Chicago Electric 66042 Installation manual

DC INVERTER
ARC WELDING MACHINE
Model 66042
SET UP AND OPERATING INSTRUCTIONS
Diagrams within this manual may not be drawn proportionally.
Due to continuing improvements, actual product may differ slightly from the product described herein.
Distributed exclusively by Harbor Freight Tools®.
3491 Mission Oaks Blvd., Camarillo, CA 93011
Visit our website at: http://www.harborfreight.com
Read this material before using this product.
Failure to do so can result in serious injury.
SAVE THIS MANUAL.
Copyright©2008 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 or replacement parts, please call 1-800-444-3353.

Page 2SKU 66042 For technical questions, please call 1-800-444-3353.
TABLE OF CONTENTS
IMPORTANT SAFETY INFORMATION............................................................................3
GENERAL SAFETY RULES............................................................................................3
SPECIFIC SAFETY RULES.............................................................................................5
SPECIFICATIONS............................................................................................................8
UNPACKING....................................................................................................................8
PRODUCT FEATURES....................................................................................................8
ASSEMBLY INSTRUCTIONS..........................................................................................9
WORKPIECE & WORK AREA SET UP.........................................................................10
GENERAL OPERATING INSTRUCTIONS....................................................................10
MAINTENANCE & SERVICING.....................................................................................12
TROUBLESHOOTING...................................................................................................13
PLEASE READ THE FOLLOWING...............................................................................13
PARTS LIST & ASSEMBLY DIAGRAM.........................................................................14
ELECTRICAL SCHEMATIC...........................................................................................15
WARRANTY INFORMATION.........................................................................................16

Page 3SKU 66042 For technical questions, please call 1-800-444-3353.
SAVE THIS MANUAL
Keep this manual for the safety warn-
ings and precautions, assembly, operating,
inspection, maintenance and cleaning pro-
cedures. Write the product’s serial number
in the back of the manual (or month and
year of purchase if product has no num-
ber). Keep this manual and the receipt in
a safe and dry place for future reference.
IMPORTANT SAFETY
INFORMATION
In this manual, on the labeling,
and all other information
provided with this product:
This is the safety alert
symbol. It is used to alert
you to potential personal
injury hazards. Obey all
safety messages that
follow this symbol to avoid
possible injury or death.
DANGER indicates
a hazardous
situation which, if not
avoided, will result in death or
serious injury.
WARNING
indicates a
hazardous situation which, if
not avoided, could result in
death or serious injury.
CAUTION, used
with the safety
alert symbol, indicates a
hazardous situation which, if
not avoided, could result in
minor or moderate injury.
NOTICE is used to
address practices
not related to
personal injury.
CAUTION, without
the safety alert
symbol, is used to address
practices not related to
personal injury.
General Safety Rules
WARNING! Read all
instructions.
Failure to follow all instructions
listed below may result in
electric shock, re, and/or
serious injury.
SAVE THESE INSTRUCTIONS
Work area safety1.
Keep work area clean and well lit.a.
Cluttered or dark areas invite acci-
dents.
Do not operate the Welder in ex-b.
plosive atmospheres, such as in
the presence of ammable liquids,
gases or dust. Power tools create
sparks which may ignite the dust or
fumes.
Keep children and bystanders awayc.
while operating the Welder. Distrac-
tions can cause you to lose control.
Electrical safety2.
Avoid body contact with groundeda.
surfaces such as pipes, radiators,
ranges and refrigerators. There is
an increased risk of electric shock if
your body is grounded.
Do not touch exposed electricalb.
parts.
DANGER
WARNING
CAUTION
NOTICE
CAUTION

Page 4SKU 66042 For technical questions, please call 1-800-444-3353.
Do not expose the Welder to rainc.
or wet conditions. Water entering a
power tool will increase the risk of
electric shock.
Do not abuse the Power Cord (21).d.
Never use the Cord for pulling or
unplugging the Welder. Keep the
Cord away from heat, oil, sharp
edges or moving parts. Damaged or
entangled Cords increase the risk of
electric shock.
Personal safety3.
Stay alert, watch what you are do-a.
ing and use common sense when
operating the Welder. Do not use
a power tool while you are tired or
under the inuence of drugs, alcohol
or medication. A moment of inatten-
tion while operating power tools may
result in serious personal injury.
Use safety equipment. Always wear b.
eye protection. Safety equipment
such as ANSI-approved/NIOSH-ap-
proved arc shaded, impact safety full
face shield, dust mask or respirator,
heavy-duty work gloves, non-skid
safety shoes, or hearing protection
used for appropriate conditions will
reduce personal injuries.
Avoid accidental starting. Ensurec.
the Power Switch (18) is in the off-
position before plugging in. Carrying
power tools with your nger on the
Switch or plugging in power tools
that have the Switch on invites ac-
cidents.
Remove any adjusting key or wrenchd.
before turning the Welder on. A
wrench or a key left attached to an
electrically charged part of the power
tool may result in personal injury.
Do not overreach. Keep proper foot-e.
ing and balance at all times. This
enables better control of the Welder
in unexpected situations.
Welder use and care4.
Do not force the Welder. Use thea.
correct power tool for your applica-
tion. The correct power tool will do
the job better and safer at the rate
for which it was designed.
Do not use the Welder if the Powerb.
Switch (18) does not turn it on and
off. Any power tool that cannot be
controlled with the Switch is danger-
ous and must be repaired prior to
use.
Disconnect the Power Cord Plugc.
(21) from the power source before
making any adjustments, changing
accessories, or storing power tools.
Such preventive safety measures
reduce the risk of starting the power
tool accidentally.
Store idle power tools out of thed.
reach of children and do not allow
persons unfamiliar with the Welder
or these instructions to operate the
power tool. Power tools are danger-
ous in the hands of untrained users.
Maintain the Welder. Check fore.
misalignment or binding of moving
parts, breakage of parts and any
other condition that may affect the
power tool’s operation. If damaged,
have the power tool repaired before
use. Many accidents are caused by
poorly maintained power tools.
Use the Welder and its accessoriesf.
in accordance with these instructions
and in the manner intended for the
particular type of power tool, taking
into account the working conditions

Page 5SKU 66042 For technical questions, please call 1-800-444-3353.
and the work to be performed. Use
of the Welder for operations different
from those intended could result in a
hazardous situation.
Service5.
Have your Welder serviced by aa.
qualied repair person using only
identical replacement parts. This will
ensure that the safety of the power
tool is maintained.
Specic Safety Rules
Ground this Welder. This Welder1.
requires the attachment and use of a
UL®listed, 230 volt, grounded,
3-prong, electrical Power Cord
Plug (not included). Only a quali-
ed electrician should install the
Power Cord Plug. Never remove the
grounding prong or modify the Plug
in any way. Do not use adapter plugs
with this product.
Maintain labels and nameplates on2.
the Welder. These carry important
safety information. If unreadable or
missing, contact Harbor Freight Tools
for a replacement.
Avoid electrical shock. Do not per-3.
mit electrically live parts, cables, or
electrodes to contact skin, clothing, or
gloves. Wear ANSI-approved protec-
tive clothing. 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 se-
cure. Do not weld unless you are
insulated from the ground and the
work piece.
Avoid eye and body damage. Arc4.
rays and infrared radiation can injure
eyes and burn skin. Wear ANSI ap-
proved eye and body protection. Do
not allow viewing by visitors without
proper eye and body protection. Use
a Face Shield with arc shaded lter
plate.
Move ammable and explosive mate-5.
rial at least 35 feet from the welding
arc to prevent sparks or molten metal
from starting a re. Keep a type ABC
re extinguisher within easy reach.
Thoroughly clean the workpiece of
any paint, grease, or other foreign
material.
Avoid unintentional starting. Prepare6.
to begin work before turning on the
Welder.
Do not leave the Welder unattended7.
when it is plugged into an electrical
outlet. Turn off the tool, and unplug it
from its electrical outlet before leav-
ing.
Use clamps (not included) or other8.
practical ways to secure and support
the work piece to a stable platform.
Holding the work by hand or against
your body is unstable and may lead
to loss of control.
This product is not a toy. Keep it out9.
of reach of children.
Industrial applications must follow10.
OSHA guidelines.
People with pacemakers should11.
consult their physician(s) before use.
Electromagnetic elds in close prox-
imity to heart pacemaker could cause
pacemaker interference or pacemak-
er failure. In addition, people with
pacemakers should:

Page 6SKU 66042 For technical questions, please call 1-800-444-3353.
• Avoid operating alone.
• Do not use with power switch locked
on.
• Properly maintain and inspect to
avoid electrical shock.
• Any power cord must be properly
grounded. Ground Fault Circuit Inter-
rupter (GFCI) should also be imple-
mented – it prevents sustained elec-
trical shock.
WARNING: This product, when used12.
for welding or similar applications,
produces chemicals known to the
State of California to cause cancer
and birth defects (or other reproduc-
tive harm). (California Health & Safe-
ty Code § 25249.5, et seq.)
13. Prevent eye injury and
burns. Wearing ANSI-ap-
proved personal safety
clothing and safety de-
vices reduce the risk for
injury.
Wear ANSI-approved safety impact•
eye goggles underneath welding
eye protection featuring at least a
Number 10 shade lens rating.
Leather leggings, re resistant •
shoes or boots should be worn
when using this product. Do not
wear pants with cuffs, shirts with
open pockets, or any clothing that
can catch and hold molten metal or
sparks.
Keep clothing free of grease, oil,•
solvents, or any ammable sub-
stances. Wear dry, insulating gloves
and protective clothing.
Wear an approved head covering•
to protect the head and neck. Use
aprons, cape, sleeves, shoulder
covers, and bibs designed and ap-
proved for cutting procedures.
When cutting overhead or in con-•
ned spaces, wear ame resistant
ear plugs or ear muffs to keep
sparks out of ears.
14. Prevent accidental res.
Remove any combustible
material from the work
area.
When possible, move the work to a•
location well away from combustible
materials. If relocation is not pos-
sible, protect the combustibles with
a cover made of re resistant mate-
rial.
Remove or make safe all combus-•
tible materials for a radius of 35 feet
(10 meters) around the work area.
Use a re resistant material to cover
or block all open doorways, win-
dows, cracks, and other openings.
Enclose the work area with por-•
table re resistant screens. Protect
combustible walls, ceilings, oors,
etc., from sparks and heat with re
resistant covers.
If working on a metal wall, ceiling,•
etc., prevent ignition of combus-
tibles on the other side by moving
the combustibles to a safe loca-
tion. If relocation of combustibles
is not possible, designate someone
to serve as a re watch, equipped
with a re extinguisher, during the
cutting process and for at least one
half hour after the welding is com-
pleted.
Do not weld on materials having a•
combustible coating or combustible
internal structure, as in walls or ceil-
ings, without an approved method
for eliminating the hazard.

Page 7SKU 66042 For technical questions, please call 1-800-444-3353.
Do not dispose of hot slag in con-•
tainers holding combustible materi-
als. Keep a re extinguisher nearby
and know how to use it.
After welding, make a thorough•
examination for evidence of re. Be
aware that easily-visible smoke or
ame may not be present for some
time after the re has started. Do
not weld in atmospheres contain-
ing dangerously reactive or am-
mable gases, vapors, liquids, and
dust. Provide adequate ventilation
in work areas to prevent accumula-
tion of ammable gases, vapors,
and dust. Do not apply heat to a
container that has held an unknown
substance or a combustible material
whose contents, when heated, can
produce ammable or explosive va-
pors. Clean and purge containers
before applying heat. Vent closed
containers, including castings, be-
fore preheating or welding.
Do not touch live electrical parts.15.
Wear dry, insulating gloves. Do not
touch electrode or conductor tong
with bare hand. Do not wear wet or
damaged gloves.
Protect yourself from electric shock.16.
Do not use outdoors. Insulate your-
self from the workpiece and ground.
Use nonammable, dry insulating
material if possible, or use dry rubber
mats, dry wood or plywood, or other
dry insulating material big enough to
cover your full area of contact with
the work or ground.
Always keep hoses and cables away17.
from the welding spot. Examine all
hoses and cables for cuts, burns, or
worn areas before each use. If any
damaged areas are found, replace
the hoses or cables immediately.
Read and understand all instructions18.
and safety precautions as outlined
in the manufacturer’s manual for the
material you will weld.
Use only the supplied Torch with this19.
Welder. Using components from
other systems may cause severe per-
sonal injury and damage components
within.
Ensure that the unit is placed on a20.
stable location before use. If this unit
falls while plugged in, severe injury,
electric shock, or re may result.
Avoid overexposure to fumes and21.
gases. Always keep your head out
of the fumes. Do not breathe the
fumes. Use enough ventilation or
exhaust, or both, to keep fumes and
gases from your breathing zone and
general area.
Where ventilation is questionable, •
have a qualied technician take
an air sampling to determine the
need for corrective measures. Use
mechanical ventilation to improve
air quality. If engineering controls
are not feasible, use an approved
respirator.
Follow OSHA guidelines for Permis-•
sible Exposure Limits (PEL’s) for
various fumes and gases.
Follow the American Conference•
of Governmental Industrial Hygien-
ists recommendations for Threshold
Limit Values (TLV’s) for fumes and
gases.
Have a recognized specialist in•
Industrial Hygiene or Environmental
Services check the operation and

Page 8SKU 66042 For technical questions, please call 1-800-444-3353.
air quality and make recommenda-
tions for the specic welding situa-
tion.
WARNING
INHALATION HAZARD:
Welding and Plasma Cutting Produce
TOXIC FUMES.
Exposure to welding or cutting
exhaust fumes can increase the risk
of developing certain cancers, such as
cancer of the larynx and lung cancer.
Also, some diseases that may be linked
to exposure to welding or plasma cutting
exhaust fumes are:
• Early onset of Parkinson’s Disease
• Heart disease • Ulcers
• Damage to the reproductive organs
• Inammation of the small intestine or
stomach • Kidney damage
• Respiratory diseases such as
emphysema, bronchitis, or pneumonia
Use natural or forced air ventilation and
wear a respirator approved by NIOSH to
protect against the fumes produced to
reduce the risk of developing the above
illnesses.
The warnings, precautions, and in-22.
structions discussed in this instruction
manual cannot cover all possible con-
ditions and situations that may occur.
It must be understood by the operator
that common sense and caution are
factors which cannot be built into this
product, but must be supplied by the
operator.
SAVE THESE INSTRUCTIONS.
SPECIFICATIONS
Electrical
Requirements
Input Voltage: 230 V~
60 Hz / Single Phase
Input Current: 26.0 Amps
Output Current: 130.0 Amps Max.
Output current
range
Duty Cycle:
100% @ 65.0 Amps
25% @ 130 Amps
Max. Open
Circuit Volt
(2-1/2 Min. ON per 10 minute
cycle
Power Cord
Plug
Required Power Cord Plug:
UL®Listed, Grounded, 3-Prong
(Not Included)
Material
Capacity 11 Gauge Steel Plate
Electrode Size Up to 1/8”
Cooling Method Fan Cooled
Accessories Electrode Holder (Qty. 1)
Ground Clamp (Qty. 1)
UNPACKING
When unpacking, check to make sure the
item is intact and undamaged. If nay parts
are missing or broken, please call Harbor
Freight Tools at the number shown on the
cover of this manual as soon as possible.
PRODUCT FEATURES
Ampere Selector (9):1. To regulate
the welding current.
(See Figure A, next page.)
Negative Terminal (11):2. Connect
the Ground Clamp (23) to this Termi-
nal. (See Figure A.)
Fault Indicator (12):3. Illumination of
the YELLOW Fault Indicator indicates
overheating caused by an excessive-
ly intense duty cycle. In this case,
stop welding and turn the Power
Switch OFF until the Fault Indica-
tor turns off. Then resume welding.
(See Figure A.)

Page 9SKU 66042 For technical questions, please call 1-800-444-3353.
Power Switch (18):4. The GREEN
(ON/OFF) Power Switch must illumi-
nate before welding operations can
be started. (See Figure A.)
Fan (19):5. The Fan must operate
continuously when operating the
Welder to prevent the unit from over-
heating. (See Figure A.)
Power Cord (21):6. Do not abuse the
Power Cord. Never use the Cord
for pulling or unplugging the Welder.
Keep the Cord away from heat, oil,
sharp edges or moving parts.
Positive Terminal (24):7. Connect the
Electrode Holder Cable (22) to this
Terminal. (See Figure A.)
ASSEMBLY INSTRUCTIONS
Read the ENTIRE IMPORTANT
SAFETY INFORMATION section
at the beginning of this manual
including all text under
subheadings therein before set
up or use of this product.
Note: For additional information regarding
the parts listed in the following pages,
refer to the Assembly Diagram near
the end of this manual.
TO PREVENT
SERIOUS INJURY
FROM ACCIDENTAL
OPERATION:
Turn the Power Switch (18) to
its off position and disconnect
the power cord from its
electric supply before
performing any assembly
procedures.
This Welder requires the attachment 1.
and use of a UL®-listed, 230 volt,
grounded, 3-prong, electrical Pow-
er Cord Plug (not included). Only a
qualied electrician should install the
Power Cord Plug. Never remove the
grounding prong or modify the Plug
in any way. Do not use adapter plugs
with this product.
Connect the Ground Clamp Cable2.
(23) to the Negative (--) Terminal (24).
(See Figure B.)
Connect the Electrode Holder Cable3.
(22) to the Positive (+) Terminal.
(See Figure B.)
WARNING
FIGURE A
21
12
24
11
9
18
19
FIGURE B
23
24
23
24
22

Page 10SKU 66042 For technical questions, please call 1-800-444-3353.
WORKPIECE AND WORK
AREA SET UP
Designate a work area that is clean1.
and well-lit. The work area must not
allow access by children or pets to
prevent injury and distraction.
The oor and surrounding area of 2.
your work site must not be am-
mable. A clean cement oor is rec-
ommended. The welding process
will eject molten metal slag onto the
oor, and it will scatter for 8 to 10 feet
or more in any direction. Have an
adequate re extinguisher available if
needed.
You must have a sturdy work table3.
that is open below the area you are
welding. Molten slag will be blown
through the workpiece, and must be
able to fall away freely.
Your work table must allow the work-4.
piece to be rmly clamped to prevent
it from accidentally moving or falling.
Route the Power Cord (21) along a5.
safe route to reach the work area
without creating a tripping hazard
or exposing the Power Cord to pos-
sible damage. The Power Cord must
reach the work area with enough
extra length to allow free movement
while working.
There must not be hazardous ob-6.
jects, such as utility lines or foreign
objects, nearby that will present a
hazard while working.
A barrier, such as a welding curtain7.
or welding shroud should be put up
to protect others in the work area and
limit the spray of sparks.
GENERAL OPERATING
INSTRUCTIONS
Protective gear
must be worn when
using the Welder.
ANSI-approved, arc shaded,
eye protection, a full face
shield, heavy-duty work
gloves, a welding apron,
respirator, and heavy-duty
work clothes without
pocketsshould be worn when
using this product. Do not
look at the ignited arc without
eye protection. Light from the
arc can cause permanent
damage to the eyes. Light
from the arc can burn the skin.
Do not breathe arc fumes.
The1. duty cycle denes the number
of minutes, within a 10 minute pe-
riod, during which a given Welder can
safely produce a particular current.
For example, this Welder, with a 100%
duty cycle at 65.0 Amps, means it
can operate continuously for 10 min-
utes at 65 Amps. Likewise, with a
25% duty cycle at 130 Amps means
the Welder can operate with rated
output for 2-1/2 minutes within a 10
minute working cycle. (See Figure C,
next page.)
DANGER