Lincoln Electric IM10163 User Manual

Operator’s Manual

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FLEX FEED ™74 HT

For use with machines having Code Numbers:

12039 - 12052

Save for future reference

Date Purchased

Code: (ex: 10859)

Serial: (ex: U1060512345)

IM10163 | Issue D ate Nov-13

© Lincoln Global, Inc. All Rights Reserved.

Register your machine:

www.lincolnelectric.com/registration

Authorized Service and Distributor Locator:

www.lincolnelectric.com/locator

THANK YOU FOR SELECTING
A QUALITY PRODUCT BY
LINCOLN ELEC TRIC.

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.

WARNING

This statement appears where the information must be followed
exactly to avoid serious personal injury or loss of life.

CAUTION

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 Material Safety

Data Sheet (MSDS) 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 de velop 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.

SECTION A:

WARNINGS

CALIFORNIA PROPOSITION 65 WARNINGS

Diesel Engines

Diesel engine exhaust and some of its constituents are known
to the State of California to cause cancer, birth defects, and other
reproductive harm.

Gasoline Engines

The engine exhaust from this product contains chemicals known
to the State of California to cause cancer, birth defects, or other
reproductive harm.

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.

SAFETY

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

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.

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 pos­sible to the area being welded.

2.d.5. Do not work next to welding power source.

3

SAFETY

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

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 It ems 6.c. and 8.

between the

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 with

electrodes which require special ventilation such
as stainless or hard facing (see instructions on
container or MSDS) 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. In confined spaces or in
some circumstances, outdoors, a respirator may
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

injury or death. Always use enough ventilation, especially in
confined areas, to insure breathing air is safe.

cause

5.e. Read and understand the manufacturer’s instructions for this

equipment and the consumables to be used, including the
material safety data sheet (MSDS) and follow your employer’s
safety practices. MSDS forms are available from your welding
distributor or from the manufacturer.

5.f. Also see item 1.b.

4

SAFETY

a

m

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.

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 1235 Jefferson Davis
Highway, Arlington, VA 22202.

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.

6.j. Do not use a welding power source for pipe thawing.

Refer to

http://www.lincolnelectric.com/safety

for additional

safety information.

Welding Safety
Interactive Web Guide
for mobile devices

Get t he f r ee mobi l e app

http://gettag.

5

FLEX FEED™ 74 HT

Product Description ......................................................................................................................7

Installation.......................................................................................................................Section A

TABLE OF CONTENTS

Page

Technical Specifications.......................................................................................................A-1

Model Numbers for Basic and Advanced User Interface .....................................................A-2

Safety Precaution.................................................................................................................A-3

Location and Drive Roll and Wire Guides ...............................................................

Feed Plate Pressure Adjustment ..................................................................................A-4

Gun Adapters ................................................................................................A-5 thru A-11

Pinion Gear Ratio........................................................................................................A-12

Rotating the Feed Plate ..............................................................................................A-13

Left Hand Wire Drive...................................................................................A-14 thru A-22

Water Cooling Kit ..................................................

Shielding Gas...........................................................................................................

Loading Spools of Wire .....................................................................................A-25, A-26

Wire Reel Stands ........................

Electrical Installation ...................................................................................................A-28

Non Lincoln Equipment Adapter .................................................................................A-29

Relay Connections..............................

................................................................................A-27

........................................................................A-30

......................................................A-23

......A-3

.

..A-24

Operation...........

Graphic Symbols................................................................................

Duty Cycle............................................................................................................................B-2

Recommended Processes ...................................................................................................B-2

Process Limitations ..............................................................................................................B-2

Equipment Limitations..........................................................................................................B-2

Recommended Power Sources............................................................................................B-2

Front and Side View.............................................................................................................B-3

Rear View.............................................................................................................................B-4

Wire Feed Speed Knob........................................................................................................B-5

Remote Voltage Control Knob..............................................................................................B-5

2-Step / Trigger Interloock Switch .......................................................................................

Thermal LED ........................................................................................................................B-5

Cold Feed.............................................................................................................................B-5

Gas Purge ............................................................................................................................B-5

Digital Meters .......................................................................................................................B-5

Timer Kit.....................

Power Up Sequence ............................................................................................................B-6

User Interface.......................................................................................................................B-6

Gouging Kit...........................................................................................................................B-7

..

..................................

..........................................................................................................B-5

..

........................................................................Section B

..................................B-1

.

B-5

Accessories.....................................................................................................Section C

Optional Kits and Accessories...............................................................................C-1

Gun Adapter Kits.............................................................................................C-2

Cables......................................

General Accessories ...........................................................................................................

....................................................................................

C-3
C-4

Accessories Included with the Flex Feed™ 74 HT................................................C-5

Maintenance.....................................................................................................Section D

Safety Precautions ................................................................................................D-1

Routine Maintenance.............................................................................................D-1

Periodic Maintenance............................................................................................D-1

Calibration Specification........................................................................................D-1

Troubleshooting..............................................................................................Section E

Safety Precautions.................................................................................................E-1

How to Use Troubleshooting Guide.......................................................................E-1

Troubleshooting Guide...................................................................................E-2, E-3

Wiring Diagrams and Dimension Prints........................................................Section F

________________________________________________________________________

Parts List.................................................................................................................P-747

6

FLEX FEED™ 74 HT

PRODUCT DESCRIPTION

GENERAL PHYSICAL DESCRIPTION

The Flex Feed 74 HT is a heavy duty industrial wire feeder. At
the heart of the feeder is the proven wire drive and motor, capa­ble of feeding large diameter electrodes and pulling through long
conduits.

The feed plate may be located on either the left or right hand
side of the wire drive housing for easy integration into any work
center. The feed plate rotates easily to lessen strain on the gun.

Two wire reel stands are available for optimizing the feeder size
to the consumable package.

A new series of gun adapters has been created for improved reli­ability and lower voltage drop.

GENERAL FUNCTIONAL DESCRIPTION

The base model Flex Feed™ 74 HT has knobs for wire feed
speed and remote voltage control. A large rocker switch on the
side of the feeder allows for activation of Cold Feed and Gas
Purge.

2-step/Trigger Interlock offers operator comfort when making
long welds.

Two wire feed speed ranges are available, dependent upon the
pinion gear installed in the wire drive.

The advanced user interface includes digital meters for the dis­play of amperage and voltage while welding. The displays do
not show preset values. The user interface also has timers for
preflow, burnback and postflow.

The gouging option provides a means for connecting the gouging
torch to the feeder and a switch for activating the power source
output. High powered contactors inside the wire feeder isolate
the wire drive and the gouging circuit.

7

TECHNICAL SPECIFICATIONS – FLEX FEED™ 74 HT (K3883-XX)

INPUT VOLTAGE and CURRENT

VOLTAGE

INPUT AMPERES

NOTES

INSTALLATIONFLEX FEED™ 74 HT

24 – 42 VAC

No Gouging Kit

With Gouging Kit

GEARING - WIRE FEED SPEED RANGE-WIRE SIZE

PINION GEAR

20 tooth

30 tooth

*

HEIGHT WIDTH DEPTH WEIGHT

10A

RATED OUTPUT @ 104°F (40°C)

DUTY CYCLE

Wire Drive
Wire Drive

Gouging Stud

WFS RANGE

50 – 500 inch/min

(1.3 – 12.7 m/min)

50 – 700 inch/min

(1.3 – 19.0 m/min)

.025” – 3/32”

(0.6 – 2.4 mm)

.025” – 1/16”

(0.9 – 1.6 mm)

60%
60%
30%

WIRE SIZES

GMAW

PHYSICAL DIMENSIONS

Wire Drive

INPUT AMPERES

600 Amps
500 Amps
600 Amps

FCAW

.035” - .120”

(0.9 – 3.0 mm)

.035 – 5/64”

(0.9 – 2.0 mm)

Wire 11.1 Inches 13.6 Inches 13.3 Inches 36 lbs.
Drive ( 294mm) (345mm) (337mm) (16.3kg)
(only)

TEMPERATURE RANGE

OPERATION: -40°F to 104°F (-40°C to 40°C)
STORAGE: -40°F to 122°F (-40°C to 50°C)

Thermal tests have been performed at ambient temperature. The Duty Cycle (duty factor) @ 40ºC (104°F) has
been determined by simulation.

* = gearing installed in the wire drive as equipped from the factory.

IP2X for the wire drive and user interface.

A-1

MODEL NUMBERS FOR BASIC AND ADVANCED USER INTERFACE

INSTALLATIONFLEX FEED™ 74 HT

MODEL K#

K3883-1
K3883-2
K3883-3
K3883-4
K3883-5
K3883-6
K3883-7
K3883-8

K3883-9
K3883-10
K3883-11
K3883-12
K3883-13
K3883-14
K3883-15
K3883-16
K3883-17

User Interface

Basic

Advanced

Basic

Advanced

Basic

Advanced

Basic
Advanced
Advanced
Advanced

Basic
Advanced

Basic
Advanced

Basic

Basic

Basic

Wire Reel Stand

-

-

-

­Standard Duty
Standard Duty
Standard Duty
Standard Duty
Standard Duty
Standard Duty

Heavy Duty
Heavy Duty
Heavy Duty
Heavy Duty
Heavy Duty
Heavy Duty
Heavy Duty

Gun

-

-

-

-

-

-

-

­300A-.035-.045
400A-.052-1/16

-

-

-

­300A-.035-.045
400A-.052-1/16

K126 PRO

Gouging Kit

-

­Yes
Yes

-

­Yes
Yes

-

-

-

­Yes
Yes
Yes
Yes
Yes

A-2

FLEX FEED™ 74 HT

INSTALLATION

SAFETY PRECAUTIONS

WARNING

ELECTRIC SHOCK CAN KILL.

• ONLY QUALIFIED PERSONNEL
SHOULD PERFORM THIS
INSTALLATION.

• Turn the input power OFF at the

disconnect switch or fuse box
before attempting to connect or
disconnect input power lines,
output cables or control cables.

• Do not touch the wire drive, drive rolls, wire
coil or electrode when welding output is ON.

• Wire feeder may be connected to a piece of
automatic equipment that may be remotely
controlled.

• Do not operate with covers, panels or guards
removed.

• Do not let the electrode or wire spool touch the
wire feeder housing.

• Insulate yourself from the work and ground.

• Always wear dry insulating gloves.

• The lift bail is insulated from the wire feeder
enclosure. If an alternate hanging device is
use. it must be insulated from the wire feeder
enclosure.

MOVING PARTS can injure.

• Keep away from moving parts.

-------------------------------------------------------------------

LOCATION

The Flex Feed 74 HT is rated IP2X and is suitable
for indoor use.

For best wire feeding performance, place the Flex
Feed 74 HT on a stable and dry surface.

When suspending the wire feeder, insulate the
hanging device from the wire feeder enclosure.

DRIVE ROLL AND WIRE GUIDES

(See Figure A.1)

1. Turn power OFF at the welding power source.

2. Open the wire drive door by pulling on the top.

3. Remove the outer wire guide.

4. Remove drive rolls by pulling straight out. It may be
necessary to wiggle the drive roll to free it from the
snap ring.

5. Remove the inner wire guide.

6. Install the new inner wire guide, with the arrow
pointing in the direction of wire travel.

7. Install the drive rolls and outer wire guide.

8. Close the wire drive door and adjust the pressure
setting accordingly.

FIGURE A.1

A-3

INNER WIRE DRIVE

DIVE ROLLS

OUTER WIRE DRIVE

FEED PLATE PRESSURE ADJUSTMENT

(See Figure A.2)

• Most wires operate well with a pressure setting of “2”.
The best drive roll pressure varies with wire type, wire

urface, lubrication and hardness. Too much pressure

s
may crush the wire or cause "birdnesting", but too lit­tle pressure could cause slippage.

Set the drive roll pressure by:

1. Press the end of the gun against a solid object that is

electrically isolated from the welder output and press
the gun trigger for several seconds.

2. If the wire "birdnests" or jams, the drive roll pressure

is too high. Reduce the pressure by one turn of the
knob, run new wire through the gun, and repeat step

1.

3. If the only result is slippage, disconnect the gun and

pull the gun cable forward about 6" (150mm). There
should be a slight waviness in the exposed wire. If
there is no waviness, increase the pressure setting
one turn, reconnect the gun and repeat the above
steps.

INSTALLATIONFLEX FEED™ 74 HT

FIGURE A.2

PRESSURE
ADJUST KNOB

A-4

GUN ADAPTERS:

K3344-1 LINCOLN
K3345-1 STANDARD #4
K3346-1 STANDARD #5
K3347-1 MILLER

GUN ADAPTER REPLACEMENT PROCEDURE

1. Turn power OFF at the welding power source.

2. Using a Phillips screw driver, loosen the screw
securing the gun adapter cover. Remove the gun
adapter cover.

FIGURE A.3

SCREW

GUN
ADAPTER
COVER

INSTALLATIONFLEX FEED™ 74 HT

3. With a 3/4” wrench, remove the bolt holding the
electrode lead to the gun adapter.

FIGURE A.4

BOLT

ELECTRODE
LEAD

A-5

4. Use a 1/8” hex key to loosen the set screw securing
the gun adapter.

FIGURE A.5

SET SCREW

INSTALLATIONFLEX FEED™ 74 HT

GUN ADAPTER

A-6

5. Remove the sense lead with a Phillips screw driver.

FIGURE A.6

SENSE
LEAD

INSTALLATIONFLEX FEED™ 74 HT

6. If a gas hose is attached to the gun adapter, use pliers
to remove the hose clamp and remove the gas hose.

7. If the gun adapter requires guide tubes, install the
correct size guide tube and secure with the set screw.

FIGURE A.7

SET SCREW

GUIDE TUBE

Wire size Number of grooves in guide tube
.023-.045” ( 0.6 – 1.2mm) 1
.045 – 1/16” (1.2 – 1.6 mm) 2
1/16 – 5/64” (1.6 – 2.0 mm) 3
.068 – 7/64” (2.0 – 2.8 mm) 4
.120 ” (3.0 mm) No Guide Tube Required

A-7

8. Assemble the sense lead to the new gun adapter.
Orient the lead to towards the rear of the gun adapter.

9. If required, assemble the gas hose to the gun adapter
or the fitting on the feed plate and secure with a hose
clamp.

10. Assemble the gun adapter to the wire drive. Tighten

the set screw once the gun adapter is at a 90° angle.

11. Bolt the electrode lead to the gun adapter, making

sure to route the lead straight down.

FIGURE A.8

BOLT

INSTALLATIONFLEX FEED™ 74 HT

ELECTRODE
LEAD

12. Assemble the gun adapter cover and secure with the

screw.

FIGURE A.9

SCREW

GUN
ADAPTER
COVER

KEEP TERMINAL AND
LEAD VERTICAL.

A-8

GUN ADAPTERS:

K3348-1 OXO
K3349-1 FASTMATE

• Using the Oxo or FastMate gun adapters requires a
K3344-1 Standard #4 gun adapter to be installed in the
wire drive.

1. Turn power OFF at the welding power source.

2. Using a Phillips screw driver, loosen the screw securing
the gun adapter cover. Remove the gun adapter cover.

FIGURE A.10

SCREW

GUN
ADAPTER
COVER

INSTALLATIONFLEX FEED™ 74 HT

3. With a 3/4” wrench, remove the bolt holding the
electrode lead to the gun adapter.

FIGURE A.11

BOLT

A-9

ELECTRODE
LEAD

4. Using pliers, remove the hose clamp and hose from the
gun adapter.

5. Bolt the electrode lead to the gun adapter, making sure
to route the lead straight down.

FIGURE A.12

BOLT

INSTALLATIONFLEX FEED™ 74 HT

ELECTRODE
LEAD

KEEP TERMINAL AND
LEAD VERTICAL.

A-10

6. Assemble the gun adapter cover and secure with the

screw.

FIGURE A.13

SCREW

GUN
ADAPTER
COVER

7. Assemble the gas hose to the Oxo or FastMate gun
adapter.

8. Select the appropriate guide tube and secure with the
set screw.

INSTALLATIONFLEX FEED™ 74 HT

FIGURE A.14

SET SCREW

Wire size Number of grooves in guide tube

.023-.045” ( 0.6 – 1.2mm) 1

.045 – 1/16” (1.2 – 1.6 mm) 2

1/16 – 5/64” (1.6 – 2.0 mm) 3

.068 – 7/64” (2.0 – 2.8 mm) 4

GUIDE TUBE

9. Slide the Oxo or FastMate gun adapter into the wire
drive and secure with the thumb screw.

10. For FastMate gun adapters, connect the trigger pigtail

to the connector on the front of the feeder.

A-11

PINION GEAR RATIO

As shipped from the factory, a 20 tooth pinion gear is
installed. If desired, the 30 tooth pinion gear may be
installed for more speed but less torque.

FIGURE A.15

INSTALLATIONFLEX FEED™ 74 HT

1. Turn power OFF at the welding power source.

2. Open the wire drive door and loosen the set screw
holding the hinge pin using a 5/64” hex key. Slide the
hinge pin towards the rear and remove the door.

FIGURE A.16

HINGE PIN

SET SCREW

A-12

INSTALLATIONFLEX FEED™ 74 HT

3. Remove the two socket head cap screws securing the
feed plate and remove the feed plate from clamp using
a 1/4” hex key.

FIGURE A.17

(2) SOCKET HEAD
CAP SCREWS

4. Remove the screw holding the pinion gear using a
Phillips screw driver. Remove the pinion gear.

5. Install the new pinion gear.

6. Position the feed plate and tighten the socket head cap
screws.

7. Re-assemble the hinge pin and door. Secure the hinge
pin with the set screw.

8. Remove the (4) screws securing the roof with a 5/16”
nut driver.

9. Locate the leads 586 and 515E. The ends of the leads
have pink terminals cable tied into a bundle close to
the pc board.

• 20 tooth pinion gear: connect 586 to 515E

• 30 tooth pinion gear: disconnect 586 to 515E

10. Apply/remove the wire feed speed decal from the

name plate as follows:

Speed Range Decal

50 – 500 in/min Default value. Remove any decals applied to the

nameplate.

50 – 700 in/min M24808-1

1.5 – 12.5 m/min M24808-2

1.5 – 18 m/min M24808-3

ROTATING THE FEED PLATE

1. Turn power OFF at the welding power source.

2. Locate the socket head cap screw at the bottom of the
wire drive. Loosen, but do not remove the screw using
a 1/4” hex key.

FIGURE A.18

SOCKET HEAD CAP SCREW

3. Rotate the wire drive to the desired position and tighten
the screw.

Decals are located in the literature of the feeder.

A-13

INSTALLATIONFLEX FEED™ 74 HT

LEFT HAND WIRE DRIVE

The Flex Feed 74 HT may be reassembled with the wire
drive on the left hand side. To convert to a left hand wire
drive:

Requires: G7644-1 Gun adapter cover, left

Tools required:

• Molex Mini-Fit JR Extraction Tool, part #11-03-0044

• Phillips Screw Driver

• 3/8” wrench

• 11/16” wrench

• 3/4” wrench

• 1/4” nut driver

• 5/16” nut driver

• 1/8” hex key

• 1/4 hex key

• pliers

1. Turn OFF power at the welding power source.

2. Using a Phillips screw driver, loosen the screw securing
the gun adapter cover. Remove the gun adapter cover.

FIGURE A.19

SCREW

4. Use a 1/8” hex key to loosen the set screw securing
the gun adapter.

FIGURE A.21

SET SCREW

GUN ADAPTER

5. Remove the sense lead with a Phillips screw driver.

FIGURE A.22

SENSE
LEAD

GUN
ADAPTER
COVER

3. With a 3/4” wrench, remove the bolt holding the
electrode lead to the gun adapter.

FIGURE A.20

BOLT

ELECTRODE
LEAD

6. If a gas hose is attached to the gun adapter, use
pliers to remove the hose clamp and remove the gas
hose.

7. Loosen the socket head cap screw at the bottom of
the feed plate and slide the feed plate off of the gear
box.

FIGURE A.23

SOCKET HEAD CAP SCREW

A-14

INSTALLATIONFLEX FEED™ 74 HT

8. Remove the (4) screws securing the roof with a 5/16”
nut driver. Remove the remaining (2) screws securing
each case side.

FIGURE A.24

9. Remove the lock-nut holding the gas solenoid. Leave
the gas hose and leads connected to the gas solenoid.
Remove the plug button from the rear opposite the gas
solenoid.

FIGURE A.25

10. Remove the upper motor support. Use a 5/16” nut
driver to remove the (2) screws at the rear and the (2)
screws at the front. Use a 3/8” wrench to remove the
(3) screws holding the support to the gearbox.

FIGURE A.26

11. Remove the (4) screws holding the motor gearbox
assembly to the case and lift out the motor gearbox.

FIGURE A.27

A-15

12a. For feeders with digital displays only:

a. Unbolt the wire drive lead from the bus bar with a

3/4” wrench.

b. Unbolt the bus bar from the case (1/4” Hex key) and

the input stud.

c. Using a 1/4” nut driver, remove the current

transducer and reassemble to the left side.
d. Reassemble the bus bar to the case and input stud.
e. Bolt the wire drive lead to the left side of the bus bar.

FIGURE A.28

CURRENT
TRANSDUCER

INSTALLATIONFLEX FEED™ 74 HT

WIRE DRIVE
LEAD

12b. For wire feeders with a gouging kit installed:

a. Swap the gouging lead and wire drive lead

positions by using a 11/16” wrench.

b. Swap the leads to the contactor coils. Lead 549A

attaches to the wire drive contactor. Lead 549B
attaches to the gouging stud contactor. Lead 552 is
common to both contactors.

13. Change the polarity of the motor leads by swapping
the large black and white leads in the motor harness
plug.

FIGURE A.29

LEFT HAND
WIRE DRIVE

SPACERS

INSULATOR BUSHING

PLAIN WASHER

LOCKWASHER

RIGHT HAND
WIRE DRIVE

BLACK
TACH
LEAD

5

1234

RED
TACH
LEAD

YELLOW
TACH
LEAD

WHITE
MOTOR
LEAD

876

BLACK
MOTOR
LEAD

BLUE
TACH
LEAD

A-16

BLACK
TACH
LEAD

1234

RED
TACH
LEAD

YELLOW
TACH
LEAD

BLACK
MOTOR
LEAD

WHITE
MOTOR
LEAD

8765

BLUE
TACH
LEAD

INSTALLATIONFLEX FEED™ 74 HT

14. Place the motor gearbox assembly in the case with
the drive facing the left side. Secure with (4) screws.

FIGURE A.30

Reassemble the switch on the left side

15. Reassemble the upper motor support with plastic
washers on the appropriate side.

16. To move the Cold Feed/Gas Purge rocker switch from
the right side to the left side, remove the leads from
the switch. Squeeze the snaps holding the switch to
the sheet metal and push the switch outwards.

FIGURE A.31

559

515
515C

559

A-17

17. If present, reassemble the Gouge/Wire Feed switch
on the opposite side.

FIGURE A.32

522

INSTALLATIONFLEX FEED™ 74 HT

552F

515E

515G515F

18. Remove the (4) screws holding the user interface to
gain access to the inside front compartment of the
feeder.

19. Move the thermal LED from right to the left hand side.
Gently pull on the black body of the LED holder to
separate it from the clear lens.

FIGURE A.33

A-18

20. Swap the location of the plug button and the 5 pin
trigger connection on the front of the feeder, then
reassemble the user interface.

FIGURE A.34

5 PIN TRIGGER
CONNECTOR

21. Reassemble the gas solenoid and plug button to the
rear of the feeder.

22. Reassemble the case sides and roof to the feeder,
taking care to route the gas line and electrode sense
lead through the case side opening by the rear of the
motor gearbox.

FIGURE A.35

INSTALLATIONFLEX FEED™ 74 HT

PLUG
BUTTON

23. Reassemble the feed plate to the gear box and secure
by tightening the socket head cap screw.

FIGURE A.36

SOCKET HEAD CAP SCREW

67 ELECTRODE
SENSE LEAD

GAS HOSE

A-19

24a. Open the feed plate door.

a. Remove the screw holding the door insert.
b. Remove the (2) socket head cap screws.
c. Fully unscrew the pressure knob and slide the

washers and rod out of the door.

FIGURE A.37

(a)

DOOR INSERT
AND SCREW

PRESSURE ARMS

(b)

SOCKET HEAD
CAP SCREW

INSTALLATIONFLEX FEED™ 74 HT

RIGHT HAND
ASSEMBLY

(c)

PRESSURE KNOB
AND ROD

SOCKET HEAD CAP SCREW
SCREWS INTO THIS INDICATOR

A-20

24b. To reassemble the door for left hand operation:

a. Place the pressure arms on the door in the

orientation as shown.

b. Slide the rod through the door and through the

springs.

c. Assemble the socket head cap screws and

indicator, tightening the indicator screw to a

height of .27” and the other screw to .34”.
d. Assemble the washers and pressure knob.
e. Assemble the door insert.

FIGURE A.38

INSTALLATIONFLEX FEED™ 74 HT

(e)

DOOR INSERT
AND SCREW

(a) PRESSURE ARMS

SPRINGS

(b)

SLIDE ROD
THROUGH SPRINGS

(c)

SOCKET HEAD
CAP SCREW

SOCKET HEAD CAP SCREW
SCREWS INTO THIS INDICATOR

(d) WASHERS WITH

PRESSURE KNOB

LEFT HAND
ASSEMBLY

(c)
.34”

(c)
.27”

A-21

25. Place the gun adapter into the feed plate. If required,
swap the position of the barbed fitting with the plug.
Assemble the gas hose to the gun adapter.

26. Assemble the wire drive lead to the gun adapter. The
bolt for the wire drive lead will align the gun adapter
with the feed plate as the bolt is tightened. The
terminal of the lead must be in a vertical position.

FIGURE A.39

INSTALLATIONFLEX FEED™ 74 HT

TERMINAL OF LEAD
MUST BE VERTICAL

27. Tighten the set screw to secure the gun adapter in
place.

28. Secure the G7644-1 gun adapter cover in place with
the Phillips screw, lockwasher and plain washer.

FIGURE A.40

PHILLIPS SCREW,
LOCKWASHER AND
PLAIN WASHER

A-22

WATER COOLING KIT

The K590-6 water connection kit installs underneath the
wire drive.

1. Turn power OFF at the welding power source.

2. Install the quick disconnect fittings to the plastic

bracket, by holding the rear nut stationary and spinning
the fitting.

3. Cut the tubing to the desired length, and then install

the tubing and hose clamps to the fittings.

FIGURE A.41

INSTALLATIONFLEX FEED™ 74 HT

A-23

INSTALLATIONFLEX FEED™ 74 HT

SHIELDING GAS CONNECTION

CYLINDER may explode if

damaged.

•Keep cylinder upright and
chained to support.

• Keep cylinder away from areas where it may be
damaged.

• Never lift welder with cylinder attached.

• Never allow welding electrode to touch cylinder.

• Keep cylinder away from welding or other live
electrical circuits.

• BUILD UP OF SHIELDING GAS MAY
HARM HEALTH OR KILL.

• Shut off shielding gas supply when not in
use.

• See American National Standard Z-49.1, "Safety
in Welding and Cutting” Published by the
American Welding Society.

---------------------------------------------------------------

Maximum inlet pressure for the Flex Feed 74 HT is 100
psi. (6.9 bar.)

6. Before opening the cylinder valve, turn the regulator
adjusting knob counterclockwise until the adjusting
spring pressure is released.

7. Standing to one side, open the cylinder valve slowly a
fraction of a turn. When the cylinder pressure gage
stops moving, open the valve fully.

8. The flow regulator is adjustable. Adjust it to the flow

ate recommended for the procedure and process

r
being used before making a weld.

The inlet fitting is 5/8-18 CGA type connection.

Install the shielding gas supply as follows:

1. Secure the cylinder to prevent it from falling.

2. Remove the cylinder cap. Inspect the cylinder valves
and regulator for damaged threads, dirt, dust, oil or
grease. Remove dust and dirt with a clean cloth. DO

NOT ATTACH THE REGULATOR IF OIL, GREASE
OR DAMAGE IS PRESENT! Inform your gas supplier

of this condition. Oil or grease in the presence of high
pressure oxygen is explosive.

3. Stand to one side away from the outlet and open the
cylinder valve for an instant. This blows away any dust
or dirt which may have accumulated in the valve outlet.

4. Attach the flow regulator to the cylinder valve and tight­en the union nut(s) securely with a wrench. Note: if
connecting to 100% CO

cylinder, insert regulator

2

adapter between regulator and cylinder valve. If
adapter is equipped with a plastic washer, be sure it is
seated for connection to the CO

cylinder.

2

5. Attach one end of the inlet hose to the outlet fitting of
the flow regulator. Attach the other end to the welding
system shielding gas inlet. Tighten the union nuts with
a wrench.

A-24

LOADING SPOOLS OF WIRE

WARNING

• 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.

--------------------------------------------------------------------------

50 - 60 lb (22 – 27 kg) coils require K3343-1 Heavy
Duty Wire Reel Stand

1. Turn power OFF at the welding power source.

2. Squeeze the release bar on the retaining collar and
remove it from the spindle.

FIGURE A.42

INSTALLATIONFLEX FEED™ 74 HT

SQUEEZE
RELEASE
BAR

A-25

3. 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.

FIGURE A.43

INDICATOR
MARK

ALIGN BRAKE
PIN WITH HOLE

INSTALLATIONFLEX FEED™ 74 HT

4. Re-install the retaining collar, with the metal bar
engaging one of the grooves of the spindle. The
release bar will spring out when engaged.

A-26

WIRE REEL STANDS

K3342-1 Standard Duty Wire Reel Stand is for use with
spools 10 to 44 lb (4.5 to 20 kg)

When using the K3343-1 Heavy Duty Wire Reel, place the
spindle in the location as shown.

FIGURE A.44

INSTALLATIONFLEX FEED™ 74 HT

A-27

ELECTRICAL INSTALLATION

14 pin connector

The control cable connecting the wire feeder to the
power source is specially made for the welding
environment.

The wire feeder power requires overcurrent protection.
Connect the wire feeder only to power sources where
the overcurrent protection is no more than 15 amps.

Do not use more than 300 ft (30.5 m) of control cable
between the wire feeder and power source.

Pin Function Lead #

A- ­B- -

Welding Output Control (trigger to power source)

C

Welding Output Control (trigger to power source)

D

Remote Voltage Control ("+" supply, from power source)

E
F

Remote Voltage Control (control signal from feeder or remote)

G

Remote Voltage Control ("-" supply, from power source)
H Work connection from power source 21
I 24 - 42 VAC to feeder 41
J-­K 24 - 42 VAC to feeder 42
L-­M- ­N- -

2
4
77
76
75

INSTALLATIONFLEX FEED™ 74 HT

A-28

NON-LINCOLN EQUIPMENT ADAPTER,
K2335-1,-2

The Flex Feed 74 HT may be used with non-Lincoln
Electric power sources that provide 24 VAC. The
power source must have the circular connector pin
definition shown in the table below for proper opera­tion of the wire feeder. Be sure the 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.

Operation of Lincoln wire feeders on 24 VAC may
result in lack of high wire feed speeds or reduced pull
force at high wire feed speeds. Approximate maxi­mum WFS for Lincoln wire feeders operating with 24
VAC is:

20 tooth pinion gear 425 in/min
30 tooth pinion gear 600 in/min

INSTALLATIONFLEX FEED™ 74 HT

Power Source

K

M

A

B

L

C

D

E

H

J

I

N

G

F

NON-LINCOLN POWER SOURCE

Pin

24 VAC to feeder

A

Welding Output Control

B

+10VDC to feeder for remote control

C

Remote control common

D

0-10VDC from feeder for remote control.

E

Current feedback to feeder. Scaled 0-10V. 1 V =

F

100 amps. Referenced to pin D.
24 VAC common.

G

Arc Voltage feedback to feeder. Scaled 0-10V. 1
V = 10 Arc volts. Referenced to pin D.
Not used

N

Function

Wire Feeder

M

J

K

I

H

N

G

F

C

A

B

L

D

E

LINCOLN WIRE FEEDER

Pin

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

Not used

K

42 VAC to feeder

L

Not used

N

Not used

Function

A-29

RELAY CONNECTIONS

The Flex Feed™74 HT includes a DPDT relay for
switching power for accessories. The relay closes
whenever the gas solenoid turns on.

The ratings of the relay are:

Normally Open 30 amps @ 277 VAC 20 amp @ 28 VDC
Normally Closed 2 amps @ 480 VAC 3 amps @ 28 VDC

To make connections to the relay:

1. Turn power OFF at the welding power supply.

2. Remove the (4) screws securing the roof with a

5/16” nut driver.

3. Remove the (4) screw securing the User Interface

with a 5/16” nut driver.

4. Remove the plastic plug button at the rear of the

feeder and replace with an appropriate electrical
bushing. Route the wires through the bushing to the
relay.

5. Reassemble.

FIGURE A.44

INSTALLATIONFLEX FEED™ 74 HT

NORMALLY CLOSED
CONTACTS

786

24 3

NORMALLY OPENED
CONTACTS

A-30

FLEX FEED™ 74 HT

t

2

GRAPHIC SYMBOLS THAT APPEAR ON
FLEX FEED

™ 74 HT OR IN THIS MANUAL

OPERATION

U

WARNING OR
CAUTION

INPUT POWER

ON

OFF

POSITIVE OUTPUT

NEGATIVE OUTPUT

PROTECTIVE
GROUND

1

INPUT VOLTAGE

CONTACTOR

COLD FEED

GAS PURGE

SHIELDING GAS
INLET

SHIELDING GAS
OUTLET

PREFLOW

BURNBACK

POSTFLOW

I

1

I

2

A

V

2-STEP TRIGGER

INPUT CURRENT

TRIGGER INTER­LOCK

OUTPUT CURRENT

THREMAL

WELDING AMPERAGE

WELDING VOLTAGE

WIRE FEEDER

REMOTE VOLTAGE
CONTROL

GMAW/FCAW
PROCESS

CARBON ARC
GOUGING PROCESS

B-1

FLEX FEED™ 74 HT

OPERATION

DUTY CYCLE

The FLEX FEED™ 74 HT wire feeders are intended
for semi-automatic use. The maximum rating of the
FLEX FEED™ 74 HT is based upon a 60% duty cycle;
welding 6 minutes of welding followed by 4 minutes of
idling within a 10 minute period.

RECOMMENDED PROCESSES

• GMAW

• FCAW

• Hand-held SAW

• CCAG (with gouging option installed)

PROCESS LIMITATIONS

• Processes must be within the duty cycle and rating
of the wire feeder.

EQUIPMENT LIMITATIONS

• Does not include weld cables

• Operates on 24 – 42 VAC input

• Must use newer gun adapter kits. Not compatible
with K1500-1, K1500-2, K1500-3, K1500-4 K1500-5
and K489-7 gun adapter kits.

RECOMMENDED POWER SOURCES

Power Source

Flextec 450
Flextec 650
V-350
CV-305
CV-400
DC-400
DC-600
DC-655
DC-1000
Ranger 250 GXT
Ranger 305 G, LPG,D
Vantage 300
Vantage 400
Vantage 500
Air Vantage 500

B-2

FLEX FEED™ 74 HT

FRONT VIEW (See Figure B.1)

(ADVANCED USER INTERFACE SHOWN)

AMPS
DISPLAY

WIRE FEED
SPEED KNOB

PREFLOW

BURNBACK

OPERATION

FIGURE B.1

VOLTS
DISPLAY

REMOTE VOLTAGE
CONTROL KNOB

POSTFLOW

2-STEP/TRIGGER
INTERLOCK SWITCH

SIDE VIEW (See Figure B.2)

COLD FEED/
GAS PURGE SWITCH

TRIGGER CONNECTOR
(5 PIN)

FIGURE B.2

PRESSURE
ADJUST KNOB

THERMAL LED

B-3

FLEX FEED™ 74 HT

REAR VIEW (See Figure B.3)

SHIELDING
GAS INLET

OPERATION

ELECTRODE CONNECTION
(COVER NOT SHOWN FOR
CLARITY)

CONTROL CABLE WITH
14 PIN CINNECTOR

B-4

FLEX FEED™ 74 HT

OPERATION

WIRE FEED SPEED KNOB

Turn the wire feed speed knob clockwise to increase the
wire feed speed.

Two ranges of wire feed are available: 50 -700
inches/minute and 50 – 500 inches/ minute (factory
setting).

REMOTE VOLTAGE CONTROL KNOB

The remote voltage control knob adjusts the output of the
power source. The Flex Feed 74 HT does not display
preset voltage.

2-STEP/ TRIGGER INTERLOCK SWITCH

The 2-Step/Trigger Interlock switch changes the function
of the gun trigger. 2-Step trigger operation turns welding
on and off in direct response to the trigger. Trigger
Interlock operation allows welding to continue when the
trigger is released for comfort on long welds.

Place the rocker switch in the DOWN position for 2-Step
operation or in the UP position for Trigger Interlock
operation.

2-Step Trigger

2-Step trigger operation is the most
common. When the gun trigger is pulled, the
welding power source energizes the
electrode output and the wire feeder feeds
wire for welding. The power source and wire
feeder continue welding until the trigger is
released.

THERMAL LED:

The thermal LED is located on the side of the
Flex Feed 74 HT near the wire drive.

The thermal LED lights when the motor
current is too high. Inspect the gun and
conduit, verifying that the wire slides through
easily.

COLD FEED

Pressing the Cold Feed rocker switch feeds
wire at the wire feed speed indicated by the
knob without turning on the power source
output.

GAS PURGE

Pressing the Gas Purge rocker switch turns
on the gas solenoid for as long as the switch
is held.

The power source output remains OFF during
Gas Purge.

DIGITAL METERS

(Advanced User Interface Only)

The digital meter kit displays the amperage and voltage
while welding. There must be at least 10 amps and 10
volts present for the meters to show welding values.
Once welding stops, the displays continue to show the
last values for 5 seconds. The displays do not show
preset values. If a gouging kit is installed, the displays
only show the voltage while gouging and not amperage.

Trigger Interlock

Trigger Interlock operation provides for
operator comfort when making long welds.
When the gun trigger is first pulled, the
welding power source energizes the output
and the wire feeder feeds wire for welding.
The gun trigger is then released while the
weld is made. To stop welding, the gun
trigger is pulled again, and when it is released the welding
power source output turns off and the wire feeder stops
feeding wire.

CAUTION

If the arc goes out while welding with trigger interlock
operation, the electrode output from the welding
power source remains energized and the wire feeder
will continue to feed wire until the gun trigger is again
pulled and then released.

------------------------------------------------------------------

B-5

The amperage range is 5 to 700 amps.

TIMER KIT

(Advanced User Interface Only)

The timer kit provides adjustment for preflow, burnback
and postflow.

FLEX FEED™ 74 HT

LED LOCATION

POWER UP SEQUENCE

1. The thermal LED (location See Figure B.3) illuminates
for 2 seconds.

2. If the trigger is already activated, the thermal LED will
quickly blink until the trigger is released.

FIGURE B.4

LED LOCATION

OPERATION

USER INTERFACE:

• User Interface Layout, Advanced

FIGURE B.5

A

• User Interface Layout, Basic

V

FIGURE B.6

B-6

GOUGING KIT

WARNING

ELECTRIC SHOCK can kill.

• If the wire feeder is turned ON with the
process switch in the gouging position,
the welding output will turn ON.

------------------------------------------------------------------

When the gouging kit is installed, a rocker switch is used
to select between wire feeder operation and gouging
operation.

With the switch in the “weld” position, the Flex Feed™ 74
HT functions normally and the output connection for the
gouging torch is OFF.

With the switch in the “gouge” position, the power source
output and gouging connection are ON and the welding
gun is OFF.

(Do Not Switch processes while actively welding or
gouging.)

OPERATIONFLEX FEED™ 74 HT

FIGURE B.7

ELECTRODE IN

WIRE FEED GOUGING
ROCKER SWITCH

GOUGING STUD
(COVER NOT SHOWN)

GOUGING TORCH

CONTACTOR

WIRE DRIVE

CONTACTOR

WIRE DRIVE

WELDING GUN

B-7

FLEX FEED™ 74 HT

OPTIONAL KITS AND

ACCESSORIES

DRIVE ROLL AND WIRE GUIDE KITS

Drive Roll Kits, Steel wires

KP1505-030S .023-.030 (0.6-0.8mm)
KP1505-035S .035 (0.9mm)
KP1505-045S .045 (1.2mm)
KP1505-052S .052 (1.4mm)
KP1505-1/16S 1/16 (1.6mm)
KP1505-1 .035,.045 (0.9, 1.2mm)
KP1505-2 .040 (1.0mm)

Drive Roll Kits, Cored Wires

KP1505-035C .030-.035" (0.8-0.9mm)
KP1505-045C .040-.045" (1.0-1.2mm)
KP1505-052C .052" (1.4mm)
KP1505-1/16C 1/16" (1.6mm)

Includes: 4 Smooth V groove drive
rolls and inner wire guide.

Includes: 4 Knurled drive rolls
and inner wire guide.

ACCESSORIES

Drive Roll Kits, Steel or Cored Wires

KP1505-068 .068-.072" (1.8mm)
KP1505-5/64 5/64" (2.0mm)
KP1505-3/32 3/32" (2.4mm)
KP1505-7/64 7/64" (2.8mm)
KP1505-.120 .120" (3.2mm)

Drive Roll Kits, Hardfacing Wires

KP1505-7/64C 7/64" (2.8mm)

Drive Roll Kits, Aluminum Wire

KP1507-035A .035" (0.9 mm)
KP1507-040A .040" (1.0mm)
KP1507-3/64A 3/64" (1.2mm)
KP1507-1/16A 1/16" (1.6mm)
KP1507-3/32A 3/32" (2.4mm)

Includes: 4 Knurled drive rolls and
inner wire guide.

Includes: 2 Knurled drive rolls, 2
Smooth V groove drive rolls and
inner wire guide.

Includes: 4 polished U groove
drive rolls, outer wire guide and
inner wire guide, pressure door
springs, conduit bushing.

C-1

FLEX FEED™ 74 HT

ACCESSORIES

GUN ADAPTER KITS

K# Description
K3344-1 Gun Adapter Kit,

Lincoln Back-end

K3345-1 Gun Adapter Kit,

standard #4 back-end

K3346-1 Gun Adapter Kit,

Magnum 500 #5 back-end

K3347-1 Gun Adapter Kit,

Miller back-end

K3348-1 Gun Adapter Kit,

Oxo back-end (requires K3345-1)

K3349-1 Gun Adapter Kit,

Fast-Mate (Euro) (requires K3345-1)

C-2

FLEX FEED™ 74 HT

CABLES
K# Description Purpose Image

K1797-xx Control Cable: Male 14 pin to Connects the user interface to

Female 14 pin cable. the wire drive for boom systems.

Connects the wire drive to the
power source on bench systems.

K2335-1,-2 Competitive Equipment Adapter Used to connect the Flex Feed

74 HT to power sources
with 24 VAC.

K1798 Adapter Cable: Female 14 pin Connects the control cable to

to Terminal Strip older power sources that only

have terminal strips.

ACCESSORIES

C-3

FLEX FEED™ 74 HT

GENERAL ACCESSORIES

K# Description Purpose Image
K3974-1 Gouging Contactor Kit Includes contactors and a

switch to change electrode
power from the feeder to a
gouging torch.

K1546-1 Incoming Bushing Use with .025 – 1/16” wires.

for Lincoln Conduit.

K1546-2 Incoming Bushing Use with 1/16” to 1/8” wires

for Lincoln Conduit

ACCESSORIES

K3929-1 Inlet Bushing, quick connect style Included with Flex Feed 74

HT feeders without a wire
reel stand.

K1733-1 Wire Straightener

K1504-1 50-60 lb coil adapter for For use with K3343-1

2 inch spindles heavy duty wire reel stand.

K590-6 Water Connection Kit Includes 4 female quick

disconnects, tubing and
clamps water cooled guns.

K1520-1 42 volt Transformer Kit Converts 110 VAC to

42 VAC.

C-4

FLEX FEED™ 74 HT

K# Description Purpose Image
K283 Portable Digital Wire

Feed Speed Meter

K3342-1 Standard Duty Wire For spools up to 44 lbs.

Reel Stand

K3343-1 Heavy Duty Wire Reel Stand For spools up to 44 lbs

and coils up to 60 lbs.
Includes K3341-1 Lift Bail.

K3341-1 Lift Bail Insulated lift bail for suspending

the wire feeder. Requires either
standard duty or heavy duty wire
reel stand.

K3342-1 Standard Duty Wire For use with 30-40 lb. spools.

Reel Stand

ACCESSORIES

K3343-1 Heavy Duty Wire For use with 50-60 lb. coils and

Reel Stand 30-40 lb spools.

K1634-4 Spool Cover For use with 30-40 lb. spools.

K3340-1 Spool Cover For use with 50-60 lb coils.

KP3103-1 Shielding Gas Filter Protects the gas solenoid and

gun from contaminants.

ACCESSORIES INCLUDED WITH THE FLEX

™

FEED

• Bench models of the Flex Feed™ 74 HT include a 10
foot control cable

• All models include a standard #4 gun adapter.

• Models with the Heavy Duty Wire Reel stand include a
lift bail.

• Models without a wire reel stand include K3929-1 quick
disconnect inlet bushing

74 HT:

C-5

FLEX FEED™ 74 HT

MAINTENANCE

SAFETY PRECAUTIONS

WARNING

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.

• Do not operate with covers, panels or guards removed or
open.

• Only qualified personnel should perform maintenance
work.

----------------------------------------------------------------------

ROUTINE MAINTENANCE

Check weld cables, control cables and gas hoses for
cuts.

Clean and tighten all weld terminals.

PERIODIC MAINTENANCE

Clean the drive rolls and inner wire guide and replace if
worn.

Blow out or vacuum the inside of the feeder.

Inspect the motor brushes every 6 months. Replace if
shorter than 0.5” (12.7mm).

To calibrate the Flex Feed™ 74 HT:

1. Turn power OFF at the welding power source.

2. Remove the (4) screws holding the roof of the wire
feeder to gain access to the pc board.

3. Turn power ON and trigger the Flex Feed 74 HT.

4. Set the WFS knob to 50 in/min and measure the drive
roll rpm. If the drive roll rpm measures 8.9 to 9.2 rpm,
proceed to step 7.

5. Unplug the connector in J2. Insert a shorting plug that
shorts pin 1 and 5. Adjust the WFS knob as required
until drive roll rpm measures:

• 5.93 to 6.13 rpm for 20 tooth pinion gear.

• 8.90 to 9.20 rpm for 30 tooth pinion gear.

6. Remove the shorting plug from J2.

7. Set the WFS knob to 300 in/min. Measure the drive roll
rpm. If the drive roll rpm measures 53.97 to 55.17, pro­ceed to step 10.

8. Unplug the connector in J2. Insert a shorting plug that
shorts pin 1 and 5. Adjust the WFS knob as required
until drive roll rpm measures:

• 35.9 to 36.7 rpm for 20 tooth pinion gear.

• 53.97 to 55.17 rpm for 30 tooth pinion gear.

9. Remove the shorting plug from J2.

10. Set the WFS knob to 500 in/min for the 20 tooth pin-

ion gear or 700 in/min for the 30 tooth pinion gear.
Measure the drive roll rpm. If the drive roll rpm mea­sures 89.9 to 91.9, proceed to step 13.

11. Unplug the connector in J2. Insert a shorting plug

that shorts pin 1 and 5. Adjust the WFS knob as
required until drive roll rpm measures:

• 83.87 to 85.87 rpm for 20 tooth pinion gear.

• 126.32 to 128.32 rpm for 30 tooth pinion gear.

12. Remove the shorting plug from J2.

13. Turn power OFF and reassemble.

CALIBRATION SPECIFICATION

Wire Feed Speed Validation

Calibration matches the scale on the name plate to the
actual wire feed speed. As shipped from the factory, the
wire feeder is calibration for 0.45 (1.2mm) wire.
Calibration of the Flex Feed™ 74 HT may be required
when the p.c. board, the wire feed speed potentiometer
or the motor is replaced or serviced.

D-1

FLEX FEED™ 74 HT

HOW TO USE TROUBLESHOOTING GUIDE

WARNING

Service and Repair should only be performed by Lincoln Electric Factory Trained
Personnel. Unauthorized repairs performed on this equipment may result in
danger to the technician and machine operator and will invalidate your factory
warranty. For your safety and to avoid Electrical Shock, please observe all safety
notes and precautions detailed throughout this manual.

This Troubleshooting Guide is provided to help you locate and repair
possible machine malfunctions. Simply follow the three-step
procedure listed below.

Step 1. LOCATE PROBLEM (SYMPTOM).

Look under the column labeled “PROBLEM (SYMPTOMS)”. This
column describes possible symptoms that the machine may exhibit.
Find the listing that best describes the symptom that the machine is
exhibiting.

Step 2. POSSIBLE CAUSE.

The second column labeled “POSSIBLE CAUSE” lists the obvious
external possibilities that may contribute to the machine symptom.

Step 3. RECOMMENDED COURSE OF

ACTION

This column provides a course of action for the Possible Cause,
generally it states to contact your local Lincoln Authorized Field
Service Facility.

If you do not understand or are unable to perform the Recommended
Course of Action safely, contact your local Lincoln Authorized Field
Service Facility.

TROUBLE SHOOTING

CAUTION

If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact your
Local Lincoln Authorized Field Service Facility for technical troubleshooting assistance before you proceed.

E-1

FLEX FEED™ 74 HT

PROBLEMS

(SYMPTOMS)

Observe all Safety Guidelines detailed throughout this manual

POSSIBLE

CAUSE

RECOMMENDED

COURSE OF ACTION

TROUBLE SHOOTING

The feeder does not power up - no
voltage, no cold feed.

No shielding gas.

Inconsistent wire feeding or wire not
feeding but drive rolls turning.

1. The power source is OFF.

2. The circuit breaker for the wire
feeder on power source have
tripped. (control cable models)

3. The control cable may be loose or
damaged. (control cable models)

1. The gas supply is OFF or empty.

2. The gas hose is cut or crushed.

3. Verify gas is not leaking out
through the gun at the wire drive.
Inspect o-rings.

4. Dirt or debris is in the solenoid.

5. There is a loose solenoid connec­tion.

6. The solenoid has failed.

1. The gun cable is kinked and/or
twisted

2. The wire is jammed in the gun and
cable.

3. The gun liner is dirty or worn.

4. The electrode is rusty or dirty.

5. The contact tip is partially melted
or has spatter.

6. Improper gun liner, tip, drive rolls
and/or inner wire guide.

7. Incorrect pressure on the drive
rolls.

8. The spindle brake is too tight.

9. Worn drive roll.

1. Turn ON the power source.

2. Reset the circuit breakers.

3. Tighten, repair or replace the con­trol cable.

1. Verify the gas supply is ON and
flowing.

2. Route the gas hose so it avoids
sharp corners and make sure
nothing is on top of it. Repair or
replace damaged hoses.

3. Secure the gun into the wire drive.
Replace o-rings on the gun if nec­essary.

4. Apply filtered shop at 80psi to the
solenoid to remove dirt.

5. Remove the cover and check that
all connections are in good condi­tion.

6. Replace the solenoid.

1. Keep the gun cable as straight as
possible. Avoid sharp corners or
bends in the cable.

2. Remove the gun from the wire
feeder and pull the jammed wire
out of the gun and cable.

3. Blow dirt out of the liner with low
pressure (40psi or less). Replace
the liner if worn.

4. Use only clean electrode. Use
quality electrode, like L-50 or L-56
from Lincoln Electric.

5. Replace the contact tip.

6. Verify the proper parts are
installed.

7. Adjust the pressure knob. Most
electrodes feed well at a tension
arm setting of "3".

8. Verify the spool of wire moves
with minimal effort.

9. Replace the drive rolls if worn or
filled with dirt.

CAUTION

If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact your
Local Lincoln Authorized Field Service Facility for technical troubleshooting assistance before you proceed.

E-2

FLEX FEED™ 74 HT

PROBLEMS

(SYMPTOMS)

Observe all Safety Guidelines detailed throughout this manual

POSSIBLE AREAS OF
MISADJUSTMENTS(S)

RECOMMENDED

COURSE OF ACTION

TROUBLE SHOOTING

Wire feed speed consistently oper­ates at the wrong value. The speed
changes when the wire feed speed
knob is adjusted.

The wire feed speed stuck at 200­300 in/min and there is no change
when the wire feed speed knob is
adjusted.

Variable or "hunting" arc.

1. The jumper lead 20 tooth/30 tooth
pinion gear is connected improp­erly.

2. The wrong gear is installed in the
wire drive.

3. The wrong decal was placed on
the case front.

4. The brushes on the motor are
worn.

1. The tachometer is connected
improperly.

2. The tachometer has failed.

1. Wrong size, worn and/or melted
contact tip

2. Worn work cable or poor work
connection.

3. Wrong polarity.

4. The gas nozzle is extended
beyond the contact tip or the wire
stickout is too long.

5. Poor gas shielding on processes
requiring gas.

1. Properly connect the jumper lead
in the harness..

2. Install the proper pinion gear in
the wire drive.

3. Place the correct WFS decal on
the case front.

4. Inspect and replace the motor
brushes.

1. Verify all of the tachometer leads
are properly connected.

2. Replace the motor and tachome­ter assembly.

1. Replace the contact tip.

2. Verify all work and electrode con­nections are tight and that the
cables are in good condition.
Clean/replace as necessary.

3. Adjust the polarity to match the
process.

4. Adjust the gas nozzle and shorten
the stickout to ½ to ¾ inches.

5. Check gas flow and mixture.
Remove or block sources of
drafts.

The wire drive feeds wire at the cor­rect speed but there is not welding
output.

There is gas flow but the feeder
does not feed wire

Poor arc starts with sticking or
"blast-offs", weld porosity, narrow
and ropy looking bead.

1. If a gouging kit is installed, the
gouging switch is in the “gouge”
position

2. If a gouging kit in installed, verify
there is continuity from the elec­trode input to the wire drive.

1. If the advanced user interface is
installed, verify the preflow time
has not been set to a high value

1. Improper procedures or tech­niques.

1. Place the rocker switch in the
welding position.

2. Repair loose connections.
Replace the contactor.

1. Adjust the preflow timer for a
shorter amount of time.

1. See "Gas Metal Arc Welding
Guide" (GS-100)

CAUTION

If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact your
Local Lincoln Authorized Field Service Facility for technical troubleshooting assistance before you proceed.

E-3

FLEX FEED™ 74 HT

DIAGRAMS

F-1

NOTE: This diagram is for reference only. It may not be accurate for all machines covered by this manual. The specific diagram for a particular code is pasted inside the

machine on one of the enclosure panels. If the diagram is illegible, write to the Service Department for a replacement. Give the equipment code number.

FLEX FEED™ 74 HT

DIAGRAMS

1.70

8.19

1.03

1.50

1.50 3.78

11.57

5/16-18 UNC-2B

(8 PLACES)

11.02

2.30

.76

2.003.28

2.00

(4 PLACES)

1/4-20 UNC-2B

.34

(4 PLACES)

5/16-18 UNC-2B

DIMENSION DRAWING FOR WIRE DRIVE HOUSING

18.04

11.58

10.12

10.67

12.39

13.28

8.80

9.94

13.57

4.75

2.25

1.76

.75 9.00

2.99 6.00

3.40

F-2

.57

FLEX FEED™ 74 HT

DIAGRAMS

15.46

11.00

13.28

10.01

7.79

23.62

21.67

DIMENSION DRAWING FOR STANDARD DUTY WIRE REEL STAND

14.08

F-3

FLEX FEED™ 74 HT

DIAGRAMS

9.06

.50

8.36

15.46

11.00

25.17

16.42

12.71

10.56

5.94

27.93

24.45

12.18

DIMENSION DRAWING FOR HEAVY DUTY WIRE REEL STAND

14.33

F-4

NOTES

FLEX FEED™ 74 HT

PARTS LIST FOR

Flex Feed™ 74 HT

P-747P-747

This parts list is provided as an informative guide only.

It was accurate at the time of printing. These pages are only updated on the
Service Navigator DVD and in Lincoln Electrics ofcial Parts Book (BK-34).

When ordering parts, always refer to Lincoln Electrics ofcial Parts Book
(BK-34) for the latest pages.

FLEX FEED™ 74 HT

ILLUSTRATION OF SUB-ASSEMBLIES

4

6

1

2

7

3

5

P-747-AP-747-A

4

FLEX FEED™ 74 HT

06-17-2013

P-747-A.1P-747-A.1

Flex Feed 74 HT

For Codes: 12039, 12040, 12041, 12042, 12045, 12046, 12051 & 12052

Do Not use this Parts List for a machine if its code number is not listed. Contact the Service Department for any
code numbers not listed.

Use the Illustration of Sub-Assemblies page and the table below to determine which sub assembly page and
column the desired part is located on for your particular code machine.

Sub Assembly Item

No.

SUB ASSEMBL Y

PAGE NAME

Miscellaneous Items

PA GE N O.

CODE NO.

12039 1211112•

12040 1131112•

12041 1221111•

P-747-B.2

1

UI Case Front Assembly

P-747-C

2

Wire Drive Assembly

P-747-D

3

Motor & Gearbox Assembly

P-747-E

4

Feedplate & Door Assembly

P-747-F

5

Wire Drive Door

P-747-G

6

Case Side Assemblies & Roof

P-747-H

7

Wire Reel Stand

P-747-J

12042 1141111•

12045 12212111

12046 11412111

12051 12212112

12052 11412112

FLEX FEED™ 74 HT

06-17-2013

P-747-B.2

MISCELLANEOUS ITEMS

(THESE ITEMS ARE NOT ILLUSTRATED)

P-747-B.2

# Indicates a change this printing.

Use only the parts marked “x” in the column under the
heading number called for in the model index page.

DESCRIPTION PART NO. QTY. 123456789

Pinion Gear M18224-2 1 X
WFS Decals M24808 1 X

FLEX FEED™ 74 HT

06-17-2013

NOTES

FLEX FEED™ 74 HT

UI Case Front Assembly

1A

11

10

9

8

3

4

7

5A

5B

2

15

6

5A

P-747-CP-747-C

10

1A

FLEX FEED™ 74 HT

06-17-2013

P-747-C.1

P-747-C.1

# Indicates a change this printing.

Use only the parts marked “x” in the column under the
heading number called for in the model index page.

ITEM DESCRIPTION PART NO. QTY. 123456789

1 UI Case Front Assembly, Includes: G7613-1 1 X •
1 UI Case Front Assembly, Includes: G7613-2 1 • X
1A Case Front (Meters) G7501-1 1 X •
1A Case Front (No Meters) G7501-4 1 • X
2 Nameplate G7580 1 X •
2 Nameplate G7579 1 • X
3 Analog Interface P.C. Board Assembly S29866 1 X •
4 Sems Screw T10082-31 3 X •
5 Plug & Lead Assembly, Includes: S18250-1021 1 X X
5A Potentiometer T10812-119 2 X X
5B Potentiometer Spacer S18280 2 X X
6 Nameplate (Rear) G7580-2 1 X •
7 Timer Kit P.C. Board Assembly M21342-1 1 X •
8 Nut T10940-10 6 X •
9 Lock Washer T9695-5 3 X •
10 1.0” Knob M22778-1 3 X •
11 1.5” Knob M22778-2 2 X X
12 Thread Forming Screw (Not Shown) S9225-99 4 X X
15 UI Trim G6529-1 1 X X

FLEX FEED™ 74 HT

06-17-2013

Wire Drive Assembly

4B

28

11

1A

10A

21A

23

13A

10B

22B

22C

42

41

2

9A

5A

40

6A

6B

5B

4A

3B

3A

3C

17A

14A

16A

19A

17D

8A

18A

26C

22

33

34

26D

26B

25A

26A

15C

15B

16B

15A

16A

29A

22A

18A

16A

14A

33

34

26C

26D

26B

26A

P-747-DP-747-D

25A

8A

5B

5A

16A

40

19A

42

21A

23

22B

10A

13A

15B

15C

15A

6B

6A

3B

3C

3A

22C

22A

FLEX FEED™ 74 HT

06-17-2013

P-747-D.1

P-747-D.1

# Indicates a change this printing.

Use only the parts marked “x” in the column under the
heading number called for in the model index page.

ITEM DESCRIPTION PART NO. QTY. 123456789

Wire Drive Assembly (G7559), Includes: NSS 1 X•••
Wire Drive Assembly (G7559-1), Includes: NSS 1•X••
Wire Drive Assembly (G7559-2), Includes: NSS 1 ••X•

Wire Drive Assembly (G7559-3), Includes: NSS 1 •••X
1A Wire Drive Base Assembly L16537-1 1 XXXX
1B Speed Nut (Not Shown) T11525-8 2 XXXX
2 Bushing T12380-10 4 XXXX
3A Mounting Foot S29507 4 XXXX
3B Thread Forming Screw S9225-100 12 XXXX
3C Plain Washer S926-182 12 XXXX
4A Plug Button T10397-20 1 XXXX
4B Plug Button T10397-27 1 XXXX
5A Rocker Switch T10800-68 1 XXXX
5B Rocker Switch Boot S28672-1 1 XXXX
6 Main Harness, Includes: G7609 1 XXXX
6A Connector (5 Socket) (P13) S12021-66 1 XXXX
6B Self Tapping Screw S8025-118 2 XXXX
8A Relay S27028 1 X • X •
8A Relay S27028 2 • X • X
8B Self Tapping Screw (Not Shown) S8025-98

As Req

XXXX
9A Diode Bridge T13637-6 1 XXXX
9B #10-24 HLN (Not Shown) T9187-13 1 XXXX
10A LED Lens, Clear, Includes: S23093-1 1 XXXX
10B Retaining “O” Ring S23094-1 1 XXXX
11 Rocker Switch T10800-76 1 XXXX
12 Rocker Switch (Not Shown) T10800-72 1 • X • X
13A Control Cable M21501-3 1 XXXX
13B Reducing Washer (Not Shown) S24014-1 2 XXXX
13C Conduit Locknut (Not Shown) T14370-2 1 XXXX
14A Output Terminal Assembly S16656-4 1 XXXX
14B Thread Forming Screw (Not Shown) S9225-99 2 XXXX
15A Output Stud Cover M20007 1 XXXX
15B Thread Forming Screw S9225-68 2 XXXX
15C Output Stud Cover Plate S24669 1 XXXX
16A Contactor Assembly S29859 2 • X • X
16B #10-24 x 2.00 HHMS CF000391 4 • X • X
16C Lock Washer (Not Shown) T9695-1 4 • X • X
16D #10-24 SQN (Not Shown) CF000154 4 • X • X
17A 5/16-18 x 1.25 SHCS T9447-20 2 • • X •
17B Lock Washer (Not Shown) E106A-3 2 • • X •
17C Plain Washer (Not Shown) S9262-159 2 • • X •
17D Insulator Bushing S22732-1 2 • • X •
17E Spacer (Not Shown) S22732-2 4 • • X •
18A Bus Bar S29542-2 1 • X X X
18B 1/2-13 x 1.00 HHCS (Not Shown) CF000021 1 XXXX
18C Lock Washer (Not Shown) E106A-15 1 XXXX
18D Plain Washer (Not Shown) S9262-1 1 XXXX
19A Current Transducer S18504-10 1 • • X X
19B Thread Forming Screw (Not Shown) S9225-52 1 • • X X
19C Lock Washer (Not Shown) T4291-A 1 • • X X
19D Plain Washer (Not Shown) S9262-3 1 • • X X

NSS - Not Sold Separately

FLEX FEED™ 74 HT

06-17-2013

P-747-D.2

P-747-D.2

# Indicates a change this printing.

Use only the parts marked “x” in the column under the
heading number called for in the model index page.

ITEM DESCRIPTION PART NO. QTY. 123456789

21A Motor Bottom Support L16384-1 1 XXXX
21B Speed Nut (Not Shown) T11525-8 4 XXXX
22 Motor & Gearbox Assembly See P-747-E 1 XXXX
22A Insulator T11267-A 3 XXXX
22B Insulator T11267-B 3 XXXX
22C Thread Forming Screw S9225-66 3 XXXX
22D Lock Washer (Not Shown) E106A-2 3 XXXX
23 Thread Forming Screw (Not Shown) S9225-99 4 XXXX
25A Motor Top Support L16384-2 1 XXXX
25B Speed Nut (Not Shown) T11525-8 2 XXXX
26A Insulator T11267-A 3 XXXX
26B Insulator T11267-B 3 XXXX
26C Thread Forming Screw S9225-66 3 XXXX
26D Lock Washer E106A-2 3 XXXX
27 Thread Forming Screw (Not Shown) S9225-99 4 XXXX
28 Plug Button T10397-19 2 XXXX
29A Solenoid Valve M17294-8 1 XXXX
29B Plain Washer (Not Shown) S9262-149 1 XXXX
29C Conduit Lock Nut (Not Shown) T14370-1 1 XXXX
30 Gas Hose (Not Shown) T10642-265 1 XXXX
31 Hose Clamp (Not Shown) T13777-8 2 XXXX
33 Bushing T12380-3 1 XXXX
34 Plug Button T10397-7 1 XXXX
40 Decal (M24809-3) (Part of M24809) NSS 1 XXXX
41 Decal (M24809-4) (Part of M24809) NSS 1 XXXX
42 Decal (M24809-5) (Part of M24809) NSS 1 XXXX
43 Contactor Harness (Not Shown) M24980 1 XXXX

FLEX FEED™ 74 HT

06-17-2013

NOTES

FLEX FEED™ 74 HT

Motor & Gear Box Assembly

1

3

3

2

10

11

13

12

15

20A

16F

16E

16H

16G

16A

16D

16K

16J

16L

16B

16C

20B

20C

20D

16

17

6

7

4

8

9

5

P-747-EP-747-E

10

12

20B

20C

20D

20A

15

16

16H

16E

16G

16F

16A

16D

16J

16L

16K

FLEX FEED™ 74 HT

16C

16B

06-17-2013

P-747-E.1

P-747-E.1

# Indicates a change this printing.

Use only the parts marked “x” in the column under the
heading number called for in the model index page.

ITEM DESCRIPTION PART NO. QTY. 123456789

Motor & Gearbox Assembly, Includes: G7562-2 1 X
1 Gearbox, Machined G7449-1 1 X
2 Needle Bearing S10116-1 1 Xɤ
3 Dowel Pin T13942-15 2 X
4 Output Shaft M18161-1 1 X
5 Woodruff Key #304 1 X
6 Bearing M9300-79 1 X
7 Snap Ring S9776-23 1 X
8 Output Gear S15859 1 X
9 External Snap Ring T8856-2 1 X
10 Reduction Shaft S15861 1 X
11 Reduction Gear S15860-5 1 X
12 Woodruff Key #304 1 X
13 External Snap Ring T8856-2 1 X
15 Gasket M24897 1 X
16 Motor, Tach & Cover Asbly (M24901-1), Includes: NSS 1X
16A Drive Motor L16325 1 X
16B Pinion Gear S17980-4 1 X
16C Roll Pin T9967-33 1 X
16D Ring Magnet S18011-4 1 X
16E Sems Screw T10082-12 1 X
16F Encoder S20374-4 1 X
16G Lock Washer E106A-13 2 X
16H Socket Heat Cap Screw T9447-119 2 X
16J Gerbox Cover G7452-1 1 X
16K Needle Bearing S10116-4 2 X
16L Thread Forming Screw S9225-99 3 X
16M Brush & Cap Kit (Not Shown) S29814 1 X
17 Thread Forming Screw S9225-99 6 X
18 Woodruff Key (Not Shown) #404 1 X
20A Pinion (Ext. Output) M18223-2 2 X
20B Thread Forming Screw S9225-30 2 X
20C Lock Washer E106A-1 2 X
20D Plain Washer S9262-158 2 X

NSS - Not Sold Separately

FLEX FEED™ 74 HT

06-17-2013

Feedplate & Door Assembly

26

1A

25

2

3

14

4

30A

30B

30C

21

24A

6

28

5

8

7

35

P-747-FP-747-F

30A

30B

30C

21

24A

25

26

1A

14

FLEX FEED™ 74 HT

06-17-2013

P-747-F.1

P-747-F.1

# Indicates a change this printing.

Use only the parts marked “x” in the column under the
heading number called for in the model index page.

ITEM DESCRIPTION PART NO. QTY. 123456789

1 Feed Plate & Door Asbly (G3104-21), Includes NSS 1XX
1A Feedplate Assembly , G3076-1 1 1 X X
2 Insulator Bushing S22732-1 3 X X
3 5/16-18 x 1.50 SHCS T9447-110 2 X X
4 Feed Plate Insulator G7578 1 X X
5 Clamp S22655 1 X X
6 1/4-20 x .62 SHCS T9447-120 1 X X
7 1/4-20 x 1.25 SHCS T9447-121 1 X X
8 Door Assembly (L10193-9) See P-747-G 1 X X
9 Set Screw (Not Shown) S11604-22 1 X X
10 Insulating Bushing (Not Shown) S16860-1 2 X X
11 Hinge Pin (Not Shown) S22756 1 X X
12 Set Screw (Not Shown) S11604-64 2 X X
14 Wire Guide Asbly (Outer) KP2071-1 1 X X
21 Right Gun Adapter Assembly K3345-1 1 X X
24A Thread Forming Screw S9225-51 1 X X
24B Lock Washer (Not Shown) T4291-A 1 X X
24C Plain Washer (Not Shown) S9262-3 1 X X
25 Sems Screw T10082-27 1 X X
26 Molded Hand Screw T13858-6 1 X X
28 Gun Adapter Cover, Right G7644-2 1 X X
30A 1/2-13 x 1.50 HHCS CF000052 1 X X
30B Lock Washer E106A-15 1 X X
30C Plain Washer S9262-80 1 X X
35 Bushing S23124-8 1 X •
35 Bushing M18947-1 1 • X

NSS - Not Sold Separately

FLEX FEED™ 74 HT

06-17-2013

P-747-GP-747-G

3

1A

1

14

12

11

10

13

7

15

6

4

5

10

9

8

Wire Drive Door

3

1A

15

14

12

10

10

FLEX FEED™ 74 HT

06-17-2013

P-747-G.1

P-747-G.1

# Indicates a change this printing.

Use only the parts marked “x” in the column under the
heading number called for in the model index page.

ITEM DESCRIPTION PART NO. QTY. 123456789

Wire Drive Door, Includes: L10193-9 1 X
1 Door Machining, Includes: L10092-4 1 X
1A Pin M8809-135 4 X
3 Decal S22900-1 1 X
4 Pressure Arm M18183-3 2 X
5 Wear Plug S22734 2 X
6 Spring Retaining Rod S22662 1 X
7 Compression Spring T11862-54 2 X
8 #6-32 x 1.00 SHCS T9447-100 2 X
9 Indicator S22899 1 X
10 Plastic Thrust Washer T14052 4 X
11 Thrust Washer T14043 1 X
12 Adjustment Knob S22674 1 X
13 Door Insert G7593 1 X
14 Thread Forming Screw S9225-99 1 X
15 Warning Decal S25815-1 1 X

FLEX FEED™ 74 HT

06-17-2013

Case Side Assemblies & Roof

7

6

8A

1A

2

3

8B

9

13

15B

11

10

5A

8C

15A

12A

16A

17

16B

16C

15D

15C

P-747-HP-747-H

8B

13

1A

16A

12A

15B

16B

16C

15D

15C

15A

FLEX FEED™ 74 HT

06-17-2013

P-747-H.1

P-747-H.1

# Indicates a change this printing.

Use only the parts marked “x” in the column under the
heading number called for in the model index page.

ITEM DESCRIPTION PART NO. QTY. 123456789

1 Left Case Side & Decals Assembly, Includes: G7691 1 X •
1 Left Case Side & Decals Assembly, Includes: M24877 1 • X
1A Left Case Side G7488-3 1 X •
1A Left Case Side G7487-1 1 • X
2 Gouging Switch Decal (S29857-2) (Part of S29857) NSS 1X•
3 Logo Decal S11893-13 2 X •
3 LECO Logo Decal S27368-2 2 • X
5A Output Terminal Assembly S16656-4 1 X •
5B Thread Forming Screw (Not Shown) S9225-99 2 X •
6 Family Name Decal (M24944-1) (Part of M24944) NSS 1XX
7 Family Name Decal (M24944-2) (Part of M24944) NSS 1XX
8A Output Stud Cover M20007 1 X •
8B Output Stud Cover Plate S25669 1 X •
8C Thread Forming Screw S9225-68 2 X •
9 Gouging Switch Decal (S29857-1) (Part of S29857) NSS 1X•
10 Output Terminal Decal (S29857-3) (Part of S29857) NSS 1X•
11 Output Terminal Decal (S29857-4) (Part of S29857) NSS 1X•
12A 1/2-13 x 1.00 HHCS (Not Shown) CF000021 1 X •
12B Lock Washer (Not Shown) E106A-15 1 X •
12C Plain Washer (Not Shown) S9262-80 1 X •
13 Thread Forming Screw S9225-99 2 X X
15 Right Case Side & Decals Assembly, Includes: M24878 1 X X
15A Right Case Side G7488-1 1 X X
15B Decal (M24809-1) (Part of M24809) NSS 1XX
15C Family Name Decal (M24944-1) (Part of M24944) NSS 1XX
15D Family Name Decal (M24944-2) (Part of M24944) NSS 1XX
15E Decal (M24809-2) (Part of M24809) (Not Shown) NSS 1XX
15F Thread Forming Screw (Not Shown) S9225-99 2 X X
16A Roof G7486-1 1 X X
16B Wire Drive P.C. Board S30122 1 X X
16C #10-24 HLN T9187-13 4 X X
16D Thread Forming Screw (Not Shown) S9225-99 4 X X
17 Warning Decal S20601-5 1 X X

NSS - Not Sold Separately

FLEX FEED™ 74 HT

06-17-2013

Wire Reel Stand (Right & Left)

1C

6B

6C

6D

2

4A 4B

4C

3A

3B

7

7

8

9

5

6A

7

7

10

9

13

12

11

P-747-JP-747-J

6D

6C

6B

1C

3B

3A

4C

6A

10

13

FLEX FEED™ 74 HT

06-17-2013

P-747-J.1

P-747-J.1

# Indicates a change this printing.

Use only the parts marked “x” in the column under the
heading number called for in the model index page.

ITEM DESCRIPTION PART NO. QTY. 123456789

1A Wire Reel Stand (G7500-2), Includes: K3342-1 1 X •
1B Wire Reel Stand (G7585-2), Includes: K3343-1 1 • X
1C Mast Welded Assembly G7499 1 X •
1C Mast Welded Assembly G7584 1 • X
2 Outrigger L16322 1 X X
3A 1/4-20 SS Screw S24739-31 4 X X
3B 1/4-20 HLN T9187-16 4 X X
4A Bumper T14882-4 2 X X
4B Plain Washer S9262-27 2 X X
4C Thread Forming Screw S9225-100 2 X X
5 Lift Bail Final Assembly K3341-1 1 • X
6A Spindle Shaft M21542-2 1 X X
6B Plain Washer S9262-120 2 X X
6C Lock Washer E106A-4 2 X X
6D 3/8-16 x 1.25 HHCS CF000105 2 X X
7 Friction Washer S17435-3

As Req

XX
8 Spindle L10560-2 1 X X
9 Keyed Washer T12965-2

As Req

XX
10 Star Washer S27180 1 • X
11 Spring T11862-14 1 X X
12 Thumb Screw T14813-A 1 X X
13 Retaining Collar Assembly S23811 1 X X
15A 5/16-18 x .75 HHCS (Not Shown) CF000040 4 X X
15B Plain Washer (Not Shown) S9262-30 4 X X
15C Lock Washer (Not Shown) E106A-3 4 X X

FLEX FEED™ 74 HT

06-17-2013

CUSTOMER ASSISTANCE POLICY

The business of The Lincoln Electric Company is manufacturing and
selling high quality welding equipment, consumables, and cutting
equipment. Our challenge is to meet the needs of our customers and
to exceed their expectations. On occasion, purchasers may ask
Lincoln Electric for advice or information about their use of our
products. We respond to our customers based on the best information
in our possession at that time. Lincoln Electric is not in a position to
warrant or guarantee such advice, and assumes no liability, with
respect to such information or advice. We expressly disclaim any
warranty of any kind, including any warranty of fitness for any
customer’s particular purpose, with respect to such information or
advice. As a matter of practical consideration, we also cannot assume
any responsibility for updating or correcting any such information or
advice once it has been given, nor does the provision of information
or advice create, expand or alter any warranty with respect to the sale
of our products.

Lincoln Electric is a responsive manufacturer, but the selection and
use of specific products sold by Lincoln Electric is solely within the
control of, and remains the sole responsibility of the customer. Many
variables beyond the control of Lincoln Electric affect the results
obtained in applying these types of fabrication methods and service
requirements.

Subject to Change – This information is accurate to the best of our
knowledge at the time of printing. Please refer to
www.lincolnelectric.com for any updated information.