Lincoln Electric FLEX FEED 74 HT User manual

Operator’s Manual
FLEX FEED ™74 HT
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Authorized Service and Distributor Locator:
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IM10163 | Issue Date Nov-13
© Lincoln Global, Inc. All Rights Reserved.
For use with machines having Code Numbers:
12039 - 12052
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 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 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

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. PACE-
MAKER 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.
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
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 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
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
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

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 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.
Refer to
http://www.lincolnelectric.com/safety
for additional
safety information.
5
SAFETY
Welding Safety
Interactive Web Guide
for mobile devices
Get t he f r ee mobi l e app
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6
TABLE OF CONTENTS
FLEX FEED™ 74 HT
Page
Product Description ......................................................................................................................7
Installation.......................................................................................................................Section A
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 .....................................................................A-3
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 ........................................................................................................A-23
Shielding Gas..............................................................................................................A-24
Loading Spools of Wire .....................................................................................A-25, A-26
Wire Reel Stands ........................................................................................................A-27
Electrical Installation ...................................................................................................A-28
Non Lincoln Equipment Adapter .................................................................................A-29
Relay Connections......................................................................................................A-30
Operation.........................................................................................................................Section B
Graphic Symbols..................................................................................................................B-1
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 ........................................................................................B-5
Thermal LED ........................................................................................................................B-5
Cold Feed.............................................................................................................................B-5
Gas Purge ............................................................................................................................B-5
Digital Meters .......................................................................................................................B-5
Timer Kit...............................................................................................................................B-5
Power Up Sequence ............................................................................................................B-6
User Interface.......................................................................................................................B-6
Gouging Kit...........................................................................................................................B-7
Accessories.....................................................................................................Section C
Optional Kits and Accessories...............................................................................C-1
Gun Adapter Kits.............................................................................................C-2
Cables..........................................................................................................................
C-3
General Accessories ...........................................................................................................
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

7
PRODUCT DESCRIPTION
FLEX FEED™ 74 HT
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, capa-
ble 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 reli-
ability 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 dis-
play 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.

A-1
INSTALLATIONFLEX FEED™ 74 HT
TECHNICAL SPECIFICATIONS – FLEX FEED™ 74 HT (K3883-XX)
TEMPERATURE RANGE
OPERATION: -40°F to 104°F (-40°C to 40°C)
STORAGE: -40°F to 122°F (-40°C to 50°C)
INPUT VOLTAGE and CURRENT
HEIGHT WIDTH DEPTH WEIGHT
Wire 11.1 Inches 13.6 Inches 13.3 Inches 36 lbs.
Drive ( 294mm) (345mm) (337mm) (16.3kg)
(only)
PHYSICAL DIMENSIONS
VOLTAGE
24 – 42 VAC
NOTES
Wire Drive
INPUT AMPERES
10A
RATED OUTPUT @ 104°F (40°C)
No Gouging Kit
With Gouging Kit
Wire Drive
Wire Drive
Gouging Stud
DUTY CYCLE
60%
60%
30%
INPUT AMPERES
600 Amps
500 Amps
600 Amps
GEARING - WIRE FEED SPEED RANGE-WIRE SIZE
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)
.035” - .120”
(0.9 – 3.0 mm)
.035 – 5/64”
(0.9 – 2.0 mm)
PINION GEAR
20 tooth*
30 tooth
GMAW FCAW
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.
WIRE SIZES
IP2X for the wire drive and user interface.

A-2
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
MODEL NUMBERS FOR BASIC AND ADVANCED USER INTERFACE

A-3
INSTALLATION
FLEX FEED™ 74 HT
SAFETY PRECAUTIONS
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.
-------------------------------------------------------------------
WARNING
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.
INNER WIRE DRIVE
DIVE ROLLS
OUTER WIRE DRIVE
FIGURE A.1

A-4
INSTALLATIONFLEX FEED™ 74 HT
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
surface, lubrication and hardness. Too much pressure
may crush the wire or cause "birdnesting", but too lit-
tle 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.
PRESSURE
ADJUST KNOB
FIGURE A.2

A-5
INSTALLATIONFLEX FEED™ 74 HT
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.
3. With a 3/4” wrench, remove the bolt holding the
electrode lead to the gun adapter.
SCREW
GUN
ADAPTER
COVER
ELECTRODE
LEAD
BOLT
FIGURE A.3
FIGURE A.4

A-6
INSTALLATIONFLEX FEED™ 74 HT
4. Use a 1/8” hex key to loosen the set screw securing
the gun adapter.
SET SCREW
GUN ADAPTER
FIGURE A.5

A-7
INSTALLATIONFLEX FEED™ 74 HT
5. Remove the sense lead with a Phillips screw driver.
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.
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
SENSE
LEAD
SET SCREW
GUIDE TUBE
FIGURE A.6
FIGURE A.7

A-8
INSTALLATIONFLEX FEED™ 74 HT
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
12. Assemble the gun adapter cover and secure with the
screw. FIGURE A.9
SCREW
GUN
ADAPTER
COVER
KEEP TERMINAL AND
LEAD VERTICAL.
ELECTRODE
LEAD
BOLT

A-9
INSTALLATIONFLEX FEED™ 74 HT
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.
3. With a 3/4” wrench, remove the bolt holding the
electrode lead to the gun adapter.
SCREW
GUN
ADAPTER
COVER
ELECTRODE
LEAD
BOLT
FIGURE A.10
FIGURE A.11

A-10
INSTALLATIONFLEX FEED™ 74 HT
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.
KEEP TERMINAL AND
LEAD VERTICAL.
ELECTRODE
LEAD
BOLT
FIGURE A.12

A-11
INSTALLATIONFLEX FEED™ 74 HT
6. Assemble the gun adapter cover and secure with the
screw.
7. Assemble the gas hose to the Oxo or FastMate gun
adapter.
8. Select the appropriate guide tube and secure with the
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
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.
SCREW
GUN
ADAPTER
COVER
SET SCREW
GUIDE TUBE
FIGURE A.13
FIGURE A.14

A-12
INSTALLATIONFLEX FEED™ 74 HT
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.
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.
HINGE PIN
SET SCREW
FIGURE A.15
FIGURE A.16

A-13
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
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
Decals are located in the literature of the feeder.
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
3. Rotate the wire drive to the desired position and tighten
the screw.
(2) SOCKET HEAD
CAP SCREWS
SOCKET HEAD CAP SCREW