INSTRUCTIONS for
F-11-964-H
January, 2016
Be sure this information reaches the operator.
You can get extra copies through your supplier.
ST-21M MIG WELDING TORCH
P/N 690509
These INSTRUCTIONS are for experienced operators. If you are not fully familiar with the principles of operation and safe prac-
tices for arc welding equipment, we urge you to read our booklet, “Precautions and Safe Practices for Arc Welding, Cutting,
and Gouging”, Form 52-529. Do NOT permit untrained persons to install, operate, or maintain this equipment. Do NOT attempt
to install or operate this equipment until you have read and fully understand these instructions. If you do not fully understand
these instructions, contact your supplier for further information. Be sure to read the Safety Precautions on page 2 before
installing or operating this equipment.
I. INTRODUCTION
The ST-21M (P/N 690509) is a liquid-cooled, in-line body
style, machine torch designed exclusively for mecha-
nized mig welding installations. The current carrying
capacity of this torch is 600 amperes continuous duty,
using all types of welding wire in sizes ranging from .030
inches (0.8 mm) through 7/64-inch (2.8 mm) diameters,
including ux cored wires.
The torch can be mounted directly to an EH-10A welding
head, and can be easily adapted for remote mounting.
The ST-21M is attached to the welding head by means
of an accessory mounting adaptor. To facilitate maneu-
verability and installation xturing, all service lines are
internally connected to the torch body and exit from the
rear of the torch barrel.
The torch is designed for use with either threadless
type contact tubes which are secured by a collet nut,
or threaded contact tips (see Table 2). The threadless
contact tube can be quickly and easily replaced by un-
screwing the metal nozzle and collet nut (in that order),
and then slipping the contact tube out. The threaded
tips can be replaced by removing the metal nozzle and
unscrewing the tip. Six metal nozzles (one for spot
welding use) are available for use with this torch (see
Table 1). Nozzle sizes 8 and 10 require a spatter liner.
NOTE: Due to the high electrical conductivity, use of tap
water or commercial anti-freeze is NOT recom-
mended for torch cooling. Use of the a coolant
circulator using a specially formulated torch
coolant (P/N 0560950312, 1 gal. container) is
recommended for torch cooling. The coolant
also provides anti-freeze protection down to
-34° F.
II. ACCESSORY EQUIPMENT
A. REQUIRED EQUIPMENT
1. Torch Mounting Bracket, P/N 633885. The bracket
includes as insulator sleeve which insulates the torch
from the welding head. See Figs. 1 and 2.
2. Nozzle and Wire Feed Accessories. The ST-21M
also requires a nozzle, a nozzle spatter liner, and
several wire feed accessories (contact tube or tip,
liner, and inlet guide tip) of the proper size for the wire
being used. These accessories are listed in Tables 1
and 2 following.
3. Service Line Connections and Extensions. De-
pending on mounting arrangements or welding head
to be used, there are several methods for connecting
the torch service lines to the gas, coolant, and power
supplies (see Fig. 4).
a. Connection block assembly (P/N 58V74) is avail-
able for mounting on the EH-10A welding head.
b. The following service lines and couplings are avail-
able:
Coolant Hose, 3-ft....................................................... 20634
Coolant Hose, 12-1/2-ft. .............................................40V76
Coolant Hose, 25-ft................................................... 406196
Gas Hose, 3-ft. ........................................................... 31504
Gas Hose, 12-1/2-ft. ...................................................40V77
Gas Hose, 25-ft. .........................................................34V38
Power Cable, 12-1/2-ft................................................40V78
Coolant Hose Coupling...............................................11N18
Gas Hose Coupling ....................................................11N17
Power Coolant Out Coupling ...................................... 11N19
Power Cable Adaptor.................................................. 45V11
Coolant Adaptor (connects hose to 1/4-in. NPT) ........ 11N16
4. Welding Head Accessories. Two other accessories
whose selection depends upon wire size and type,
are the feed roll and inlet guide insert on the welding
head. Selection of these accessories is covered in
the instruction booklet supplied with the welding head.
Mounting bracket, Part No. 996497, can be used to
mount an EH-10 to adjustable slide P/N 25V39 (Fig.
2) or to user designed set-up.
2
WARNING: These Safety Precautions are for your
protection. They summarize precautionary infor-
mation from the references listed in Additional
Safety Information section. Before performing any
installation or operating procedures, be sure to read and follow
the safety precautions listed below as well as all other manuals,
material safety data sheets, labels, etc. Failure to observe Safety
Precautions can result in injury or death.
PROTECT YOURSELF AND OTHERS -- Some welding, cutting,
and gouging processes are noisy and re-
quire ear protection. The arc, like the sun,
emits ultraviolet (UV) and other radiation
and can injure skin and eyes. Hot metal
can cause burns. Training in the proper
use of the processes and equipment is essential to prevent
accidents. Therefore:
1. Always wear safety glasses with side shields in any work area,
even if welding helmets, face shields, and goggles are also
required.
2. Use a face shield tted with the correct lter and cover plates
to protect your eyes, face, neck, and ears from sparks and rays
of the arc when operating or observing operations. Warn by-
standers not to watch the arc and not to expose themselves
to the rays of the electric-arc or hot metal.
3. Wear ameproof gauntlet type gloves, heavy long-sleeve
shirt, cuess trousers, high-topped shoes, and a welding
helmet or cap for hair protection, to protect against arc rays
and hot sparks or hot metal. A ameproof apron may also be
desirable as protection against radiated heat and sparks.
4. Hot sparks or metal can lodge in rolled up sleeves, trouser
cus, or pockets. Sleeves and collars should be kept buttoned,
and open pockets eliminated from the front of clothing
5. Protect other personnel from arc rays and hot sparks with a
suitable non-ammable partition or curtains.
6. Use goggles over safety glasses when chipping slag or grind-
ing. Chipped slag may be hot and can y far. Bystanders should
also wear goggles over safety glasses.
FIRES AND EXPLOSIONS -- Heat from ames and arcs can
start res. Hot slag or sparks can also cause res and explo-
sions. Therefore:
1. Remove all combustible materials
well away from the work area or cover the
materials with a protective non-ammable
covering. Combustible materials include wood,
cloth, sawdust, liquid and gas fuels, solvents,
paints and coatings, paper, etc.
2. Hot sparks or hot metal can fall through cracks or crevices in
oors or wall openings and cause a hidden smoldering re
or res on the oor below. Make certain that such openings
are protected from hot sparks and metal.“
3. Do not weld, cut or perform other hot work until the workpiece
has been completely cleaned so that there are no substances
on the workpiece which might produce ammable or toxic
vapors. Do not do hot work on closed containers. They may
explode.
4. Have re extinguishing equipment handy for instant use,
such as a garden hose, water pail, sand bucket, or portable
re extinguisher. Be sure you are trained in its use.
5. Do not use equipment beyond its ratings. For example, over-
loaded welding cable can overheat and create a re hazard.
SAFETY PRECAUTIONS
10/98
6. After completing operations, inspect the work area to make
certain there are no hot sparks or hot metal which could cause
a later re. Use re watchers when necessary.
7. For additional information, refer to NFPA Standard 51B, "Fire
Prevention in Use of Cutting and Welding Processes", available
from the National Fire Protection Association, Batterymarch
Park, Quincy, MA 02269.
ELECTRICAL SHOCK -- Contact with live electrical parts and
ground can cause severe injury or death. DO NOT use AC
welding current in damp areas, if movement is conned, or if
there is danger of falling.
1. Be sure the power source frame
(chassis) is connected to the ground system of
the input power.
2. Connect the workpiece to a good
electrical ground.
3. Connect the work cable to the workpiece. A poor or missing
connection can expose you or others to a fatal shock.
4. Use well-maintained equipment. Replace worn or damaged
cables.
5. Keep everything dry, including clothing, work area, cables,
torch/electrode holder, and power source.
6. Make sure that all parts of your body are insulated from work
and from ground.
7. Do not stand directly on metal or the earth while working
in tight quarters or a damp area; stand on dry boards or an
insulating platform and wear rubber-soled shoes.
8. Put on dry, hole-free gloves before turning on the power.
9. Turn o the power before removing your gloves.
10. Refer to ANSI/ASC Standard Z49.1 (listed on next page) for
specic grounding recommendations. Do not mistake the
work lead for a ground cable.
ELECTRIC AND MAGNETIC FIELDS — May be dangerous. Electric
current owing through any conductor causes localized Electric
and Magnetic Fields (EMF). Welding and cutting current creates
EMF around welding cables and welding machines. Therefore:
1. Welders having pacemakers should
consult their physician before welding. EMF
may interfere with some pacemakers.
2. Exposure to EMF may have other
health eects which are unknown.
3. Welders should use the following
procedures to minimize exposure to EMF:
A. Route the electrode and work cables together. Secure them
with tape when possible.
B. Never coil the torch or work cable around your body.
C. Do not place your body between the torch and work cables.
Route cables on the same side of your body.
D. Connect the work cable to the workpiece as close as
possible to the area being welded.
E. Keep welding power source and cables as far away from
your body as possible.
3
FUMES AND GASES -- Fumes and gases,
can cause discomfort or harm, particu-
larly in conned spaces. Do not breathe
fumes and gases. Shielding gases can
cause asphyxiation. Therefore:
1. Always provide adequate ventilation in the work area by
natural or mechanical means. Do not weld, cut, or gouge on
materials such as galvanized steel, stainless steel, copper,
zinc, lead, beryllium, or cadmium unless positive mechani-
cal ventilation is provided. Do not breathe fumes from these
materials.
2. Do not operate near degreasing and spraying operations.
The heat or arc rays can react with chlorinated hydrocarbon
vapors to form phosgene, a highly toxic gas, and other irritant
gases.
3. If you develop momentary eye, nose, or throat irritation
while operating, this is an indication that ventilation is not
adequate. Stop work and take necessary steps to improve
ventilation in the work area. Do not continue to operate if
physical discomfort persists.
4. Refer to ANSI/ASC Standard Z49.1 (see listing below) for
specic ventilation recommendations.
5. WARNING: This product, when used for welding or cut-
ting, 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.)
CYLINDER HANDLING -- Cylinders, if mis-
handled, can rupture and violently release
gas. Sudden rupture of cylinder, valve, or
relief device can injure or kill. Therefore:
1. Use the proper gas for the process
and use the proper pressure reducing regula-
tor designed to operate from the compressed
gas cylinder. Do not use adaptors. Maintain hoses and ttings
in good condition. Follow manufacturer's operating instruc-
tions for mounting regulator to a compressed gas cylinder.
2. Always secure cylinders in an upright position by chain or
strap to suitable hand trucks, undercarriages, benches, walls,
post, or racks. Never secure cylinders to work tables or xtures
where they may become part of an electrical circuit.
3. When not in use, keep cylinder valves closed. Have valve pro-
tection cap in place if regulator is not connected. Secure and
move cylinders by using suitable hand trucks. Avoid rough
handling of cylinders.
4. Locate cylinders away from heat, sparks, and ames. Never
strike an arc on a cylinder.
5. For additional information, refer to CGA Standard P-1, "Precau-
tions for Safe Handling of Compressed Gases in Cylinders",
which is available from Compressed Gas Association, 1235
Jeerson Davis Highway, Arlington, VA 22202.
EQUIPMENT MAINTENANCE -- Faulty or im-
properly maintained equipment can cause
injury or death. Therefore:
1. Always have qualied personnel perform
the installation, troubleshooting, and maintenance work. Do
not perform any electrical work unless you are qualied to
perform such work.
2. Before performing any maintenance work inside a power
source, disconnect the power source from the incoming
electrical power.
3. Maintain cables, grounding wire, connections, power cord,
and power supply in safe working order. Do not operate any
equipment in faulty condition.
4. Do not abuse any equipment or accessories. Keep equipment
away from heat sources such as furnaces, wet conditions such
as water puddles, oil or grease, corrosive atmospheres and
inclement weather.
5. Keep all safety devices and cabinet covers in position and in
good repair.
6. Use equipment only for its intended purpose. Do not modify
it in any manner.
ADDITIONAL SAFETY INFORMATION -- For more
information on safe practices for electric arc weld-
ing and cutting equipment, ask your supplier for
a copy of "Precautions and Safe Practices for Arc
Welding, Cutting and Gouging", Form 52-529.
The following publications, which are available from
the American Welding Society, 550 N.W. LeJuene Road, Miami,
FL 33126, are recommended to you:
1. ANSI/ASC Z49.1 - "Safety in Welding and Cutting"
2. AWS C5.1 - "Recommended Practices for Plasma Arc Welding"
3. AWS C5.2 - "Recommended Practices for Plasma Arc Cutting"
4. AWS C5.3 - "Recommended Practices for Air Carbon Arc Goug-
ing and Cutting"
5. AWS C5.5 - "Recommended Practices for Gas Tungsten Arc
Welding“
6. AWS C5.6 - "Recommended Practices for Gas Metal Arc Weld-
ing"“
7. AWS SP - "Safe Practices" - Reprint, Welding Handbook.
8. ANSI/AWS F4.1, "Recommended Safe Practices for Welding and
Cutting of Containers That Have Held Hazardous Substances."
MEANING OF SYMBOLS - As used throughout
this manual: Means Attention! Be Alert! Your
safety is involved.
Means immediate hazards which, if not
avoided, will result in immediate, serious
personal injury or loss of life.
Means potential hazards which could
result in personal injury or loss of life.
Means hazards which could result in minor
personal injury.
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5
g. Empêchez l’apparition de toute humidité, notamment sur
vos vêtements, à la surface de l’emplacement de travail,
des câbles, du porte-électrode et du poste de soudage/
coupage. Réparez immédiatement toute fuite d’eau.
4. VENTILATION-- La respiration prolongée des fumées
résultant des opérations de soudage/coupage, à l’inté-
rieur, d’un local clos, peut provoquer des malaises et
des dommages corporels. Aussi convient-il d’observer
les précautions suivantes:
a. Assurez en permanence une aération adéquate de
l’emplacement de travail en maintenant une ventilation
naturelle ou à l’aide de moyens mécaniques. N’effec-
tuez jamais de travaux de soudage ou de coupage
sur des matériaux de zinc, de plomb, de beryllium ou
de cadmium en l’absence de moyens mécaniques de
ventilation capables d’empêcher l’inhalation des fumées
dégagées par ces matériaux.
b. N’effectuez jamais de travaux de soudage ou de cou-
page à proximité de vapeurs d’hydrocarbure chloré
résultant d’opérations voisines de dégraissage ou de
pulvérisation. La chaleur dégagée ou le rayonnement
de l’arc peut déclencher la formation de phosgène --
gaz particulièrement toxique -- et d’autres gaz irritants,
à partir des vapeurs de solvant.
c. Une irritation momentanée des yeux, du nez ou de la
gorge constatée au cours de l’utilisation de l’équipe-
ment dénote un défaut de ventilation. Arrêtez-vous de
travailler an de prendre les mesures néces- saires
à l’amélioration de la ventilation. Ne poursuivez pas
l’opération entreprise si le malaise persiste.
d. Certaines commandes comportent des canalisations
où circule de l’hydrogène. L’armoire de commande est
munie d’un ventilateur destiné à empêcher la forma-
tion de poches d’hydrogène, lesquelles présentent un
danger d’explosion; ce ventilateur ne fonctionne que si
l’interrupteur correspondant du panneau avant se trouve
placé en position ON (Marche). Veillez à manœuvrer
cette commande en vériant si le couvercle est bien en
place, de façon à assurer l’efcacité de la ventilation
ainsi réalisée. Ne jamais débrancher le ventilateur.
e. Les fumées produites par l’opération de soudage ou
de coupage peuvent s’avérer toxiques. Aussi est-il
nécessaire de disposer en permanence d’un dispositif
adéquat de ventilation de type aspirant, an d’élimi-ner
du voisinage de l’opérateur tout dégagement de fumée
visible.
f. Consultez les recommandations particulières en matière
de ventilation indiquées à l’alinéa 6 de la norme Z49.1
de l’AWS.
5. ENTRETIEN DE L’ÉQUIPEMENT-- Un équipement
entretenu de façon défectueuse ou inadéquate risque
non seulement de réaliser un travail de mauvaise qualité
mais, chose plus grave encore, d’entraîner des dom-
mages corporels graves, voire mortels en déclenchant
des incendies ou des chocs électriques. Observez par
conséquent les précautions suivantes:
a. Efforcez-vous de toujours coner à un personnel qua-li-
é l’installation, le dépannage et l’entretien du poste de
soudage et de coupage. N’effectuez aucune réparation
électrique sur l’équipement à moins d’être qua-lié à
cet effet.
b. Ne procédez jamais à une tâche d’entretien quelconque
à l’intérieur du poste de soudage/coupage, avant d’avoir
débranché l’alimentation électrique.
c. Maintenez en bon état de fonctionnement les câbles, le
câble de masse, les branchements, le cordon d’alimen-
tation et le poste de soudage/coupage. N’utilisez jamais
le poste ou l’équipement s’il présente une défectuosité
quelconque.
d. Prenez soin du poste de soudage et de coupage et
des équipements accessoires. Gardez-les à l’écart des
sources de charleur, notamment des fours, de l’humidi-
té, des aques d’eau maintenez-les à l’abri des traces
d’huile ou de graisse, des atmosphères corrosives et
des intempéries.
e. Laissez en place tous les dispositifs de sécurité et tous
les panneaux de l’armoire de commande en veillant à
les garder en bon état.
f. Utilisez le poste de soudage/coupage conformément
à son usage prévu et n’effectuez aucune modication.
6. INFORMATIONS COMPLÉMENTAIRES RELATIVES
À LA SÉCURITÉ--
Pour obtenir des informations complémentaires sur
les règles de sécurité à observer pour le montage et
l’utilisation d’équipements de soudage et de coupage
électriques et sur les méthodes de travail recomman-
dées, demandez un exemplaire du livret N° 52529 “Pre-
cautions and Safe Practices for Arc Welding, Cutting and
Gouging” publié par ESAB. Nous conseillons également
de consulter les publications sui-vantes, tenues à votre
disposition par l’American Welding Society, 550 N.W.
LeJuene Road, Miami, FL 32126:
a. “Safety in Welding and Cutting” AWS Z49.1
b. “Recommended Safe Practices for Gas-Shielded Arc
Welding “AWS A6. 1.
c. “Safe Practices for Welding and Cutting Containers That
Have Held Combustibles” AWS-A6.0.
d. “Recommended Safe Practices for Plasma Arc Cutting”
AWS-A6. 3.
e. “Recommended Safe Practices for Plasma Arc Welding”
AWS-C5. 1.
f. “Recommended Safe Practices for Air Carbon Arc Gou-
ging and Cutting” AWS-C5. 3.
g. “Code For Safety in Welding and Cutting” CSA-Standard
W117. 2.
6
Table 2 - ST-21M Wire Feed Accessories
Contact Tip Torch
Wire Wire Contact (Threaded) Torch Inlet
Type Size Tube Long Short Liner Guide
HARD .030 — — 632791 690515 (.070) 690516
.035 996104 632794 632793 690515 (.070) 690516
.045 996105 632796 632795 690514 (.100) 690516
.052 996816 948335 948308 690514 (.100) 690516
1/16 996106 632798 632797 690514 (.100) 690516
3/32 996108 — 632800 993844 (.140) 690516
CORED (a) .045 996105 — 632795 690514 (.100) 690516
.052 996816 — 948308 690514 (.100) 690516
1/16 996106 — 632797 690514 (.100) 690516
3/32 996108 — 632800 993844 (.140) 690516
7/64 (c) — — 633611 — 11N73
SOFT .030 — — 632791 6271087 (.070) (b) 690516
.035 996104 632794 632793 6271087 (.070) (b) 690516
3/64 996105 632796 632795 993843 (.110) 690516
1/16 996106 632798 632797 993843 (.110) 690516
3/32 996108 — 633611 993901 (.138) 690516
(a) Use No. 12M nozzle (P/N 997310) for cored wire.
(b) Also requires a support tube liner, (P/N 993901).
(c) A drawback to using this size wire is that a torch liner cannot be used and wire guide wear can occur.
5. Power Cable. Customer supplied 4/0 power cable
with connector lug (P/N 81F60).
6. Coolant Circulator - A unit capable of circulating
coolant at the rate of 1 gpm at 50 psi is more than
adequate for protecting the torch. The Coolant circula-
tor should be capable of providing at least 6400 BTU/
hr cooling capacity at 40°C ambient temperature.
The use of p/n 0560950312 TORCH Coolant 50%
EG 1GAL is recommended in the coolant circulator.
NOTE: The circulator cannot be set up for solenoid
valve shutoff.
Table 1 - ST-21M Nozzles
No. 8 .......................................................................598739*
No. 10 .....................................................................598721*
No. 10L (Long Length) ...........................................598891*
No. 12 ...................................................................... 633985
No. 12L (Long Length) ............................................ 639756
No. 12M (Med. Length) ........................................... 997310
No. 12 Spot ............................................................. 993757
* Requires Spatter Liner 633603.
B. OPTIONAL ACCESSORIES
1. Remote Mounting Accessories. If remote mount-
ing of torch is desired, conduit, conduit liner (if using
aluminum wire), torch-to-conduit adaptor (61N59 and
welding head wire outlet guide are required. Refer to
Fig. 2 and Tables 3 and 4 for the proper accessories.)
2. Cold Wire Accessories. After-market cold wire feed
systems and accessories can be used with the ST-
21M. The torch body is 1-3/8" dia., a typical size for
automatic torches, holders, and accessories.
3. Centering Bushing, Part No. 994330 (for use with 8
and 10 nozzles). Eliminates any possibility of spatter
bridging in the torch. This is accomplished by using
this one-piece centering bushing/spatter liner in place
of the two individual pieces normally used. Note that it
can only be used at maximum currents of 350 amps
with Argon or 550 amps with CO
2
.
7
2. Insert a torch liner (and support liner, if used) through
the mounting bracket on the rear of torch until it is
rmly seated within the torch.
3. Slip a torch inlet guide tip, of the proper size, over the
protruding end of the liner and screw it into the end
of the mounting bracket.
4. With the insulator sleeve (14N14) in place over the
mounting bracket (step 1-d), insert the bracket into
the clamp on the accessory support assembly of the
welding head. Secure the bracket by tightening the
locking handle on support assembly clamp. Connect
the service lines to plumbing box, connection block,
or directly to supply sources using service line exten-
sions and couplings where necessary.
Table 4 - Wire Feed Accessories for Remote Mounting
NOTE: See Tables 1 and 2 for nozzle and contact tube/tip requirements.
Wire Conduit* Wire Outlet Guide Outlet
Wire Size Torch Conduit Guide
type in. Liner 4-ft. 6-ft. 10-ft. Liner** EH-10A Insert
HARD .045 690514 38V86 39V99 40V18 None 39N15† None
.052 690514 38V86 39V99 40V18 None 39N15† None
1/16 690514 38V86 39V99 40V18 None 39N15† None
5/64 993844 38V89 40V01 — None 62N17†† None
3/32 993844 38V80 39V83 40V20 None 62N17†† None
CORED .045 690514 38V86 39V99 40V18 None 39N15† None
.052 690514 38V86 39V99 40V18 None 39N15† None
1/16 690514 38V86 39V99 40V18 None 39N15† None
5/64 993844 38V89 40V01 — None 62N17†† None
3/32 993844 39V80 39V83 40V20 None 62N17†† None
7/64 — 39V80 39V83 40V20 None 39N16 None
SOFT 3/64 993901 38V89 40V01 — 42V74 29N13 05N57
1/16 — 39V80 39V83 40V20 42V75 29N13 12N75
3/32 — 39V80 39V83 40N20 42V73 29N13 05N58
* Requires adaptor, P/N 61N59, in place of torch inlet guide tip (on torch mounting bracket).
** Conduit liners must be cut to the proper length to allow 1/16-in. clearance between liner and contact tube.
† Includes replaceable sleeve (995692).
†† Includes replaceable sleeve (995693)
III. INSTALLATION
Depending on the choice of mounting system used,
either direct or remote, install the wire feed components
as outlined below and illustrated in Figures 1 and 2.
A. DIRECT MOUNTING TO EH-10A WELDING HEAD
(Refer to Figs. 1 and 3)
1. Install the torch mounting bracket (accessory part No.
633885) on the ST-21M as follows:
a. Loosen (and if necessary, remove) the setscrew
located in the recessed hole at the rear of the torch
barrel.
b. Place the small spacer tube (633887, supplied)
into the conduit connection tting at the rear of the
torch barrel, and tighten the setscrew to secure the
tube.
c. Slip the mounting bracket, large end rst, over
the rear torch barrel and the attached spacer and
then, using the 1/4-in. capscrew supplied, tighten
the bracket around the torch barrel.
d. Place the insulator sleeve (14N14, supplied) over
the end of the mounting bracket.
8
*ADAPTOR (PART OF
CONN. BLK. ASSY).
TORCH MOUNTING
BRACKET - 633885
ST-21M MIG MACHINE
TORCH - 690509
ADJUSTABLE SLIDE
25V39
MOUNTING PLATE
493195
TORCH MOUNTING
BRACKET - 633885
ST-21M MIG MACHINE
TORCH - 690509
Fig. 1 - ST-21M Torch Direct Mounting Fig. 2 - ST-21M Torch Remote Mounting
5. With the nozzle and contact tube removed and wire
in the feed rolls, use the inching switch on the control
to feed wire through the mounting bracket and torch
until it protrudes from the end of the torch.
6. Select the correct contact tube or tip. If using contact
tube, slip the tube and collet nut (632811) over the
wire, and screw the nut into the torch to hold the tube
in place.
7. Place a spatter liner (633603, if one is required) in
the proper size nozzle and install into the front end
of the torch.
B. REMOTE MOUNTING
Follow the steps as described above in section III-A.
except in step 3, install adaptor (61N59) in place of torch
inlet guide tip. The torch is then mounted to mounting
bracket (see Fig. 2) and conduit (with conduit liner
installed if required) is to be connected to torch and to
wire outlet guide on welding head.
IV. ADJUSTMENT AND OPERATION
Before adjustments are made, disengage the pressure
roll to prevent wire from feeding and arcing to an acci-
dental ground. To set the shielding gas ow rate, press
the weld start button to open the gas solenoid valve and
adjust the owmeter to the desired ow rate.
Make sure the coolant system is completely lled, and
be sure to plug in the coolant recirculator before operat-
ing the torch.
Specic operation of the torch depends on the particular
wire feeder with which it is to be used. Therefore, consult
the instruction booklet supplied with the wire feeder.
When changing wires — switch to one of different size
and composition — make sure you refer to the wire Feed
Accessories Table. The listed parts are to be used for a
particular wire size — DO NOT SUBSTITUTE PARTS.
* If desired, the adaptor and the lug can be switched to the opposite sides
of the connection block.
CONNECTION BLOCK
ASSY - 58V74
WELDING
HEAD
TORCH INLET
GUIDE TIP
(SEE TABLE 2)
MOUNTING
BRACKET -
996497
CONDUIT (See Table 4)
ADAPTOR - 61N59
CONDUIT LINER
(SEE TABLE 4)
TO WELDING HEAD
(See Table 4)
9
V. MAINTENANCE & REPLACEMENT PARTS
A. POWER CABLE
If the power cable assembly becomes damaged, it is rec-
ommended that (1) a new one be purchased, or (2) the
damaged unit be turned over to ESAB authorized repair
station for repair. The connection ttings are crimped on
at the factory by special crimping tools to ensure strong
connections and prevent leakage. A satisfactory job
cannot be done without these tools.
B. GAS AND COOLANT HOSE ASSEMBLIES
(Refer to Fig. 3)
If shielding gas or coolant hose assemblies require
replacement, loosen the two No. 10—32 x 3/16-in. set
screws on the locking nut and pull back barrel.
To replace a gas hose assembly, proceed as follows:
1. Clip off wire hose clamp (53N46) and remove hose.
2. Clean off the tting, and then brush on some 3M type
1711 adhesive onto the tting.
3. Slide new wire hose clamp on the new hose and insert
the hose over the grooved sealing area of the hose
tting on the torch.
4. Using a pair of pliers, pull on the hose clamp tightly
over the grooved sealing surface and apply 1/2 twist.
Be sure to position the wire hose clamp so that the
twist does not interfere with another part or the inside
of the handle.
5. Reposition the pliers about 1/8-in. from the hose and
twist an additional 1-1/2 turns.
6. Snip off excess wire about 1/8-in. from hose and bend
the twisted ends as shown below.
To replace the coolant hose assembly, proceed as fol-
lows:
1. Snip off the ear of the hose clamp by cutting into the
sides with pliers. Then remove hose.
2. Clean off the tting, and then brush on some 3M type
1711 adhesive onto the tting.
3. Slide hose clamp (950626 - supplied with hose as-
sembly) over the new hose assembly.
4. Push the new hose onto the short coolant connection
tube of the torch body and tube assembly. Position
the hose clamp over the grooved section of the short
tube.
5. Crimp the ear of the hose clamp with pincers as il-
lustrated below.
6. Rotate the hose clamp so that the ear is positioned
close to the power connection tube as shown in sec-
tion “A-A” of Figure 3.
ST-21M MACHINE
TYPE MIG TORCH
690509
SETSCREW - #10-32 X 3/16" (61330907)
(Supplied with 997032) (Align hole in barrel over setscrew.)
CLAMP - 950626
LOCKING NUT - 598787
INSULATING SLEEVE - 633880
NOZZLE (ACCESSORY)
(SEE TABLE 1)
CENTERING BUSHING - 17782
NOZZLE BODY - 633881
WIRE GUIDE, BODY & TUBE ASS'Y - 997032
INCLUDES:
WIRE GUIDE INSULATOR - 997031
A
CLAMP - 53N46
TORCH MOUNTING BRACKET - 633885
INCLUDES
SPACER - 633887
INSULATOR SLEEVE - 14N14
ACCESSORY
COOLANT HOSE
ASSY. - 17980
(29-IN. LG.)
5/8"-18 L. H.
includes:
CLAMP - 950626
POWER CABLE
ASS'Y. - 46V12
(24-IN. LG.)
7/8"-14 L. H.
GAS HOSE
ASS'Y. - 17981
(26 - 1/2-IN. LG.)
CONDUIT
POWER/COOLANT OUT
GAS
COOLANT HOSE CLAMP
(position as shown)
Sect. A-A
EH-10 WELDING HEAD
INSULATOR SLEEVE
14N14 (SUPPLIED WITH
633885)
MOUNTING BRACKET
633885
CONNECTION BLOCK
ASS'Y. - 58V74
(SHOWN ATTACHED
TO EH-10 HEAD)
SPACER - 633887
(SUPPLIED WITH
633885)
MOUNTING ARRANGEMENT OF
ST-21 M MACHINE TORCH TO
EH-10 WELDING HEAD
5/8" — 18
CAPSCREW - 1/4"-20 X 5/8"
(Supplied with 633885)
1 3/8"
DIA.
A
(2) SETSCREW - 10-32 X 3/16" (61330907)
GASKET - 633884
END
FITTING-
996403
(Supplied with 997032)
1/8" NPT
SPATTER LINER
(SEE TABLE 1)
COLLET NUT 632811
CONTACT TUBE (ACCESSORY)
(SEE TABLE 2)
TORCH INLET
GUIDE TIP &
TORCH LINER
(ACCESSORY)
(SEE TABLE 2)
996300
SUPPLIED
CENTERING BUSHING
REMOVAL TOOL
BARREL - 690524
10
TORCH GAS
TORCH POWER
(& Coolant Out)
TORCH COOLANT IN
PLUMBING
BOX
996067
GAS HOSE*
COOLANT HOSE*
COOLANT HOSE*
TO GAS
WC-9 or WC-8C
COOLANT
CIRCULATOR
OPTIONAL COOLANT HOSE ADAPTOR - 11N16
(Connects Hose to 1/4-in. NPT)
POWER
SOURCE
4/0 POWER CABLE
(Customer Supplied)
TORCH GAS
TORCH POWER
(& Coolant Out)
TORCH COOLANT IN
GAS HOSE*
COOLANT HOSE*
TO GAS
POWER
SOURCE
(Customer Supplied)
4/0 POWER CABLE
COOLANT HOSE*
OPTIONAL ADAPTOR - 11N16
CONN.
BL’K
ASSY.
58V74
WELDING
HEAD
CONNECTOR - 2062310
(Supplied with Plumbing Box)
ELBOW - 999849
(Supplied with Conn. Box)
(& Coolant Out)
WC-9 or WC-8C
COOLANT
CIRCULATOR
TORCH COOLANT
COOLANT HOSE*
TO GAS
GAS HOSE*
TORCH GAS
TORCH POWER
COOLANT HOSE*
11N18
11N17
45V11
OPTIONAL ADAPTOR - 11N16
COUPLINGS
POWER
SOURCE
4/0 POWER CABLE
(Customer Supplied)
NOTE:
ALL SERVICE LINES MAY BE
EXTENDED, USING COUPLINGS:
11N17 (GAS)
11N18 (COOLANT)
11N19 (POWER/COOLANT OUT)
*AVAILABLE SERVICE LINES
COOLANT HOSE, 3-FT. ....................................20634
COOLANT HOSE, 12-1/2-FT. ............................40V76
COOLANT HOSE, 25-FT. ..................................406196
GAS HOSE, 3 -FT.............................................. 31504
GAS HOSE, 12-1/2-FT. ..................................... 40V77
GAS HOSE, 25-FT............................................. 34V38
POWER CABLE, 12-1/2-FT. .............................. 40V78
Fig. 4 - ST-21M Service Line Connection Diagram
CAUTION: Do not clean the liner while it is assembled
in the conduit. The solvent will attack and
destroy the conduit’s rubber covering.
C. CONDUIT LINER (For remote mounting installa-
tions only.)
The plastic lined conduit liners (42V73, 42V74, and
42V75) used to feed aluminum should be cleaned
periodically to remove any accumulation of dust or dirt.
A solvent, such as oxylene (trichlorotriuoroethane,
CCL
3
CF
3
) should be forced through the conduit and
then blown out with air. Flushing the solvent through
the conduit 5 or 6 times will be sufcient. The solvent
can be purchased from the J.B. Moore Corp., Nutley,
New Jersey.
WC-9 or WC-8C
COOLANT
CIRCULATOR
11
D. NOZZLES
Nozzle spatter will be minimal and will wipe off easily
due to efcient nozzle cooling. If necessary, occasional
tightly adhering spatter can be removed from the inside
of nozzles with a hand reamer or le. Exercise care not
to damage the spatter liner or that spatter does not drop
back into the nozzle or contact tube. Ideally, the nozzle
should be removed for cleaning. Adherence of spatter
can be removed for cleaning. Adherence of spatter can
be further minimized and removal made easier by thinly
coating the inside of the nozzle with No. 65 Nozzle Com-
pound (4 oz. can - 08N65; 1 qt. can - 08N75). If spatter
liner is damaged or cracked it should be replaced.
E. CENTERING BUSHING
(Refer to Fig. 3.)
To remove the centering bushing (17782) for replace-
ment or inspection purposes, proceed as follows:
1. Turn off power supply.
2. Unscrew nozzle (and collet nut, if necessary) and
remove contact tube.
3. Insert centering bushing removal tool 996300, (sup-
plied with torch assembly) through two adjacent bush-
ing slots and then hook over two opposite bushing
ribs. The centering bushing can then be removed by
pulling the tool straight out.
F. GASKET, INSULATOR AND END FITTING
(Refer to Fig. 3.)
To remove gasket (633884), insulator (997031) or wire
guide end tting (996403) for replacement or inspection
purposes, proceed as follows:
1. With power supply turned off, disconnect all torch
service lines.
2. Remove nozzle, contact tube, and collet nut or contact
tip.
3. Loosen the two setscrews on locking nut (598787)
and pull back torch barrel (mounting bracket attached)
enough to allow the locking nut to rotate freely.
4. Unscrew the locking nut from the nozzle body
(633881).
5. Pull nozzle body away from the wire guide assembly
(997032). The centering bushing (17782) will fall free.
6. Check the gasket for cracks and deformed sealing
surfaces. When replacing the old or installing a new
gasket, apply a thin lm of Dow Corning DC 111
silicone grease (73585007) or equivalent to the O.D.
and sealing surfaces of the gasket.
To reassemble the gasket for proper seating over the
pliable silicone rubber insulator (997031), pull the
insulator out partially and then slide the gasket over
the insulator until the side of the gasket, that will seat
against the torch body, and the end of the insulator
are ush. Push the gasket and insulator together until
the gasket is properly seated against the torch body.
7. To remove the wire guide end/tting (996403), clamp
the torch body in a vise or use a vise-grip type pliers
on the wire guide and then unscrew the end tting
using a 7/16-in. open-end wrench. Before installing
a new tting, apply a thin lm of Dow Corning Heat
Sink Compound No. 340 (73585976) to both the male
and female threads.
Note: much smaller amounts are available commercially.
8. Reassemble the torch in reverse order.
IF YOU DO NOT KNOW WHOM TO CALL
Telephone: (800) ESAB-123/ Fax: (843) 664-4452/ Web:http://www.esab.com
Hours: 7:30 AM to 5:00 PM EST
A. CUSTOMER SERVICE QUESTIONS:
Order Entry Product Availability Pricing Delivery
Order Changes Saleable Goods Returns Shipping Information
Eastern Distribution Center
Telephone: (800)362-7080 / Fax: (800) 634-7548
Central Distribution Center
Telephone: (800)783-5360 / Fax: (800) 783-5362
Western Distribution Center
Telephone: (800) 235-4012/ Fax: (888) 586-4670
B. ENGINEERING SERVICE: Telephone: (843) 664-4416 / Fax : (800) 446-5693
Welding Equipment Troubleshooting Hours: 7:30 AM to 5:00 PM EST
Warranty Returns Authorized Repair Stations
C. TECHNICAL SERVICE: Telephone: (800) ESAB-123/ Fax: (843) 664-4452
Part Numbers Technical Applications Hours: 8:00 AM to 5:00 PM EST
Performance Features Technical Specications Equipment Recommendations
D. LITERATURE REQUESTS: Telephone: (843) 664-5562 / Fax: (843) 664-5548
Hours: 7:30 AM to 4:00 PM EST
E. WELDING EQUIPMENT REPAIRS: Telephone: (843) 664-4487 / Fax: (843) 664-5557
Repair Estimates Repair Status Hours: 7:30 AM to 3:30 PM EST
F. WELDING EQUIPMENT TRAINING:
Telephone: (843)664-4428 / Fax: (843) 679-5864
Training School Information and Registrations Hours: 7:30 AM to 4:00 PM EST
G. WELDING PROCESS ASSISTANCE:
Telephone: (800) ESAB-123 / Fax: (843) 664-4454 Hours: 7:30 AM to 4:00 PM EST
H. TECHNICAL ASST. CONSUMABLES:
Telephone : (800) 933-7070 Hours: 7:30 AM to 5:00 PM EST
ESAB Welding & Cutting Products, Florence, SC Welding Equipment
COMMUNICATION GUIDE CUSTOMER SERVICES
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