Lincoln Electric Magnum PRO Curve HDE 250 User manual

Operator’s Manual
Magnum PRO
®
Curve HDE 250, 350,
450 & 550
Register your machine:
www.lincolnelectric.com/register
Authorized Service and Distributor Locator:
www.lincolnelectric.com/locator
IM10551-B | Issue D ate Mar-21
© Lincoln Global, Inc. All Rights Reserved.
For use with Code Numbers:
K4531-[ ]
K4532-[ ]
K4533-[ ]
K4534-[ ]
Save for future reference
Date Purchased
Code: (ex: 10859)
Serial: (ex: U1060512345)

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

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

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

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

2
TABLE OF CONTENTSMAGNUM PRO®CURVE HDE 250, 350, 450 & 550
INSTALLATION .............................................................................................................................................SECTION A
GENERAL DESCRIPTION.............................................................................................................................................A-1
TECHNICAL SPECIFICATIONS .....................................................................................................................................A-1
WHATS INCLUDED.....................................................................................................................................................A-5
CONNECTOR KIT INSTALLATION TO GUN CABLE ........................................................................................................A-6
K466-1 AND K466-8 INSTALLATION (FOR LINCOLN FEEDERS)...................................................................................A-6
K466-2 INSTALLATION (FOR TWECO ADAPTED FEEDERS)..........................................................................................A-6
K466-3 INSTALLATION (FOR MILLER FEEDERS) .........................................................................................................A-6
K466-6 AND K466-10 INSTALLATION (WIREMATIC AND LINCOLN 10 SERIES FEEDERS) ............................................A-6
K613-1 INSTALLATION ..............................................................................................................................................A-6
K613-3 INSTALLATION ..............................................................................................................................................A-6
K613-2, K613-7 INSTALLATION.................................................................................................................................A-6
K613-6 INSTALLATION ..............................................................................................................................................A-6
LINER INSTALLATION AND TRIMMING INSTRUCTIONS................................................................................................A-7
ROTATING THE GUN TUBE .........................................................................................................................................A-7
CONTACT TIP AND GAS NOZZLE INSTALLATION.........................................................................................................A-7
CONNECTION TO FEEDER ..........................................................................................................................................A-7
CONNECTION TO LINCOLN FEEDERS..........................................................................................................................A-7
CONNECTION TO TWECO ADAPTED FEEDERS ............................................................................................................A-7
CONNECTION TO MILLER FEEDERS............................................................................................................................A-8
CONNECTION TO POWER MIG®SERIES, POWER WAVE®...........................................................................................A-8
CONNECTION TO LINCOLN 10 SERIES FEEDERS.........................................................................................................A-8
OPERATION ................................................................................................................................................SECTION B
ELECTRODES AND EQUIPMENT..................................................................................................................................B-1
MAKING A WELD........................................................................................................................................................B-1
AVOIDING WIRE FEEDING PROBLEMS ........................................................................................................................B-1
ACCESSORIES ..............................................................................................................................................SECTION C
MAINTENANCE .............................................................................................................................................SECTION D
REMOVAL, INSTALLATION AND TRIMMING GUN LINERS.............................................................................................D-1
GUN TUBES AND NOZZLES........................................................................................................................................D-1
GUN CABLES ............................................................................................................................................................D-1
CABLE REPAIR...........................................................................................................................................................D-1
GUN TUBE END REPAIR ............................................................................................................................................D-1
WIRE FEEDER END REPAIR ......................................................................................................................................D-3
WIRE FEEDER END REPAIR (K2952-1-FM-116A)........................................................................................................D-4
TROUBLESHOOTING......................................................................................................................................SECTION E
PARTS LIST ...............................................................................................................PARTS.LINCOLNELECTRIC.COM
CONTENT/DETAILS MAY BE CHANGED OR UPDATED WITHOUT NOTICE. FOR MOST CURRENT INSTRUCTION MANUALS, GO
TO PARTS.LINCOLNELECTRIC.COM.

A-1
INSTALLATIONMAGNUM PRO®CURVE HDE 250, 350, 450 & 550
GENERAL DESCRIPTION
The MAGNUM®PRO CURVE HDE 250, 350, 450 & 550 Amps guns
and cable assemblies have been designed to meet IEC 60974-7
specification for welding with steel electrode using the GMAW (gas
metal arc welding) and gas-shielded FCAW (flux- cored arc
welding) processes. The MAGNUM®PRO CURVE HDE guns are
manually guided and air cooled.
MAGNUM®PRO CURVE HDE 250, 350, 450 & 550 guns are not
factory equipped with a feeder end connector.
The Magnum PRO Curve HDE guns can be connected to the
following feeders by using the connectors outlined in the table
below.
For best Results when welding mild and steels, it is recommended
that L-50 or L-56 Lincoln solid wire electrodes be used for the
GMAW process and OS70 or OS71 Lincoln UltraCore®or
Outershield®electrodes
Do not touch electrically live parts such as output terminals
or internal wiring
WARNING
TABLE A.1 - GUN CONNECTOR KITS
Manufacturer Wire Feeder Model
K466 Connector Kits
(accept K44-series liners)
K613 Connector Kits
(accept K45-series liners)
Lincoln
Electric®
LN-7 Series, LN-8, LN-9, LN-25
(Up to .052 in./1.4 mm wire,
LN-23P
K466-1 K613-1
LN-8, LN-9 Series, LN-25 (1/16
in./1.6 mm and larger), LN-23P K466-8 K613-6
LF-72, LF-74 Series, Flex Feed
74 HT, Flex Feed 84, LN-25 PRO,
LN-25X, Activ8, Activ8x
K466-10 K613-7
Power Feed™ 10, 10M, 25M,
and 84 K466-10 K613-7
POWER MIG®® Series and Power
Wave®C300 K466-6 N/A
Tweco®
Adapted No. 2, No. 3, No. 4 Guns K466-2 K613-2
Miller®Intellimatic, Sidekick, D-51A,
Porto-Mig Millermatic 130, 200,
MM-35, S-42GL, S-52A, Swing
Arc-Dual, Swing Arc-Single, S-
32S, 52D, 54D, 54E, 60 Series
K466-3 K613-3

A-2
INSTALLATIONMAGNUM PRO®CURVE HDE 250, 350, 450 & 550
TECHNICAL SPECIFICATIONS
MAGNUM
®
PRO CURVE HDE 250 & 350 GUNS
K4531-[] 100% DUTY CYCLE AT 250 AMPS WITH CO2 & MIXED GAS
K4532-[] 100% DUTY CYCLE AT 350 AMPS WITH CO2 & MIXED GAS
Description
Product
Number
Gun
Cable
Length
(m)
Wire size In
(mm)
Contact Tips
Standard
Duty
Gas
Diffuser
Assembly Gas Nozzle Insulator Cable Liner
Gun Tube
60°
Gun Tube
45°
K4531-1 10 ft
(3.0) .035-5/64 in (0.9-2.0 mm)
KP2744-035
KP2744-045 KP2746-1 KP2742-1-62R KP2773-2 KP44-3545-15
KP4693-60 KP4693-45
K4531-2 15 ft
(4.5) .035-5/64 in (0.9-2.0 mm)
K4531-3 20 ft
(6.1) .035-5/64 in (0.9-2.0 mm)
K4531-4 25 ft
(7.6) .035-5/64 in (0.9-2.0 mm)
K4532-1 10 ft
(3.0) .035-5/64 in (0.9-2.0 mm)
KP4694-60 KP4694-45
K4532-2 15 ft
(4.5) .035-5/64 in (0.9-2.0 mm)
K4532-3 20 ft
(6.1) .035-5/64 in (0.9-2.0 mm)
K4532-4 25 ft
(7.6) .035-5/64 in (0.9-2.0 mm)
MAGNUM® PRO CURVE HDE 450 & 550 GUNS
K4533-[] 100% DUTY CYCLE AT 450 AMPS WITH CO2 & MIXED GAS
K4534-[] 100% DUTY CYCLE AT 550 AMPS WITH CO2 & 500 AMPS WITH MIXED GAS
Description
Product
Number
Gun
Cable
Length
(m)
Wire size In
(mm)
Contact Tips
Standard
Duty
Gas
Diffuser
Assembly Gas Nozzle Insulator Cable Liner
Gun Tube
60°
Gun Tube
45°
K4533-1 10 ft
(3.0) .035-5/64 in (0.9-2.0 mm)
KP2745-035
KP2745-045 KP2747-1 KP2743-1-62R KP2773-1 KP44-3545-15
KP4695-60 KP4695-45
K4533-2 15 ft
(4.5) .035-5/64 in (0.9-2.0 mm)
K4533-3 20 ft
(6.1) .035-5/64 in (0.9-2.0 mm)
K4533-4 25 ft
(7.6) .035-5/64 in (0.9-2.0 mm)
K4534-1 10 ft
(3.0) .035-1/8 in (0.9-3.2 mm)
KP4696-60 KP4696-45
K4534-2 15 ft
(4.5) .035-1/8 in (0.9-3.2 mm)
K4534-3 20 ft
(6.1) .035-1/8 in (0.9-3.2 mm)
K4534-4 25 ft
(7.6) .035-1/8 in (0.9-3.2 mm)
KP42-3035-15

A-3
INSTALLATIONMAGNUM PRO®CURVE HDE 250, 350, 450 & 550
TECHNICAL SPECIFICATIONS
M AGNUM ® PRO CURV E HDE READY PAK 250 & 350 GUNS
K4531-[] 100% DUTY CYCLE AT 250 AMPS WITH CO2 & MIXED GAS
K4532-[] 100% DUTY CYCLE AT 350 AMPS WITH CO2 & M IXED GAS
Description Gun Contact Tips Gas
Cable Wire size In Gun Tube
Product Length Standard Diffuser Gas Nozzle Insulator Cable Liner
Number (m) (mm) Duty Assembly 60°
K4531-2-10-45
15 f t .035-5/64 in
KP2744-045 KP2746-1 KP2742-1-62R KP2773-2
KP42-4045-15 KP4693-60
(4.5) (0.9-2.0 mm)
K4531-2-3-45
15 f t .035-5/64 in
(4.5) (0.9-2.0 mm)
K4531-2-6-45
15 f t .035-5/64 in
(4.5) (0.9-2.0 mm)
K4532-2-10-45
15 f t .035-5/64 in
KP44-3545-15
KP4694-60
(4.5) (0.9-2.0 mm)
K4532-2-3-45
15 f t .035-5/64 in
(4.5) (0.9-2.0 mm)
K4532-2-6-45
15 f t .035-5/64 in
(4.5) (0.9-2.0 mm)
K4532-2-1-45
15 f t .035-5/64 in
(4.5) (0.9-2.0 mm)
K4532-2-10-116
15 f t .035-5/64 in
KP2745-116 KP2747-1 KP2743-1-62R KP2773-1
KP44-116-15
(4.5) (0.9-2.0 mm)
K4532-2-3-116
15 f t .035-5/64 in
(4.5) (0.9-2.0 mm)
K4532-2-6-116
15 f t .035-5/64 in
(4.5) (0.9-2.0 mm)
K4532-2-1-116
15 f t .035-5/64 in
(4.5) (0.9-2.0 mm)
K4532-4-10-116
25 f t .035-5/64 in
KP44-116-25
(7.6) (0.9-2.0 mm)
K4532-4-3-116
25 f t .035-5/64 in
(7.6) (0.9-2.0 mm)
K4532-4-6-116
25 f t .035-5/64 in
(7.6) (0.9-2.0 mm)
K4532-4-1-116
25 f t .035-1/8 in
(7.6) (0.9-3.2 mm)

A-4
INSTALLATIONMAGNUM PRO®CURVE HDE 250, 350, 450 & 550
TECHNICAL SPECIFICATIONS
MAGNUM® PRO CURVE HDE READY PAK 450 & 550 GUNS
K4533-[] 100% DUTY CYCLE AT 450 AMPS WITH CO2 & MIXED GAS
K4534-[] 100% DUTY CYCLE AT 550 AMPS WITH CO2 & 500 AMPS WITH MIXED GAS
Description Gun Contact Tips
Gas Diffuser
Assembly Gas Nozzle Insulator Cable Liner
Cable Wire size In Gun Tube
Product Length Standard
Number (m) (mm) Duty 60°
K4533-2-10-564
15 f t .035-5/64 in
KP2745-564
KP2747-1 KP2743-1-62R KP2773-1
KP44-564-15 KP4695-60
(4.5) (0.9-2.0 mm)
K4533-2-3-564
15 f t .035-5/64 in
(4.5) (0.9-2.0 mm)
K4533-2-7-332
15 f t .035-5/64 in
KP2745-332 KP45H-332-15
KP4696-60SN
(4.5) (0.9-2.0 mm)
K4533-2-3-332
15 f t .035- 5/64 in
(4.5) (0.9-2.0 mm)
K4534-2-7-332
15 f t .035-1/8 in
KP4696-60
(4.5) (0.9-2.0 mm)
K4534-2-3-332
15 f t .035- 1/8 in
(4.5) (0.9- 3.2 mm)

A-5
INSTALLATIONMAGNUM PRO®CURVE HDE 250, 350, 450 & 550
INSTALLATION
Read this entire installation section before you
start installation.
SAFETY PRECAUTIONS
ELECTRIC SHOCK can kill.
• Do not touch electrically live parts such
as output terminals or internal wiring.
• Insulate yourself from the work and
ground.
• Always wear dry insulating gloves.
Only qualified personnel should install, use or
service this equipment.
WHAT’S INCLUDED
1. Coarse thread nozzle
2. Contact Tip
3. Diffuser
4. Coarse thread insulator
5. Gun Tube
6. Insulation Tube - (Part of K466-8)
7. Brass Cable Connector - (Part of K466-8)
8. Set Screw - (Part of K466-8)
9. Brass hose nipple - (Part of K466-8)
10. Connector Cover
11. Molded gas plug fitting
12. Trigger Lead Connector - (Part of K466-8 Shown)
13. Trigger - 9SS21002
WARNING
1
2
3
45
6
7
8
12
9
13
10
11
FIGURE 1

A-5
INSTALLATIONMAGNUM PRO®CURVE HDE 250, 350, 450 & 550
CONNECTOR KIT INSTALLATION TO GUN CABLE
The Magnum Pro curve HDE 250, 350, 450 & 550 guns are
shipped as generic assemblies and must be assembled to a
Magnum Connector Kit before they can be connected to a wire
feeder. See Connector Kit Table on page A-1 for appropriate
connector kit.
K466-1 and K466-8 Installation (for Lincoln Feeders)
a) Remove brass cable connector and insulation tube (see Figure
1) from the kit. Slide the insulation tube onto the connector
from the threaded end and screw it onto the feeder end of the
gun cable. Tighten the connection.
b) Remove the molded gas plug fitting on the side of the feeder
end handle and replace it with the barbed brass fitting
provided in the kit.
c) Attach the round connector of the gun control cable provided
to the trigger connector on the front of the Lincoln feeder.
NOTE: Both the plug and socket are keyed and must be
properly oriented.
d) Place one tubing clamp onto each end of the flexible tubing
provided, approximately 2" (51 mm) in from each end. Slide
one end of the tubing onto the barbed connector on the
feeder end cable handle (step b) and move the clamp down
near the end of the tube to assure a good gas seal.
K466-2 Installation (For Tweco Adapted Feeders)
a) Remove brass cable connector (see Figure 1) from the K466-2
kit and screw it onto the feeder end of the gun cable. Tighten
the connection.
b) Check that the molded gas plug fitting is sealing the gas
fitting hole in the side of the feeder end handle.
K466-3 Installation (For Miller feeders)
a) Remove brass cable connector (see Figure 1) from the K466-3
kit and screw it on to the feeder end of the gun cable.
Tighten the connection.
b) Check that the molded gas plug fitting is sealing the gas
fitting hole in the side of the feeder end handle.
c) Attach the round connector of the gun control cable provided
to the trigger connector on the front of the Miller feeder.
K466-6 and K466-10 Installation (Wirematic and
Lincoln 10 Series Feeders)
a) Remove brass cable connector (see Figure 1) from the
connector kit and screw it onto the feeder end of the gun
cable. Tighten the connection with the wrench provided.
b) Check that the molded gas plug fitting is sealing the gas
fitting hole in the side of the feeder end handle.
c) Attach the gun control cable provided to the trigger connector
on the front of the wire feeder.
K613-1 Installation
a) Remove brass cable connector and insulation tube from the
K613-1 Kit. Slide the insulation tube onto the connector from
threaded end and screw it onto the feeder end of the gun
cable. Tighten the connection.
b) Remove the molded gas plug fitting on the side of the feeder
end handle and replace it with the barbed brass fitting
provided in the kit.
c) Attach the round connector of the gun control cable provided
to the trigger connector on the front of the Lincoln Feeder.
Note: Both the plug and socket are keyed and must be properly
oriented.
d) Place one tubing clamp onto each end of the flexible tubing
provided, approximately 2” (51mm) in from each end. Slide
one end of the tubing onto the barbed connector on the
feeder end cable handle (step b) and move the clamp down
near the end of the tube to assure a good gas seal.
K613-3 Installation
a) Remove brass cable connector from the K613-3 kit and screw
it on to the feeder end of the gun cable. Tighten the
connection.
b) Check that the molded gas plug fitting is sealing the gas
fitting hole in the side of the feeder end handle.
c) Attach the round connector of the gun control cable provided
to the trigger connector on the front of the Miller feeder.
K613-2, K613-7 Installation
a) Remove brass cable connector from the kit and screw it onto
the feeder end of the gun tube, Tighten the connection with
wrench provided.
b) For K613-7, attach the round connector of the gun control
cable provided to the trigger connector on the front of the
Lincoln feeder.
K613-6 Installation
a) Remove brass connector and insulation tube from the kit.Slide
the insulation tube onto the connector from the threaded end
and screw it onto the feeder end of the gun cable.tighten the
connection with the wrench provided.
b) Attach the round connector of the gun control cable provided
to the trigger connector on the front of the Lincoln Feeder.

A-5
INSTALLATIONMAGNUM PRO®CURVE HDE 250, 350, 450 & 550
LINER INSTALLATION AND TRIMMING
INSTRUCTIONS
Installation of (KP42, KP44 and KP45 series liners)
a. Lay the gun and cable straight on a flat surface.
b. Make sure that the set screw in the connector end is backed
out so as not to damage liner or liner bushing. Note: Magnum
Pro diffusers don’t have set screws. Remove and save the
gas nozzle, nozzle.insulator, and gas diffuser from the end of
the gun tube assembly.
c. Insert a new untrimmed liner into the connector end of the
cable. Be sure the liner bushing is stenciled appropriately for
the wire size being used.
d. Be sure the cable is straight and then and insert a new
untrimmed liner into the connector end of the cable.
e. Back out the set screw in the connector end and tighten
manually.
f. Trim the liner 0.75 in from the top of the gun tube.
Remove any burrs from the end of the liner.
If needed replace the insulator and gas diffuser and place them on
the end of the gun tube and tighten.
Replace the gas nozzle.
This screw should only be gently tightened. Overtightening
will split or collapse the liner and cause poor wire feeding.
ROTATING THE GUN TUBE
The gun tube can be rotated to any position desired by the
operator. Loosen the front insert molded guntube piece, rotate the
gun tube to the desired position and retighten the nut with hands.
CONTACT TIP AND GAS NOZZLE INSTALLATION
a. Choose the correct size contact tip for the electrode being
used (wire size is stenciled on the side of the contact tip) and
screw it snugly into the gas diffuser.
b. Be sure the nozzle insulator is fully screwed onto the gun tube
and does not block the gas holes in the diffuser.
c. Slip the appropriate gas nozzle onto the nozzle insulator.
Adjustable gas nozzles are available with a .62” (15.9 mm) or
.50” (12.7 mm) I.D., and in both standard (flush) and
recessed design. The proper nozzle should be selected based
on the welding application. Different length fixed nozzles are
also available to allow either spray or short-circuiting transfer
welding.
Choose the gas nozzle as appropriate for the GMAW process
to be used. Typically, the contact tip end should be flush to
.12” (3.1 mm) extended for the short-circuiting transfer
process and .12” (3.1 mm) recessed for spray transfer. For
the Outershield (FCAW) process, 1/8” (3 mm) recess is
recommended
CONNECTION TO FEEDER
Connection to Lincoln Feeders
Gun cable assemblies which were assembled with a K466-1 or -8
Connection Kit will connect easily to any Lincoln LN-7, LN-8, LN-
9, SP-200 or LN-25 feeder.
a. Check that the drive roll(s) and feeder guide tubes are
appropriate for the electrode size being used.
b. Fully push the brass connector end of the gun cable into the
conductor block on the outgoing side of the feeder wire drive.
Secure the cable using the hand screw or set screw in the
conductor block.
c. Insert the control cable plug from the feeder trigger circuit
into the mating socket on the feeder end cable handle (See
K466-1 Installation Section.
d. Slide the free end of the flexible hose onto the barbed gas
fitting on the front of the Lincoln feeder (See K466-1 or -8
Installation Section.) Move the corresponding tubing clamp
down near the end of the tube to assure a good gas seal.
Connection to Tweco Adapted Feeders
Gun cable assemblies which were assembled with a K466-2
Connection Kit will connect easily to any properly adapted feeder.
a. Check that the adapter and feeder outgoing guide, as well as
the drive roll, are appropriate for the electrode size being
used.
b. Fully push the brass connector end of the gun cable into the
brass adapter on the outgoing side of the feeder wire drive.
Secure the cable using the hand screw or set screw in the
adapter.
c. Insert the control cable plug from the feeder trigger circuit
into the mating socket on the gun cable connector handle .
CAUTION

A-6
INSTALLATIONMAGNUM PRO®CURVE HDE 250, 350, 450 & 550
Connection to Miller Feeders
Gun and cable assemblies which were assembled with a K466-3
connection kit will connect easily to a variety of popular Miller wire
feeders.
a. Check that the gun liner, connector cap liner, driverolls and
guide tubes are appropriate for the electrode size being used.
b. Fully push the brass connector end of the gun and cable into
the connector receptacle on the outgoing side of the feeder
wire drive. Tighten the hand screw to clamp down on the
connector.
c. Insert the control cable plug from the feeder trigger circuit
into the mating socket on the gun cable connector hand
Connection To Power MIG®Series, Power Wave®
Gun cable assemblies which were assembled with a K466-6,
Connection Kit will connect easily to a feeder.
a. Check that the adapter and feeder outgoing guide, as well as
the drive roll, are appropriate for the electrode size being
used.
b. Fully push the brass connector end of the gun cable into the
outgoing side of the feeder wire drive. Secure the cable using
the hand screw on the wire feeder.
c. Insert the control cable plug from the feeder trigger circuit
into the mating socket on the gun cable connector handle.
Connection To Lincoln 10 Series Feeders
Gun cable assemblies which were assembled with a K466-10
Connection Kit will connect easily to a 10 Series feeder.
a. Check that the K1500-2 gun adapter is in place on the wire
feeder. Check that the feeder guide tubes, as well as the
drive roll(s), are appropriate for the electrode size being used.
b. Fully push the brass connector end of the gun cable into the
gun adapter on the outgoing side of the feeder wire drive and
secure the cable using the hand screw.
c. Insert the control cable plug from the feeder trigger circuit
into the mating socket on the gun cable connector handle.

B-1
OPERATION
MAGNUM PRO®CURVE HDE 250, 350, 450 & 550
OPERATION
Do not attempt to use this equipment until you
have thoroughly read all operating and mainte-
nance manuals supplied with your machine. They
include important safety precautions, detailed
engine starting, operating and maintenance
instructions and parts lists.
ELECTRIC SHOCK can kill.
• Do not touch electrically live parts such
as output terminals or internal wiring.
• Insulate yourself from the work and
ground.
• Always wear dry insulating gloves.
FUMES AND GASES can be dan-
gerous.
• Keep your head out of fumes.
• Use ventilation or exhaust to remove
fumes from breathing zone.
WELDING SPARKS can cause fire
or explosion.
• Keep flammable material away.
ARC RAYS can burn.
• Wear eye, ear and body protection.
Only qualified personnel should operate this
equipment.
ELECTRODES AND EQUIPMENT
The MAGNUM®PRO CURVE HDE 250-350-450 & 550 guns and
cables have been designed for use with Lincoln L-50 and L-56,
solid steel wire, Lincoln Outershield cored electrodes for the gas-
shielded FCAW process. Refer to the appropriate Lincoln Process
and Procedure Guidelines for the electrode used for information on
recommended electrical and visible stickouts.
MAKING A WELD
WHEN USING AN OPEN ARC PROCESS, IT IS NECESSARY
TO USE CORRECT EYE, HEAD, AND BODY PROTECTION.
a) Check that the welding power source is on and that the
shielding gas supply is set for the proper flow rate.
b) Position electrode over joint. End of the electrode should be
slightly off the work.
c) Lower welding helmet, close gun trigger, and begin welding.
Hold the gun so the contact tip to work distance gives the
correct electrical stickout as required for the procedure being
used.
d) To stop welding, release the gun trigger and then pull the gun
away from the work after the arc goes out.
e) If the optional interlocking trigger is installed, the trigger
operates as follows:
- Pull the trigger in to engage the feeder.
- With the trigger pulled in all the way, the trigger can be slid
forward into the interlock position.
- To release interlock, squeeze trigger and pull back.
AVOIDING WIRE FEEDING PROBLEMS
Wire feeding problems can be avoided by observing the following
gun handling procedures:
a) Do not kink or pull cable around sharp corners.
b) Keep the electrode cable as straight as possible when welding
or loading electrode through cable.
c) Avoid wrapping excess cable around handle or front of wire
feeder especially on 25 foot (7.5 m) length guns.
d) Do not allow dolly wheels or trucks to run over cables.
e) Keep cable clean by following maintenance instructions.
f) Use only clean, rust-free electrode. The Lincoln electrodes
have proper surface lubrication.
g) Replace contact tip when the arc starts to become unstable or
the contact tip end is fused or deformed.
WARNING
WARNING

C-1
ACCESSORIES
MAGNUM® PRO CURVE 250 & 350 GUNS
MAGNUM PRO®CURVE HDE 250, 350, 450 & 550
CONTACT TIP 350 A
Wire Diameter In
(mm)
Standard Standard Tapered Tip Tapered Tip
Pkg. Qty. -10 Pkg. Qty. -100 Pkg. Qty. -10 Pkg. Qty. -100
0.025 (0.6) KP2744-025 KP2744-025-B100 KP2744-025T KP2744-025T-B100
0.030 (0.8) KP2744-030 KP2744-030-B100 KP2744-030T KP2744-030T-B100
0.035 (0.9) KP2744-035 KP2744-035-B100 KP2744-035T KP2744-035T-B100
0.040 (1.0) KP2744-040 KP2744-040-B100 KP2744-040T KP2744-040T-B100
0.045 (1.2) KP2744-045 KP2744-045-B100 KP2744-045T KP2744-045T-B100
0.052 (1.3) KP2744-052 KP2744-052-B100 KP2744-052T KP2744-052T-B100
1/16 (1.6) KP2744-116 KP2744-116-B100 KP2744-116T KP2744-116T-B100
5/64 (2.0) KP2744-564 KP2744-564-B100 KP2744-564T KP2744-564T-B100
GAS DIFFUSER 350 A
Pkg. Qty Thread-on Standard duty Thread-on Extended Reach Slip-On
1 KP2746-1 KP3360-1 KP2746-2
25 KP2746-1-B25 KP3360-1 KP2746-2
GUN TUBE INSULATOR 350 A
Pkg. Qty Part Number
1 KP2746-1
25 KP2746-1-B25
GAS NOZZLE 350 A
Gas Nozzle Diameter In. (mm)
Nozzle Pkg. Qty. Standard 0.375
(9.5) Standard 0.5 (12.7) Extended Reach 0.5 (12.7) Bottleneck 0.5 (12.7) Standard 0.625 (15.9)
Thread-On
1/8 (3.2) Recess 1 KP2742-1-38R KP2742-1-50R KP3359-1-50R KP3160-1-50R KP2742-1-62R
25 KP2742-1-38R-B25 KP2742-1-50R-B25 KP3359-1-50R-B25 KP3160-1-50R-B25 KP2742-1-62R-B25
Flush 1 KP2742-1-38F KP2742-1-50F --- KP3160-1-50F KP2742-1-62F
25 KP2742-1-38F-B25 KP2742-1-50F-B25 --- KP3160-1-50F-B25 KP2742-1-62F-B25
1/8 (3.2)
Stickout
1 KP2742-1-38S KP2742-1-50S --- KP3160-1-50S KP2742-1-62S
25 KP2742-1-38S-B25 KP2742-1-50S-B25 --- KP3160-1-50S-B25 KP2742-1-62S-B25
Slip-On
1/8 (3.2) Recess 1 --- KP2742-2-50R --- --- KP2742-2-62R
25 --- KP2742-2-50R-B25 --- --- KP2742-2-62R-B25
Flush 1 --- KP2742-2-50F --- --- KP2742-2-62F
25 --- KP2742-2-50F-B25 --- --- KP2742-2-62F-B25
1/8 (3.2)
Stickout
1 --- KP2742-2-50S --- --- KP2742-2-62S
25 --- KP2742-2-50S-B25 --- --- KP2742-2-62S-B25

C-2
ACCESSORIES
MAGNUM
®
PRO CURVE 450 & 550 GUNS
MAGNUM PRO®CURVE HDE 250, 350, 450 & 550
CONTACT TIP 550 A
Wire Diameter
In (mm)
Standard Standard Extended Life Extended Life Magnum PRO Tapered Magnum PRO Tapered
Pkg. Qty. -10 Pkg. Qty. -100 Pkg. Qty. -10 Pkg. Qty. -100 Pkg. Qty. -10 Pkg. Qty. -100
0.035 (0.9) KP2745-035 KP2745-035-B100 KP2745-035R KP2745-035R-B100 KP2745-035T KP2745-035T-B100
0.040 (1.0) KP2745-040 KP2745-040-B100 NA NA KP2745-040T KP2745-040T-B100
0.045 (1.2) KP2745-045 KP2745-045-B100 KP2745-045R KP2745-045R-B100 KP2745-045T KP2745-045T-B100
0.052 (1.3) KP2745-052 KP2745-052-B100 KP2745-052R KP2745-052R-B100 KP2745-052T KP2745-052T-B100
1/16 (1.6) KP2745-116 KP2745-116-B100 KP2745-116R KP2745-116R-B100 KP2745-116T KP2745-116T-B100
0.068-0.072
(1.7-1.8)
KP2745-072 KP2745-072-B100 KP2745-072R KP2745-072R-B100 --- ---
5/64 (2.0) KP2745-564 KP2745-564-B100 KP2745-564R KP2745-564R-B100 --- ---
3/32 (2.4) KP2745-332 KP2745-332-B100 KP2745-332R KP2745-332R-B100 --- ---
7/64 (2.8) KP2745-764 KP2745-764-B100 KP2745-764R KP2745-764R-B100 --- ---
1/8 (3.2) KP2745-18 KP2745-18-B100 NA NA --- ---
GAS DIFFUSER 550 A
Pkg. Qty Thread-on
Standard duty Thread-on 1/4 In Recess Slip-On
1 KP2747-1 KP3155-1 KP2747-2
25 KP2747-1-B25 KP3155-1-B25 KP2747-2-B25
GUN TUBE INSULATOR 550 A
Pkg.
Qty Part Number
1 KP2773-1
25 KP2773-1-B25
GAS NOZZLE 550 A
Nozzle Pkg. Qty. Standard 0.625
(15.9)
Bottleneck 0.625
(15.9) Standard 0.750 (19)
Gas Nozzle Diameter
In. (mm)
Magnum Pro Nozzle,
550A 0.375 (9.5)
Gas Nozzle Diameter
In. (mm)
Magnum Pro Nozzle,
550A 0.500 (12.7)
Thread-On
1/8 (3.2) Recess 1 KP2743-1-62R KP3161-1-62R KP2743-1-75R KP2743-1-38R KP2743-1-50R
25 KP2743-1-62R-B25 KP3161-1-62R-B25 KP2743-1-75R-B25 KP2743-1-38R-B25 KP2743-1-50R-B25
Flush 1 KP2743-1-62F KP3161-1-62F KP2743-1-75F KP2743-1-38F KP2743-1-50F
25 KP2743-1-62F-B25 KP3161-1-62F-B25 KP2743-1-75F-B25 KP2743-1-38F-B25 KP2743-1-50F-B25
1/8 (3.2) Stickout 1 KP2743-1-62S KP3161-1-62S KP2743-1-75S KP2743-1-38S KP2743-1-50S
25 KP2743-1-62S-B25 KP3161-1-62S-B25 KP2743-1-75S-B25 KP2743-1-38S-B25 KP2743-1-50S-B25
Slip-On
1/8 (3.2) Recess 1 KP2743-2-62R --- KP2743-2-75R --- ---
25 KP2743-2-62R-B25 --- KP2743-2-75R-B25 --- ---
Flush 1 KP2743-2-62F --- KP2743-2-75F --- ---
25 KP2743-2-62F-B25 --- KP2743-2-75F-B25 --- ---
1/8 (3.2) Stickout 1 KP2743-2-62S --- KP2743-2-75S --- ---
25 KP2743-2-62S-B25 --- KP2743-2-75S-B25 --- ---
Nozzle
Magnum PRO Heavy
Duty Nozzle Front
End 0.625 (15.8)
Magnum PRO Heavy
Duty Nozzle Front
End 0.750 (19)
Pkg. Qty. Magnum PRO Heavy
Duty Nozzle Body
Thread-On
Flush KP3583-1-62F KP3583-1-75F 1
KP3582-1
KP3582-1-B25 (25
pc)
KP3583-1-62F-B25 KP3583-1-75F-B25 25
1/8 (3.2) Recess KP3583-1-62R KP3583-1-75R 1
KP3583-1-62R-B25 KP3583-1-75R-B25 25
1/8 (3.2) Stickout KP3583-1-62S KP3583-1-75S 1
KP3583-1-62S-B25 KP3583-1-75S-B25 25
GUN TUBE
GUN TUBE 60° Gun Tube
Magnum®Pro 250 KP4695-1
Magnum®Pro 350 KP4695-2

D-1
MAINTENANCE
MAINTENANCE
REMOVAL, INSTALLATION AND TRIMMING GUN
LINERS
NOTICE: The variation in cable lengths prevents the interchange-
ability of liners. Once a liner has been cut for a particular gun, it
should not be installed in another gun, unless it can meet the liner
cut off length requirement. Liners are shipped with the jacket of
the liner extended the proper amount.
a. Remove the gas nozzle and nozzle insulator. Loosen the set
screw located in the side of the diffuser with 5/64" (2.0 mm)
Allen wrench (provided with the gun or connector kit).
b. Remove the gas diffuser from gun.
c. Lay gun and cable out straight on a flat surface. For all K466
except K466-3 and K466-4 Connections:
Loosen set screw located in the brass cable connector at the
wire feeder end of the cable using the same 5/64" (2.0 mm)
Allen wrench. Pull liner out of cable.
<OR>
For K466-3 CONNECTIONS:
Remove the connector cap with the wrench provided. Pull
liner out of cable. If the liner is going to be replaced with a
different size liner, loosen set screw on the connector cap
and remove piece of liner material.
d. For installation and trimming instructions for liners see “LINER
INSTALLATION” in INSTALLATION section.
GUN TUBES AND NOZZLES
a) Replace worn contact tips as required.
b) Remove spatter from inside of gas nozzle and from tip after
each 10 minutes of arc time or as required.
c) Unscrew the guntube using the gooseneck nut.
Pull gun tube out from gun handle. To reinstall, insert the gun
tube, push in as far as possible, and re-tighten the gooseneck
nut.
GUN CABLES
Cable Cleaning
Clean cable liner after using approximately 300 (136 kg) pounds of
electrode.
Remove the cable from the wire feeder and lay it out straight on
the floor. Remove the contact tip from the gun. Using an air hose
and only partial pressure, gently blow out the cable liner from the
gas diffuser end.
Flex the cable over its entire length and again blow out the cable.
Repeat this procedure until no further dirt comes out.
Excessive pressure at the start may cause the dirt to form a
plug.
CABLE REPAIR
The MAGNUM®PRO CURVE HDE 250-350-450 & 550 guns feature
the use of repairable cable connectors. If the cable ever gets
severely damaged. it may be cut shorter and repaired by the user.
Repair cables as follows:
Gun Tube End Repair
(Requires 2 S19492-2 Terminals)
a. Remove the cable liner per Removal, Installation and
Trimming Instructions.
b. Remove the gun tube per Gun Tubes and Nozzles Section.
c. Remove three #6 screws from the gun handle, separate the
two halves, and remove the cable from the handle along with
the trigger assembly.
d. Remove gun tube connector from cable by unscrewing
connector nut from gun tube connector. If the cable inner
tube is difficult to remove from the connector assembly,
carefully slit it lengthwise with a knife up to the brass
connector.
e. Uncouple the strain relief by pushing its outer housing toward
the middle of the cable. Move the strain relief and the cable
boot toward the middle of the cable, past the damaged
section.
f. Cut off the damaged section of cable and strip off the outer
jacket as shown in Figure 2. Be careful not to cut the
insulation on the control wires while strip- ping jacket. Strip
the red and white control leads 1/4 inch (6.4 mm) from the
end and crimp a new S19492-2 terminal to each lead.
NOTE: The cable contains control leads. Any two control leads can
be used, provided the two colors used are the same at both
ends. The extra leads are a spare that can be used if one of
the other leads breaks.
g. Check that the cable boot and both halves of the strain relief
are on the cable. Slip the connector nut over the copper
strands with the thread end out. Orient gun tube connector so
machined flat is on the same side of the cable as the red and
white control leads.
Assemble gun tube connector to cable by forcing the steel
tube of the connector into the inside diameter of the cable
inner tube until the copper strands are butted against the gun
tube connector shoulder. Keeping the copper strands against
the shoulder, pull the connector nut over the copper strands,
engage the gun tube connector threads, and tight- en in
place. Refer to Figure 3.
NOTE: For best results, insert a .219”/.240” (5.6/6.1 mm)
diameter rod through the connector and into core of cable
approximately 5.00 (127 mm) when pushing the connector
tube into the cable core tube. To tighten, hold the connector
in place while turning the nut, then remove the rod from the
core. This procedure ensures the inner core does not kink
while assembling or tightening.
h. Pull the cut-off lead terminals off the trigger assembly and
connect the replacement control lead terminals.
CAUTION
MAGNUM PRO®CURVE HDE 250, 350, 450 & 550

D-2
MAINTENANCE
i Position the cable boot and strain relief on the cable so it fits
in cable handle cavity and lock the strain relief in place by
pushing the two halves together.
j. Assemble cable in left side of gun handle. Assemble trigger
into the proper handle cavity. Assemble right side of gun
handle and tighten the three screws that hold the handle
together. Refer to Figure 4.
k. Install gun tube per Gun Tubes and Nozzles Section.
l. Install and trim liner per Liner Installation Section.
MAGNUM PRO®CURVE HDE 250, 350, 450 & 550
FIGURE 3
FIGURE 2 – 250 & 350 AMPS
FIGURE 2 - 450
FIGURE 2 - 550

D-3
MAINTENANCE
MAGNUM PRO®CURVE HDE 250, 350, 450 & 550
Wire Feeder End Repair
(REQUIRES 2 #S19492-1 TERMINALS)
a. Remove the cable liner per Removal, Installation, and
Trimming Instruction.
b. Remove the feeder end connector, molded gas plug (or
barbed fitting), cable handle nut, plastic tailpiece and
connector cover (see Figure 5).
NOTE: In order to remove the cable handle nut, the tail of the
connector cover must be depressed and the cable handle nut
rotated 1/4 turn counterclock- wise as viewed from the
feeder end.
c. Remove incoming connector from cable by unscrewing
connector nut from incoming connector. If the cable inner
tube is difficult to remove from the connector assembly,
carefully slit it lengthwise with a knife up to the brass
connector.
d. Move the cable boot and cable handle toward the middle of
the cable past the damaged section.
e. Cut off the damaged section of cable and strip off the outer
jacket as shown in Figure 2. Be careful not to cut the
insulation on the control wires while strip- ping jacket. Strip
the red and white control leads 1/4 inch (6.4 mm) from the
end and crimp a new S19492-1 terminal to each lead.
NOTE: The cable contains three control leads. Any two control
leads can be used, provided the two col- ors used are the
same at both ends. The extra lead is a spare that can be used
if one of the other leads breaks.
f. Check that the cable boot and cable handle are on the cable.
Slip the connector nut over the copper strands with the
threaded end out. Assemble incoming connector to cable by
forcing the steel tube of the connector into the inside
diameter of the cable inner tube until the copper strands are
butted against the incoming connector shoulder. Keeping the
copper strands against the shoulder, pull the connector nut
over the copper strands, engage the incoming connector
threads, and tighten in place. Refer to Figure 3.
NOTE: For best results, insert a .219"/.240" (5.6/6.1 mm)
diameter rod through the connector and into core of cable
approximately 5.00” (127 mm) when pushing the connector
tube into the cable core tube. To tighten, hold the connector
in place while turning the nut. then remove the rod from the
core. This procedure ensures the inner core does not kink
while assembling or tightening.
Position the plastic strain relief such that the tapered end is
4.68 (119 mm) from the incoming connector (see Figure 5).
Lock into place with steel housing. Plastic strain relief may
overhang cable jacket a maximum of .43" (11 mm).
g. Position cable boot and cable handle on cable and assemble
replacement control wire terminals in place on the cable
handle. Insert connector cover in place. Install tailpiece and
fasten to cable handle with cable handle nut. Refer to Figure
5.
h. Replace the molded gas plug (or barbed fitting) and feeder
end connector.
i. Install and trim liner per Liner Installation Section.
Gun Tube
Gooseneck Nut Gun Housing
Trigger Assembly
Cable Assembly
FIGURE 4