Chicago Electric 6271 User manual

DUAL MIG WELDER 151DUAL MIG WELDER 151
DUAL MIG WELDER 151DUAL MIG WELDER 151
DUAL MIG WELDER 151
ASSEMBLY AND OPERATING INSTRUCTIONS
3491 Mission Oaks Blvd., Camarillo, CA 93011
Visit our Web site at http://www.harborfreight.com
Copyright © 2007 by Harbor Freight Tools®. All rights reserved. No portion of
this manual or any artwork contained herein may be reproduced in any shape or
form without the express written consent of Harbor Freight Tools.
For technical questions and replacement parts, please call 1-800-444-3353
55250
®

Page 2SKU 55250 For technical questions, please call 1-800-444-3353.
Specifications
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Save This Manual
You will need the manual for the safety warnings and precautions, assembly instructions,
operating and maintenance procedures, parts list and diagram. Keep your invoice with this
manual. Write the invoice number on the inside of the front cover. Keep the manual and
invoice in a safe and dry place for future reference.
Safety Warnings and Precautions
WARNING: When using tool, basic safety precautions should always be followed to
reduce the risk of personal injury and damage to equipment.
Read all instructions before using this tool!
1. Keep work area clean. Cluttered areas invite injuries.
2. Observe work area conditions. Do not use machines or power tools in damp or wet
locations. Don’t expose to rain. Keep work area well lighted. Do not use electrically
powered tools in the presence of flammable gases or liquids.
3. Keep children away. Children must never be allowed in the work area. Do not let them
handle machines, tools, or extension cords.

Page 3SKU 55250 For technical questions, please call 1-800-444-3353.
4. Store idle equipment. When not in use, tools must be stored in a dry location to inhibit
rust. Always lock up tools and keep out of reach of children.
5. Do not force tool. It will do the job better and more safely at the rate for which it was
intended. Do not use inappropriate attachments in an attempt to exceed the tool capacity.
6. Use the right tool for the job. Do not attempt to force a small tool or attachment to do
the work of a larger industrial tool. There are certain applications for which this tool was
designed. Do not modify this tool and do not use this tool for a purpose for which it was
not intended.
7. Dress properly. Do not wear loose clothing or jewelry as they can be caught in moving
parts. Protective, electrically nonconductive clothes and nonskid footwear are
recommended when working. Wear restrictive hair covering to contain long hair.
8. Use protective gear. Always wear ANSI approved, arc shaded, impact safety full face
shield when arc welding.Wear an ANSI approved dust mask or respirator when working
around metal, chemical dusts, fumes and mists. Always wear ANSI approved welding
gear: leather gloves, leather apron, and shoes.
9. Do not overreach. Keep proper footing and balance at all times. Do not reach over or
across running machines.
10. Maintain tools with care. Keep tools sharp and clean for better and safer performance.
Follow instructions for lubricating and changing accessories.Inspect tool cords periodically
and, if damaged, have them repaired by an authorized technician. The handles must be
kept clean, dry, and free from oil and grease at all times.
11. Disconnect power. Unplug tool when not in use.
12. Remove adjusting keys and wrenches. Check that keys and adjusting wrenches are
removed from the tool or machine work surface before plugging it in.
13. Avoid unintentional starting. Be sure the switch is in the Off position when not in use
and before plugging in. Do not carry any tool with your finger on the trigger, whether it is
plugged in or not.
14. Stay alert. Watch what you are doing, use common sense. Do not operate any tool
when you are tired.
15. Check for damaged parts. Before using any tool, any part that appears damaged
should be carefully checked to determine that it will operate properly and perform its
intended function. Check for alignment and binding of moving parts; any broken parts or
mounting fixtures; and any other condition that may affect proper operation. Any part
that is damaged should be properly repaired or replaced by a qualified technician. Do
not use the tool if any switch does not turn On and Off properly.
16. Guard against electric shock. Prevent body contact with grounded surfaces such as
pipes, radiators, ranges, and refrigerator enclosures.
17. Replacement parts and accessories. When servicing, use only identical replacement
parts. Use of any other parts will void the warranty. Only use accessories intended for
use with this tool. Approved accessories are available from Harbor Freight Tools.
18. Do not operate tool if under the influence of alcohol or drugs. Read warning labels
on prescriptions to determine if your judgment or reflexes are impaired while taking
drugs. If there is any doubt, do not operate the tool.

Page 4SKU 55250 For technical questions, please call 1-800-444-3353.
Arc Welding Safety Warnings and Precautions
1. Avoid electrical shock. Do not permit electrically live parts, cables, or electrodes to
contact skin, clothing, or gloves. Protective clothing should be free of holes, dry, and
ANSI approved.
This unit draws enough current to cause serious injury or death. Before turning the
welder on, check the electrode holder to be sure that there are no protruding screw
heads, and that all insulation is secure. Do not weld unless you are insulated from ground
and the work piece.
2. Avoid breathing fumes or gases. They can cause serious health problems. Use an
active ventilation system directly above the welding area. Keep your head out of the
fumes.
3. Avoid eye and body damage. Arc rays and infrared radiation can injure eyes and burn
skin. Wear ANSI approved eye and body protection. Do not allow viewing by visitors
without proper eye and body protection. Use a Face Shield with arc shaded filter plate.
4. Know proper arc welding practices. Read and understand this instruction manual,
and well as your employer’s safety practices for arc welding.
5. Avoid fire and explosion. Remove flammable and explosive material from at least 35
feet from the welding arc to prevent welding sparks or molten metal from starting a fire.
Keep a type ABC fire extinguisher within easy reach. Thoroughly clean the object being
welded of any paint, grease, or other foreign material.
6. This product, when used for welding and similar applications, produces chemicals known
to the State of California to cause cancer and birth defects (or other reproductive harm).
(California Health & Safety Code § 25249.5,
et seq. )
19. Maintenance. For your safety, service and maintenance should be performed regularly
by a qualified technician.
20. Use proper size and type extension cord. If an extension cord is required, it must be
of the proper size and type to supply the correct current to the tool without heating up.
Otherwise, the extension cord could melt and catch fire, or cause electrical damage to
the tool. This tool requires use of an 220 VAC extension cord of 20 amps minimum
capability (up to 30 feet), with wire size rated at 10 AWG.Longer extension cords require
larger size wire. If you are using the tool outdoors, use an extension cord rated for
outdoor use (signified by “WA” on the jacket).
21. Pacemaker safety warning. People with pacemakers should consult with their
physician(s) before using this product; operation of equipment in close proximity to a
heart pacemaker could cause interference or failure of the pacemaker.
Note: Performance of this tool may vary depending on variations in local line voltage. Exten-
sion cord usage may also affect tool performance.
Warning:The warnings, cautions, and instructions discussed in this instruction manual
cannot cover all possible conditions and situations that may occur. It must be under-
stood by the operator that common sense and caution are factors which cannot be
built into this product, but must be supplied by the operator.

Page 5SKU 55250 For technical questions, please call 1-800-444-3353.
Unpacking
When unpacking, check to make sure the following parts are included.
If any parts are missing or broken, please call Harbor Freight Tools at the number on the
cover of this manual as soon as possible.
Brush Hammer
Handheld Shaded
Face Shield
Wheels (29)
Axle (30)
Welding Torch (16)
Grounding Cable
with Clamp (15)
Line Cord (14)
Handle (4)
Wire Spool not shown
7. Connect only to a code approved power source. Connect only to a grounding power
source conforming to the National Electrical Code and Local Codes.
8. Wear proper clothing when welding. Use flameproof, welding-type gloves. Wear
cuffless pants and pocketless shirt. Both must be free of oil and grease. Wear high-
topped, safety shoes with rubber soles.

Page 6SKU 55250 For technical questions, please call 1-800-444-3353.
Assembly
MIGWelder Unit
1. Assemble the Axle (30) and Wheels (29) as illustrated in the Wheel Assembly Drawing
at the end of this manual.
2. Place the second wheel over the end of the Axle and secure in place with the Axle
locking clip.
3. Insert the Handle (4) into the Handle Sockets (3) and mount the Handle Sockets to
the Side Panel B (1) top using supplied hardware.
Note: The Handle (4) configuration may differ slightly than what is shown in this manual.
4. Lift Side Panel B (1) all the way to expose the wire spool and Wire Feed Mechanism
(11).
5. Remove the Nut from the Wire Spool Axle (10). Place the Wire Spool over the Axle
with the wire exiting the spool over the top. Refer to photos above. Replace the Spool
Axle Nut.
6. Open the Wire Feed Mechanism (11) as shown in the photo (top-right).
7. Feed and guide the spool wire into the Wire Feed Mechanism, past the feed wheels
(C), and into the Welding Torch / Cable (16).
It will help if the Welding Torch / Cable (16) is straightened out as much as possible.
Push in until the wire comes out the Welding Torch head. If it cannot be fed manually
all the way out, it can be fed automatically when the welding unit is powered up.
8. Close the Feed Mechanism (11) over the wire, and adjust the feed tension (D) if
necessary.
9. Check that +/– cables to connection Knobs (34) are correct. See photo (top-left).
When using non-flux wire and protective gas, connect wire cables as shown in photo.
For flux cored wire, no gas is required. Reverse cable connections.
10. Close the Side Panel B (1).
Wire Feed Mechanism (11)
Wire Spool
Wire Spool Axle (10)
Side Panel B (1)
(C)
(D)
(34)
–
+

Page 7SKU 55250 For technical questions, please call 1-800-444-3353.
Operation
Controls and Indicators
Welding
Caution: Before arc welding, read and understand all safety precautions and warnings
listed on pages 2 through 5.
1. If using non-flux core wire, connect and secure the Argon/CO2
gas hose to the rear of the MIG Welder. (If using flux core wire,
protective gas is not required.)
2. Attach the Ground Cable with Clamp (15) as close as possible
to the metal object to be welded, or to the metal work bench
where the object is mounted and electrically connected.
3. Set the desired welding current (30~120 amps) for the type of metal being welded
using the Min/Max Switch and 1/2 Power Level Switch.
Refer to the power setting table on the next page. Thinner metals use lower current.
Heavier metals use higher current.
4. Verify that the On/Off Switch is in the OFF position, then plug the MIG Welder Line
Cord into a dedicated, 220 VAC, 20 amp line with delayed action type circuit breaker
11. A licensed electrician must connect a 220 V~ plug (not supplied) to the line cord.
Green wire = ground; Black wire = hot (110 V~, Leg 1);White wire = hot (110 V~, Leg 2)
Handheld Shaded Face Shield
Assemble the Handheld Shaded Face Shield as illustrated in its Assembly Drawing at the
end of this manual.
On / Off Switch
Min / Max Switch
1 / 2 Power Level Switch
Overload-shutdown
Indicator Lamp
Wire Feed Speed Control
Line Cord
Ground Cable with Clamp (15) Welding Torch Cable (16)

Page 8SKU 55250 For technical questions, please call 1-800-444-3353.
or fuses. If an extension cord is used, it must have the following wire size: up to 30 feet,
use 10 AWG size wire; 30 to 50 feet, 8 AWG wire; Over 50 feet, 6 AWG wire.
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5. While holding the Welding Torch handle, with the electrode wire clearly out of the way
of any grounded objects, turn the On/Off Switch to the ON position.
6. Momentarily press the Welding Torch trigger switch to test the wire feed speed.
Adjust the speed by turning the Wire Feed Speed Control knob.
7. Orient yourself on the area to be welded, then hold the Arc Shaded Face Shield over
your eyes.
Warning: Never look at the ignited arc without ANSI approved, arc shaded, eye protec-
tion in a full face shield. Permanent eye damage or blindness can occur. Skin burns can
occur. Never breath arc fumes.
8. Press (and hold) the Torch Trigger Switch and stroke the area to be welded with the
electrode wire to ignite the arc.
Never tap the electrode wire into the welding surface to
ignite the arc. This damages its external coating on the
electrode which prevents oxygen in the air from coming
into contact with the molten metal, causing it to oxidize.
9. Once the arc is ignited, tilt the electrode wire forward at an
angle of about 35°. Refer to the illustration at right.
The wire feeds automatically at a speed dependent on the
Min. or Max. current setting.The wire speed can also be
adjusted using the Wire Feed Speed Control.
Note: If too much current is drawn from the MIG Welder, the Thermal Overload protector will
activate, the red Overload indicator will light, and the Arc Welder will turn off until it cools down.
If this happens, turn the On/Off Switch to the OFF position and wait about 3 ~ 5 minutes.
10. When the weld is complete, lift the Welding Torch handle electrode wire clearly away
from any grounded object, remove your Face Shield, and turn the On/Off Switch to the
OFF position.
11. Unplug the power Line Cord from the electrical outlet.

Page 9SKU 55250 For technical questions, please call 1-800-444-3353.
Troubleshooting
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Maintenance
Caution: Before performing any maintenance on the MIGWelder, unplug the power Line
Cord from the electrical outlet.
1. Periodically using compressed air, open the top and side panels and blow out all dust
from the interior.

Page 10SKU 55250 For technical questions, please call 1-800-444-3353.
NOTE: Some parts are listed and shown for illustration purposes only and are not available
individually as replacement parts.
PLEASE READ THE FOLLOWING CAREFULLY
THE MANUFACTURER AND/OR DISTRIBUTOR HAS PROVIDED THE PARTS DIAGRAM IN THIS
MANUAL AS A REFERENCE TOOL ONLY. NEITHER THE MANUFACTURER NOR DISTRIBU-
TOR MAKES ANY REPRESENTATION OR WARRANTY OF ANY KIND TO THE BUYER THAT
HE OR SHE IS QUALIFIEDTO MAKE ANY REPAIRS TO THE PRODUCT OR THAT HE OR SHE
IS QUALIFIED TO REPLACE ANY PARTS OF THE PRODUCT. IN FACT, THE MANUFACTURER
AND/OR DISTRIBUTOR EXPRESSLY STATES THAT ALL REPAIRS AND PARTS REPLACE-
MENTS SHOULD BE UNDERTAKEN BY CERTIFIED AND LICENSED TECHNICIANS AND NOT
BY THE BUYER. THE BUYER ASSUMES ALL RISK AND LIABILITY ARISING OUT OF HIS OR
HER REPAIRS TO THE ORIGINAL PRODUCT OR REPLACEMENT PARTS THERETO, OR ARIS-
ING OUT OF HIS OR HER INSTALLATION OF REPLACEMENT PARTS THERETO.
Parts List
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2. Store the unit in a clean and dry location.
3. Periodically clean out the Torch Head.
Replacing the Wire Reel
When the wire on the Feed Reel is used up, you will need to replace it as described on
page 6, step 5 through step 9.

Page 11SKU 55250 For technical questions, please call 1-800-444-3353.
MIG Welder Dual 151 Assembly Drawing

Page 12SKU 55250 For technical questions, please call 1-800-444-3353.
Wire Feed Mechanism Assembly Drawing

Page 13SKU 55250 For technical questions, please call 1-800-444-3353.
MIG Welder Dual 151 Schematic Diagram
Wheel and Axle Assembly Drawing
3

Page 14SKU 55250 For technical questions, please call 1-800-444-3353.
Hand Held Shield Assembly Drawing