Miller Roughneck C Series User manual

300, 400, 500, And 600 Ampere MIG Welding Guns
Roughneck C-Series
Processes
Description
MIG (GMAW) Welding
OM-199 706A
August 2001
Visit our website at
www.MillerWelds.com

Flux Cored (FCAW) Arc
Welding
Semi-Automatic, Air-Cooled,
MIG (GMAW) Welding Gun

Miller Electric manufactures a full line
of welders and welding related equipment.
For information on other quality Miller
products, contact your local Miller distributor
to receive the latest full line catalog or
individual catalog sheets. To locate your nearest
distributor or service agency call 1-800-4-A-Miller,
or visit us at www.MillerWelds.com on the web.
Thank you and congratulations on choosing Miller.
Now you can get the job done and get it done right. We
know you don’t have time to do it any other way.
That’s why when Niels Miller first started building arc
welders in 1929, he made sure his products offered
long-lasting value and superior quality. Like you, his
customers couldn’t afford anything less. Miller
products had to be more than the best they could be.
They had to be the best you could buy.
Today, the people that build and sell Miller products continue the
tradition. They’re just as committed to providing equipment and service
that meets the high standards of quality and value established in 1929.
This Owner’s Manual is designed to help you get the most out of your
Miller products. Please take time to read the Safety precautions. They
will help you protect yourself against potential hazards on the worksite.
We’ve made installation and operation quick
and easy. With Miller you can count on years
of reliable service with proper maintenance.
And if for some reason the unit needs repair,
there’s a Troubleshooting section that will
help you figure out what the problem is. The
parts list will then help you to decide which
exact part you may need to fix the problem.
Warranty and service information for your
particular model are also provided.
Miller is the first welding
equipment manufacturer in
the U.S.A. to be registered to
the ISO 9001 Quality System
Standard.
Working as hard as you do
– every power source from
Miller is backed by the most
hassle-free warranty in the
business.
From Miller to You
Milleroffers a Technical
Manual which provides
more detailed service and
parts information for your
unit. To obtain a Technical
Manual, contact your local
distributor. Your distributor
can also supply you with
Welding Process Manuals
such as SMAW, GTAW,
GMAW, and GMAW-P.

TABLE OF CONTENTS
SECTION 1 – SAFETY PRECAUTIONS - READ BEFORE USING 1. . . . . . . . . . . . . . . . . . . . . . . . . . . .
SECTION 1 –SAFETY PRECAUTIONS FOR GMAW WELDING GUNS – READ BEFORE USING 1.
1-1. Symbol Usage 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1-2. GMAW Gun Hazards 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
EMF INFORMATION 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SECTION 2 – INSTALLATION 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2-1. Specifications 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2-2. Duty Cycle And Overheating 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2-3. Gun Connection And Operation 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SECTION 3 – MAINTENANCE & TROUBLESHOOTING 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3-1. Routine Maintenance 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3-2. Replacing The Contact Tip 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3-3. Installing Or Replacing The Liner 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3-4. Replacing Feeder Connector 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3-5. Installing Optional Gun Hook 199 662 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3-6. Installing Replacement Trigger 199 628 And Optional Locking Trigger 199 661 7. . . . . . . . . .
3-7. Troubleshooting 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SECTION 4 – PARTS LIST 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
OM-199 706
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 Section
25249.5 et seq.)

OM-199 706 Page 1
SECTION 1 –SAFETY PRECAUTIONS FOR GMAW
WELDING GUNS –READ BEFORE USING
SR7_7/01
1-1. Symbol Usage
Means Warning! Watch Out! There are possible hazards with this
procedure!The possible hazards are shown in the adjoining symbols.
This group of symbols means Warning! Watch Out! Possible ELECTRIC SHOCK and HOT PARTS hazards.
Consult symbols and related instructions below for necessary actions to avoid the hazards.
YMarks a special safety message.
.Means NOTE; not safety related.
1-2. GMAW Gun Hazards
WARNING
PROTECT YOURSELF AND OTHERS FROM POSSIBLE SERIOUS INJURY OR DEATH. KEEP CHILDREN
AWAY. PACEMAKER WEARERS KEEP AWAY UNTIL CONSULTING YOUR DOCTOR.
In welding, as in most jobs, exposure to certain hazards occurs. Welding is safe when precautions are taken. The
safety information given below is only a summary of the more complete safety information found in the wire feeder
and welding power source Owner’s Manuals. Read and follow all safety precautions.
HAVE ALL INSTALLATION, OPERATION, MAINTENANCE, AND REPAIR WORK PERFORMED ONLY BY
QUALIFIED PEOPLE.
GMAW WELDING can be hazardous.
ARC RAYS can burn eyes and skin.
1. Wear welding helmet with correct shade of filter.
2. Wear correct eye and body protection.
3. Cover exposed skin with spatter-resistant
clothing.
ELECTRIC SHOCK can kill.
1. Always wear dry insulating gloves.
2. Insulate yourself from work and ground.
3. Do not touch live electrode or electrical parts.
4. Repair or replace worn, damaged, or cracked
gun or cable insulation.
5. Turn off welding power source before changing
contact tip or gun parts.
6. Keep all covers and handle securely in place.
WELDING can cause fire or explosion.
1. Do not weld near flammable material.
2. Do not weld on closed containers.
3. Watch for fire; keep extinguisher nearby.
NOISE can damage hearing; SOME
APPLICATIONS, SUCH AS PULSING,
are noisy.
1. Check for noise level limits exceeding those
specifiedby OSHA.
2. Use approved ear plugs or ear muffs if noise level
is high.
3. Warn others nearby about noise hazard.
HOT SURFACES can burn skin.
1. Allow gun to cool before touching.
2. Do not touch hot metal.
3. Protect hot metal from contact by others.
FUMES AND GASES can be hazardous
to your health.
1. Keep your head out of the fumes.
2. Ventilate area, or use breathing device.
3. ReadMaterial Safety Data Sheets (MSDSs) and
manufacturer’s instructions for material used.
WELDING WIRE can cause puncture
wounds.
1. Keep hands and body away from gun tip when
triggeris pressed.
BUILD UP OF GAS can injure or
kill
1. Shutoff shielding gas supply when not in
use.
2. Always ventilate confined spaces or use
approvedair-supplied respirator.

OM-199 706 Page 2
EMF INFORMATION
The following is a quotation from the General Conclusions Section of
the U.S. Congress, Office of Technology Assessment, Biological
Effects of Power Frequency Electric & Magnetic Fields –
Background Paper, OTA-BP-E-53 (Washington, DC: U.S.
GovernmentPrinting Office, May 1989): “. . . there is now a very large
volume of scientific findings based on experiments at the cellular
level and from studies with animals and people which clearly
establishthat low frequency magnetic fields can interact with, and
produce changes in, biological systems. While most of this work is
of very high quality, the results are complex. Current scientific
understandingdoes not yet allow us to interpret the evidence in a
single coherent framework. Even more frustrating, it does not yet
allowus to draw definite conclusions about questions of possible risk
or to offer clear science-based advice on strategies to minimize or
avoid potential risks.”
To reduce magnetic fields in the workplace, use the following
procedures:
1. Keep cables close together by twisting or taping them.
2. Arrange cables to one side and away from the operator.
3. Do not coil or drape cables around the body.
4. Keep welding power source and cables as far away as practical.
5. Connect work clamp to workpiece as close to the weld as
possible.
About Pacemakers:
The above procedures are among those also normally
recommended for pacemaker wearers. Consult your doctor for
completeinformation.
Considerations About Welding And The Effects Of Low Frequency Electric And
Magnetic Fields
NOTE
mod10.1 4/93

OM-199 706 Page 3
SECTION 2 –INSTALLATION
2-1. Specifications
Air-CooledGuns For GMAW Welding
Note: Using mixed gases other than CO2reduces duty cycle ratings by 10-50%.
C-30 Gun Feeds .023 To 5/64 in (0.6 To 2.0 mm) Wire
Duty Cycle Rating:
100%: 300 A With CO2Shielding Gas
Weight With 15 Ft (Heaviest) Power Cable: 7.5 lb (3.4 kg)
Maximum Recommended Wire Size –5/64 in
C-40 Gun Feeds .023 To 5/64 in (0.6 To 2.0 mm) Wire
Duty Cycle Rating:
100%: 400 A With CO2Shielding Gas
Weight With 15 Ft (Heaviest) Power Cable: 10.3 lb (4.7 kg)
Maximum Recommended Wire Size –5/64 in
C-50 Gun Feeds .023 To 1/8 in (0.6 To 3.2 mm) Wire
Duty Cycle Rating:
100%: 500 A With CO2Shielding Gas
Weight With 15 Ft (Heaviest) Power Cable: 13 lb (5.9 kg)
Maximum Recommended Wire Size –1/8 in
Ref. ST-800 797-C C-60 Gun Feeds .023 To 1/8 in (0.6 To 3.2 mm) Wire
Duty Cycle Rating:
100%: 600 A With CO2Shielding Gas
Weight With 15 Ft (Heaviest) Power Cable: 14.5 lb (6.6 kg)
Maximum Recommended Wire Size –1/8 in
2-2. Duty Cycle And Overheating
Duty Cycle is percentage of 10 min-
utes that unit can weld at rated load
withoutoverheating.
Using mixed gases other than CO2
reduces duty cycle ratings 10–50%
depending on gas mixture and
weldingparameters.
YExceeding duty cycle can
damage unit and void
warranty.
100% Duty Cycle At Following Amperes:
C-30 Gun: 300 A With CO2Shielding Gas
C-40 Gun: 400 A With CO2Shielding Gas
C-50 Gun: 500 A With CO2Shielding Gas
C-60 Gun: 600 A With CO2Shielding Gas
Overheating
0
15
A or V
OR
Reduce Duty Cycle
Minutes
sduty1 5/95
ContinuousWelding

OM-199 706 Page 4
2-3. Gun Connection And Operation
802 631
1 Gun Securing Knob
2 Gun Block
3 Feeder Connector
Loosenknob. Insert feeder connec-
tor until it is as close as possible to
drive rolls without touching. Tighten
knob.
4 Gun Trigger Plug
5 Gun Trigger Receptacle
Insertplug into receptacle and tight-
en threaded collar.
6 Trigger Switch
Press switch to feed energized wire
and start gas flow.
6
2
5
4
1
3
SECTION 3 –MAINTENANCE & TROUBLESHOOTING
3-1. Routine Maintenance
YDisconnectpower
before maintaining. .Maintain more often
during severe conditions.
Each Spool Of Wire
Blow Out Gun
Casing
Clean
Nozzle
And Check
Contact Tip
3 Months
Replace
DamagedOr
Unreadable
Labels
Clean And
Tighten
Weld
Terminals
Replace Damaged
Gas Hose
Repair Or Replace
Cracked Cables
And Cords

OM-199 706 Page 5
Ref. 802 661
Turn off welding power source/wire
feeder. Cut off wire at contact tip.
1 Nozzle
2 Contact Tip
3 Diffuser
.Correctwire size is stamped on
tip. Be sure to use indicated
wire size.
Tools Needed:
12
3-2. Replacing The Contact Tip
3
802 648-A
Turn off welding power source/wire feeder.
Tools Needed:
3-3. Installing Or Replacing The Liner
1 Liner
2 FeederConnector
3 Nozzle
4 Contact Tip
5 Diffuser
6 Fiber Washer
7 Insulator
Lay gun cable out straight. Remove
washer, nozzle, tip, diffuser and in-
sulator. Remove existing liner from
adapter by unscrewing threaded
end of liner and removing liner from
gun cable.
Insert new liner into feeder connec-
tor and feed liner into connector.
Rotate threaded end of liner into
adapterto secure liner in place.
At opposite end of gun cable, cut lin-
er so 7/8 in extends beyond end of
gooseneckas shown. Reinstall in-
sulator, washer, diffuser, tip and
nozzle.
3
4
5
7
1
1
2
6
ThreadedEnd

OM-199 706 Page 6
Ref. 802 874 / 802 648
3-4. Replacing Feeder Connector
YTurn off welding power
source and wire feeder.
1 Nozzle
2 Contact Tip
3 Diffuser
4 Fiber Washer
5 Insulator
6 Liner
7 Feeder Connector
Lay gun cable out straight.
Remove nozzle, contact tip, diffus-
er, fiber washer, and insulator. Re-
moveexisting liner from feeder con-
nector by unscrewing threaded end
of liner and removing liner from gun
cable.
8 Screw
Remove screw. Move handle back
to reveal flatted side on handle in-
sert. Using wrenches on handle in-
sert and feeder connector, remove
feeder connector from insert.
Install new feeder connector.
.Gun cable must be straight
when new liner is inserted or
new liner will be cut to incorrect
length, causing wire feed
problems.
Insert new liner into new feeder
connectorand feed liner into feeder
connector. Rotate threaded end of
liner into feeder connector to se-
cure liner in place. Slide handle for-
ward and tighten screw.
At opposite end of gun cable, cut lin-
er so 7/8 in (22 mm) extends be-
yond end of gooseneck as shown.
Reinstallinsulator, fiber washer, dif-
fuser, tip and nozzle.
1
2
3
5
6
6
7
4
Threaded End
8
Flatted Side
7/8 in (22 mm)
Tools Needed:
5/8, 15/16
Old Feeder Connector
New Feeder Connector