________________________________
Operation ..............................................................................................................Section B
Safety Precautions .......................................................................................................B-1
Graphic Symbols..........................................................................................................B-1
Common Welding Abbreviations..................................................................................B-2
Product Description .....................................................................................................B-2
Recommended Processes and Required Equipment ..................................................B-2
Front Panel Controls and Connections ........................................................................B-3
1. Remote Voltage Control Kit (Optional) ................................................................B-4
2. Burnback and Postflow Timer Kit (Optional) .......................................................B-4
3. Thermal LED, Motor Overload.............................................................................B-4
4. Cold Feed/Gas Purge Switch..............................................................................B-4
5. 2 Step - Trigger Interlock Switch.................................................................B-4, B-5
6. Wire Feed Speed Knob .......................................................................................B-5
7. Gun Receiver Bushing.........................................................................................B-5
8. Trigger Connector 5-Pin Amphenol.....................................................................B-5
__________________________________________________________________________
Accessories ..........................................................................................................Section C
General Options and Accessories..................................................................C-1 Thru C4
___________________________________________________________________________________

vii
TABLE OF CONTENTS
LF-72
vii
Page
Maintenance....................................................................................................Section D
Safety Precautions ................................................................................................D-1
Routine Maintenance ............................................................................................D-1
Periodic Maintenance ...........................................................................................D-1
Calibration Specification .......................................................................................D-1
Major Component Locations ................................................................................D-2
________________________________________________________________________
Troubleshooting ..............................................................................................Section E
Safety Precautions ................................................................................................E-1
How To Use Troubleshooting Guide .....................................................................E-1
Troubleshooting Guides.................................................................................E-2, E-3
________________________________________________________________________
Wiring Diagram and Dimension Prints ..........................................................Section F
________________________________________________________________________
Parts List .........................................................................................................................parts.lincolnelectric.com
Content/details may be changed or updated without notice. For most current Instruction Manuals, go to
parts.lincolnelectric.com.
______________________________________________________________________

A-1
INSTALLATION
LF-72
A-1
TECHNICAL SPECIFICATIONS: LF-72 WIRE FEEDER
SPEC.# TYPE WIRE FEED SPEED RANGE
∆Dimensions do not include wire reel.
Wire Size
LF-72 Speed Solid Cored
K2327-9 Bench Model 50-800 IPM .023 - 1/16 in. .035 - 5/64 in
Standard Duty (1.27-20.3 m/m) (0.6 - 1.6 mm) (0.9 - 2.0 mm)
CONTROL BOX, WIRE DRIVE AND COMPLETE UNITS
SPEC.# TYPE INPUT POWER PHYSICAL SIZE• TEMPERATURE RATING
Input Voltage Dimensions
and Current Height Width Depth Weight Operating Storage
K2327-9 LF-72 24-42VAC 12.6“ 10.9“ 22.5“ 52.5 Lbs 14°F to 104°F -40°F to 185°F
Bench 9 AMPS ( 320 mm) (277 mm) (572 mm) (23.8 Kg.) (-10°C to 40°C) ( -40°C to 85°C)
Standard
Duty
WELDING CAPACITY RATING
Amp Rating Duty Cycle
500 A 60%

A-2
INSTALLATION
LF-72
A-2
SAFETY PRECAUTION
LOCATION
The LF-72 may be placed on a bench or mounted on
top of a welding power source.
Place the LF-72 in a clean and dry location.
Do not stack the LF-72.
This equipment is for industrial use only and it is not
intended for use in residential locations where the
electrical power is provided by the public low-voltage
supply system. There can be potential difficulties in
residential locations due to conducted as well as
radiated radio-frequency disturbances. The EMC or
RF classification of this equipment is Class A.
ELECTRIC SHOCK can kill.
• Only qualified personnel should
perform this installation.
• Turn off the input power to the
power source at the disconnect
switch or fuse box before working
on this equipment. Turn off the
input power to any other equip-
ment connected to the welding
system at the disconnect switch or
fuse box before working on this
equipment.
• Do not touch electrically hot parts.
-----------------------------------------------------------------------
FIGURE A.1
FIGURE A.2
MOUNTING
For location and size, LF-72 Bench Model Rear
Mounting Holes (See Figure A.1) and for Bottom
Mounting Holes (See Figure A.2).

A-3
INSTALLATION
LF-72
A-3
BENCH MOUNT
The LF-72 mounts in a variety of configurations. As
shipped from the factory, the LF-72 is suitable for
bench mounting or placing directly on top of the
welding power source (CV-xxx and DC-xxx product
family only).
SWIVEL MOUNT
Both the standard duty bench model and heavy duty
bench model may be mounted onto a swivel when a
top a welding power source.
BOOM MOUNT
When boom mounting, remove the wire reel stand (if
assembled) and secure the wire feeder directly to the
desired surface.
SUSPENDED
Only suspend the wire feeder by the lift bail of the
portability kit.
Alternative methods for hanging the wire feeder
must not be used unless insulation is provided
between the wire feeder enclosure and the
hanging device.
----------------------------------------------------------
Bench Mount
Swivel Kit and Bench Model, Standard Duty
Swivel Kit and Base Model LF-72
WARNING

A-4
INSTALLATION
LF-72
A-4
SAFETY PRECAUTION
ELECTRIC SHOCK can
kill.
• Only qualified personnel should
perform this installation.
• Turn off the input power to the power source
at the disconnect switch or fuse box before
working on this equipment. Turn off the input
power to any other equipment connected to
the welding system at the disconnect switch
or fuse box before working on this equipment.
• Do not touch electrically hot parts.
--------------------------------------------------------
** Tabled values are for operation at ambient temperatures of 40°C and below. Applications above 40°C
may require cables larger than recommended, or cables rated higher than 75°C.
Amperes
200
200
225
225
250
250
250
250
300
325
350
400
400
500
Percent
Duty
Cycle
60
100
20
40 & 30
30
40
60
100
60
100
60
60
100
60
200 to 250 Ft.
61 to 76 m
1/0
1/0
1/0
1/0
1/0
1/0
1/0
1/0
2/0
3/0
3/0
4/0
4/0
4/0
150 to 200 Ft.
48 to 61 m
1
1
1
1
1
1
1
1
1/0
2/0
2/0
3/0
3/0
3/0
100 to 150 Ft.
31 to 48 m
2
2
2
2
2
1
1
1
1
2/0
2/0
2/0
3/0
3/0
50 to 100Ft.
15 to 31 m
2
2
3
3
3
2
1
1
1
2/0
1/0
2/0
3/0
2/0
0 to 50 Ft.
0 to 15 m
2
2
4 or 5
3
3
2
1
1
1
2/0
1/0
2/0
3/0
2/0
RECOMMENDED CABLE SIZES (RUBBER COVERED COPPER - RATED 75°C)**
CABLE SIZES FOR COMBINED LENGTHS OF ELECTRODE AND WORK CABLES
WELD CABLE SIZES
Table A.1 has the copper cable sizes recommended
for different currents and duty cycles. Lengths
stipulated are the distance from the welder to work
and back to the welder again. Cable sizes are
increased for greater lengths primarily for the purpose
of minimizing voltage in the welding circuit.
TABLE A.1

A-5
INSTALLATION
LF-72
A-5
COAXIAL WELD CABLES
Coaxial welding cables are specially designed
welding cables for pulse welding or STT welding.
Coaxial weld cables feature low inductance, allowing
fast changes in the weld current. Regular cables have
a higher inductance which may distort the pulse or
STT wave shape. Inductance becomes more severe
as the weld cables become longer.
Coaxial weld cables are recommended for all pulse
and STT welding, especially when the total weld
cable length (electrode cable + work cable) exceeds
50 feet (7.6m)
A coaxial weld cable is constructed by 8 small leads
wrapped around one large lead. The large inner lead
connects to the electrode stud on the power source
and the electrode connection on the wire feeder. The
small leads combine together to form the work lead,
one end attached to the power source and the other
end to the work piece.
(See Coaxial weld Cable below.)
WELD CABLE CONNECTION
Connect a work lead of sufficient size between the
proper output stud on the power source and the
work. Be sure the connection to the work makes
tight metal to metal electrical contact. Poor work
lead connections can result in poor welding
performance.

A-6
INSTALLATION
LF-72
A-6
ANALOG CONTROL CABLE
CONTROL CABLE CONNECTIONS
• All control cables can be connected end to end to
extend their length.
The control cable connecting the wire feeder to the
power source is specially made for the welding
environment.
The wire feeder power requires overcurrent
rotection. Connect the wire feeder only to power
sources with overcurrent protection of no more than
15 amps.
PIN FUNCTION LEAD#
A Unused -------
B Reserved -------
C Welding Output Control 2
(trigger from feeder)
D Welding Output Control 4
(trigger from feeder)
E Remote Voltage Control 77
(“+” supply from feeder or remote)
F Remote Voltage Control 76
(control signal from feeder or remote)
G Remote Voltage Control 75
(“-” supply from feeder or remote)
H Reserved
I 42 VAC 41
J Reserve for Future Use.
K 42 VAC 42
L Reserve for Future Use.
M Unused -------
N Electrode voltage from feeder 67
Do not use more than 100 ft (30.5 m) of control cable
between the wire feeder and power source.

A-7
INSTALLATION
LF-72
A-7
ANALOG MILLER CONTROL CABLE
ADAPTER K2335-1
This Lincoln Electric wire feeder may be mounted to a
limited number of Miller Electric power sources. The Miller
power source must have the amphenol pin definition shown
in the table below for proper operation of the wire feeder.
Operation of Lincoln wire feeders on Miller power sources
may result in lack of high speeds or reduce pull force on
high wire feed speeds. Maximum wire feed speed for the
LF-72 operating on a Miller power source is approximately
720ipm. Be sure the Miller power source provides 24 VAC
to the wire feeder and has overcurrent protection of no
more than 15 amps. The power source must not exceed
113VDC peak.
MILLER POWER SOURCE
Pin Function
A 24 VAC to feeder
B Welding Output Control
C +10VDC to feeder for remote control
D Remote control common
E 0-10VDC from feeder for remote control.
F Current feedback to feeder.
Scaled 0-10V. 1 V = 100 amps.
Referenced to pin D.
G 24 VAC common.
H Arc Voltage feedback to feeder.
Scaled 0-10V. 1 V = 10 Arc volts.
Referenced to pin D.
I
J
K
L
M
N
LINCOLN WIRE FEEDER
Pin Function
I 42 VAC feeder
D Welding Output Control
C Welding Output Control
E Remote Voltage Control ("+" supply, from
power source)
G Remote Voltage Control ("-" supply, from
power source)
F Remote Voltage Control (control signal from
feeder or remote.)
J Reserved for future use.
K 42 VAC to feeder
L Reserved for future use.
N Electrode voltage to power source (67)
Miller is a registered trademark not owned or licensed by The Lincoln Electric Company.

WELDING GUN/WIRE FEEDER TRIGGER
CONNECTOR
Wire Feeder
Pin Function
A Gun Trigger
B -
C Common
D -
E -
HIGH FREQUENCY PROTECTION
Locate the LF-72 away from radio controlled
machinery. The normal operation of the LF-72 may
adversely affect the operation of RF controlled
equipment, which may result in bodily injury or
damage to the equipment
A-8
INSTALLATION
LF-72
A-8
REMOTE SENSE LEAD SPECIFICATIONS
Refer to the power source instruction manual for
instructions for connecting the wire feeder for STT
welding.
WIRE DRIVE SYSTEMS
Drive Roll Kits are designed to feed specific types
and wire sizes. The LF-72 Bench Model comes with
the combo KP1696-1. All other Drive Roll Kits listed
are not included, but are available for ordering from
the following tables:
Drive Roll Kits, Steel Wires
Includes: 2 Smooth V groove drive rolls and an inner
wire guide.
KP1696-030S .023-.030 (0.6-0.8mm)
KP1696-035S .035 (0.9mm)
KP1696-045S .045 (1.2mm)
KP1696-052S .052 (1.4mm)
KP1696-1/16S 1/16 (1.6mm)
KP1696-1 .035, .O45 (0.9, 1.2mm)
KP1696-2 .040 (1.0mm)
Drive Roll Kits, Cored Wires
Includes: 2 Knurled drive rolls and an inner wire guide.
KP1697-035C .030-.035" (0.8-0.9mm)
KP1697-045C .040-.045" (1.0-1.2mm)
KP1697-052C .052" (1.4mm)
KP1697-1/16C 1/16" (1.6mm)
KP1697-068 .068-.072" (1.7-1.8mm)
KP1697-5/64C 5/64" (2.0mm)
Drive Roll Kits, Aluminum Wire
Includes: 2 polished U groove drive rolls, outer wire
guide and an inner wire guide.
KP1695-035A .035" (0.9 mm)
KP1695-040A .040" (1.0mm)
KP1695-3/64A 3/64" (1.2mm)
KP1695-1/16A 1/16" (1.6mm)
DRIVE ROLLS
INNER WIRE
GUIDE

A-9
INSTALLATION
LF-72
A-9
WELDING GUNS, TORCHES AND
ACCESSORIES
GUN RECEIVER BUSHING
The LF-72 wire feeder comes with a K1500-2 gun
receiver bushing.
MAGNUM GUN AND CABLE ASSEMBLIES
The LF-72 wire feeder model will accept a number of
optional gun and cable assemblies.
1. Turn off power at the welding power source.
2. Unscrew Thumb screw on Wire Drive Unit, until tip
of screw no longer protrudes into gun bushing
hole as seen from the front of machine.
3. Fully insert the gun cable connector end into the
gun receiver bushing and gently tighten the thumb
screw as show in Figure A.5.
4. Connect the gun trigger connector to the trigger
receptacle. Make sure that the key ways are
aligned and insert.

WIRE DRIVE CONFIGURATION
(See Figure A.5)
Changing the Gun Receiver Bushing
ELECTRIC SHOCK can kill.
• Turn the input power OFF at the
disconnect switch or fuse box
before attempting to connect or
disconnect input power lines, out-
put cables or control cables.
• Only qualified personnel should perform this
installation.
-----------------------------------------------------------
Tools required:
• 1/4" hex key wrench
Note: Some gun bushings do not require the use of
the thumb screw.
1. Turn power off at the welding power source.
2. Remove the welding wire from the wire drive.
3. Remove the thumb screw from the wire drive.
4. Remove the welding gun from the wire drive.
5. Loosen the socket head cap screw that holds the
connector bar against the gun bushing. Important:
Do not attempt to completely remove the socket
head cap screw.
6. Remove the outer wire guide, and push the gun
bushing out of the wire drive. Because of the pre-
cision fit, light tapping may be required to remove
the gun bushing.
PROCEDURE FOR CHANGING DRIVE
AND IDLE ROLL SETS
(See Figure A.4 )
ELECTRIC SHOCK can kill.
• Turn the input power OFF at the
welding power source before
installation or changing drive rolls
and/or guides.
• Do not touch electrically live parts.
• When inching with the gun trigger, electrode
and drive mechanism are "hot" to work and
ground and could remain energized several
seconds after the gun trigger is released.
• Only qualified personnel should perform
maintenance work.
-----------------------------------------------------------
1. Turn power off at the welding power source.
2. Release the idle roll pressure arm.
3. Remove the outer wire guide by turning the
knurled thumbscrews counter-clockwise to
unscrew them from the feed plate.
4. Rotate the triangular lock and remove the drive
rolls. FIGURE A.4
5. Remove the inner wire guide.
6. Insert the new inner wire guide, groove side out,
over the two locating pins in the feed plate.
7. Install a drive roll on each hub assembly secure
with the triangular lock.
8. Install the outer wire guide by aligning it with the
pins and tightening the knurled thumbscrews.
9. Close the idle arm and engage the idle roll pres-
sure arm. Adjust the pressure appropriately.
A-10
INSTALLATION
LF-72
A-10
WARNING WARNING
FIGURE A.5

A-11
INSTALLATION
LF-72
A-11
PRESSURE ARM ADJUSTMENT
ELECTRIC SHOCK can kill.
• Turn the input power OFF at the
welding power source before
installation or changing drive rolls
and/or guides.
• Do not touch electrically live parts.
• When inching with the gun trigger, electrode
and drive mechanism are "hot" to work and
ground and could remain energized several
seconds after the gun trigger is released.
• Only qualified personnel should perform
maintenance work.
-----------------------------------------------------------
The pressure arm controls the amount of force the
drive rolls exert on the wire. Proper adjustment of the
pressure arm gives the best welding performance.
Set the pressure arm as follows (See Figure A.6):
Aluminum wires between 1 and 3
Cored wires between 3 and 4
Steel, Stainless wires between 4 and 6
FIGURE A.6
WARNING
Gun Receiver For use With
Bushing
K1500-1 K466-1 Lincoln gun connectors;
Innershield and Subarc guns)
K1500-2 K466-2, K466-10 Lincoln gun
connectors; Magnum 200/300/400
guns and compatible with Tweco®
#4)
K1500-3 K1637-7 Lincoln gun connectors;
Magnum 550 guns and compatible
with Tweco® #5)
K1500-4 K466-3 Lincoln gun connectors;
compatible with Miller® guns.)
K1500-5 (Compatible with Oxo® guns.)
K489-7 ( Lincoln Fast-Mate guns.)
7. Disconnect the shielding gas hose from the gun
bushing, if required.
8. Connect the shielding gas hose to the new gun
bushing, if required.
9. Rotate the gun bushing until the thumb screw hole
aligns with the thumb screw hole in the feed plate.
Slide the gun receiver bushing into the wire drive
and verify the thumb screw holes are aligned.
10. Tighten the socket head cap screw.
11. Insert the welding gun into the gun bushing and
tighten the thumb screw.

3. Re-install the retaining collar. Make sure that the
release bar snaps out and that the retaining collar
fully engages the groove on the spindle.
Loading 30 lb. (13.6 kg) Readi-Reels
(See Figure A.9)
A K363-P Readi-Reel adapter is required for loading
these spools on 2" (51mm) spindles.
1. Squeeze the release bar on the retaining collar and
remove it from the spindle.
2. Place the Readi-Reel adapter on the spindle,
aligning the spindle brake pin with one of the holes
in the adapter.
3. Re-install the retaining collar. Make sure that the
release bar snaps out and that the retaining collar
fully engages the groove on the spindle.
4. Rotate the spindle and adapter until the retaining
spring is at the 12 o’clock position.
5. Position the Readi-Reel so that electrode de-reels
in the proper direction.
6. Set one of the Readi-Reel inside cage wires on the
slot in the retaining spring.
7. Lower the Read-Reel to depress the retaining
spring and align the other inside cage wires with
the grooves in the adapter.
8. Slide the cage all way onto the adapter until the
retaining spring "pops up" fully.
Removing a Readi-Reel
1. To remove a Readi-Reel from the an adapter,
depress the retaining spring with a thumb while
pulling the Readi-Reel cage from the adapter with
both hands. Do not remove the adapter from the
spindle.
WIRE REEL LOADING
• Keep hands, hair, clothing and tools away from
rotating equipment.
• Do not wear gloves when threading wire or
changing wire spool.
• Only qualified personnel should install, use or
service this equipment.
-----------------------------------------------------------
Loading 10 to 15 lb. (4.5 – 6.8kg) Spools
A K468 spindle adapter is required for loading 2"
wide spools on 2" (51mm) spindles. Use a K468-1
spindle adapter for loading 2-1/2" (64mm) wide
spools. (See figure A.7 and figure A.8)
1. Squeeze the release bar on the retaining collar and
remove it from the spindle.
2. Place the spindle adapter on the spindle, aligning
the spindle brake pin with the hole in the adapter.
3. Place the spool on the spindle and align the
adapter brake tab with one of the holes in the back
side of the spool. An indicator mark on the end of
the spindle shows the orientation of the brake tab.
Be certain the wire feeds off of the spool in the
proper direction.
4. Re-install the retaining collar. Make sure that the
release bar snaps out and that the retaining collar
fully engages the groove on the spindle.
FIGURE A.7
Spindle Placement
The wire reel stand provides two mounting locations
for the spindle. Each mounting location consists of a
tube in the center of the mast and locating slots.
Loading 16 to 44 lb. (7.3 – 20kg) Spools
(See figure A.8)
1. Squeeze the release bar on the retaining collar and
remove it from the spindle.
2. Place the spool on the spindle, aligning the spindle
brake pin with one of the holes in the back side of
the spool. An indicator mark on the end of the
spindle shows the orientation of the brake holding
pin. Be certain the wire feeds off of the spool in
the proper direction.
A-12
INSTALLATION
LF-72
A-12
FIGURE A.8
Adapter
Retaining
Collar
WARNING

A-13
INSTALLATION
LF-72
A-13
WELD WIRE ROUTING
The electrode supply may be either from reels,
Readi-Reels, spools, or bulk packaged drums or
reels. Observe the following precautions:
a) The electrode must be routed to the wire drive
unit so that the bends in the wire are at a
minimum, and also that the force required to pull
the wire from the reel into the wire drive unit is
kept at a minimum.
b) The electrode is “hot” when the gun trigger is
pressed and must be insulated from the boom
and structure.
c) If more than one wire feed unit shares the same
boom and are not sharing the some power
source output stud, their wire and reels must be
insulated from each other as well as insulated
from their mounting structure.
FIGURE A.9