AGM 250C User manual

AGM Pin Welder
Instruction Manual
Model 250C
AGM Industries, Inc.
16 Jonathan Drive, Brockton, MA 02301
TEL: [phone] FAX: [phone]
www.agmind.com
Read equipment manufacturer’s manual before using this product. Failure to do so can result in
serious injury or death.

2
TABLE OF CONTENTS
Subject Page
1. Description of accessories 3
2. Installing & removing collets, stops, etc. 5
3. Disassembly of weld gun 10
4. Diagram & parts list 11
5. Weld gun Set-Up Sheets
Welding Steel and Stainless Steel weld pins 12
Welding Aluminum weld pins 13
Welding pins over 7” long 14
Welding flanged Steel and Stainless Studs up to 1/4-20 diameter 15
Welding flanged and Non-Flanged Aluminum studs. Non-flanged 16
Steel and Stainless studs through 1/4-20 diameter. (All
welders except JS-1 320SS & LS-400)
Welding Non-Flanged Steel and Stainless Studs through 1/4-20 17
diameter (JS-1,320SS & LS-400 only)
Alternate set-up for welding studs over 1-3/8” long 18
Welding studs 5/16” diameter and larger 19
Welding Cupped head/Mini-cup Pins 22
Welding Powerbase Pins 25
Welding to a curved surface 27
Welding through a template 28
Spec. for a typical template 29
6. Approximate Voltage Settings & Ground Polarity
Mild or Stainless Steel base / Mild or Stainless Steel pins or studs 30
Galvanized Steel base / Mild or Stainless Steel pins or studs 31
Aluminum base / Aluminum pins or studs 32

3
Model 250C Weld Gun
The AGM Model 250C weld gun is a semi-automatic, contact welding tool that has been
carefully engineered and designed for use with a wide variety of AGM accessories.
Given normal care and use, this weld gun will require very little maintenance. When
repairs are required, the complete disassembly of the weld gun can be accomplished in a
matter of minutes.
Following is a description of the various accessories available. The application sheets list
the recommended accessories and their part numbers.
COLLET* - This is always required for welding. It is very important that the correct
size be used and that it is in good condition. A loose fitting collet will cause arcing on
the stud or pin and possibly cause poor welds.
COLLET PROTECTOR* - This is used when welding flanged studs or weld pins. It
allows you to weld various lengths of studs or pins without changing the gun set up. It
also helps to keep splatter away from the collet. It is important the collet protector be
used whenever recommended. Protectors are not required when using stops, except when
welding Powerbase pins.
STOP* - This is required when welding non-flanged studs, or when the adjustable foot
assembly is used. Its purpose is to back up the pin or stud to prevent it from being
inserted too far into the gun. The Model 250C gun utilizes two types of stops; the 437G
and the 250C-G. Both are easily installed.
COLLET ADAPTER ASSEMBLY - This is used as a holder for the collets, stops and
collet protectors. It allows for rapid interchange of collets and it is easily removed by the
tapered wedge that is supplied with the gun.
It has been found to be good practice to keep extra collets, protectors, stops and adapters
on hand.
LEGS - They are used to provide correct weld gun spring pressure while keeping the
stud or pin perpendicular to the work. They are normally mounted 120 degrees apart on
the weld gun face plate.
LEG SUPPORT RING - This is used when welding on a curved surface, such as
corrugated metals or round tanks. It is placed over the three legs, and aligns the stud or
pin when the ring is held firmly against the work.
ADAPTER RING - This is used to extend the three legs for certain applications, such as
when a longer collet protector is used to weld aluminum pins.
* Specify stud or pin diameter and length when ordering.

4
(CONTINUED)
Model 250C Weld Gun
(CONTINUED)
ADJUSTABLE FOOT ASSEMBLY - This is necessary when welding Powerbase pins
and large diameter studs and may also be used for welding very long CD pins. It is used
in conjunction with a stop and spark shield to stabilize the pin or stud.
SPARK SHIELD* - This protects the collet, collet adapter assembly, etc. from weld
splatter, while stabilizing the pin or stud during the weld cycle. It will require occasional
cleaning and periodic replacement.
* Specify stud or pin diameter and length when ordering.

5
Model 250C Weld Gun
(CONTINUED)
INSTALLATION AND REMOVAL PROCEDURES
INSTALLING COLLET AND COLLET PROTECTOR
A. Examine the inside of the collet adapter assembly for pitted areas or splatter.
Clean by scraping with a sharp object, or replace if necessary.
B. Insert the collet into the collet adapter assembly, making sure that it seats against
the shoulder.
C. Locate the two (2) collet holding set screws and tighten them securely. These
screws should be checked daily for tightness.
D. Slide the collet protector over the collet adapter assembly, making sure that it
seats properly. Tighten the set screws securely.
COLLET REMOVAL
A. Remove the collet protector by loosening the two (2) protector holding set screws
approximately 1-1/2 turns.
B. Loosen both collet holding set screws approximately 1-1/2 turns.
C. Grasp the collet by its end and remove it.
If you have difficulty removing the collet, the following procedures may be
helpful:
1. Manually rotate the collet.
2. Insert the proper size stud or pin into the collet and attempt to remove the
collet and fastener together.
3. If the above suggestions do not work, pliers may be used. Insert the
proper size pin or stud into the collet and rotate until the collet is loose.

6
Model 250C Weld Gun
(CONTINUED)
INSTALLING TYPE 437G STOP
A. Place the stop inside the rear of the collet.
B. Insert the collet, with stop, into the collet adapter assembly.
C. Locate and tighten the collet holding set screws, as previously described.
D. DO NOT use a collet protector.
INSTALLING TYPE 250C-G STOP
A. Remove end cap and stop nut from rear of weld gun.
B. Insert stop inside gun shaft.
C. Screw stop nut down securely over the end of the shaft.
D. Replace end cap onto gun housing.
E. DO NOT use a collet protector.
F. See chart on the next page for stop numbers.

7
250C-G TYPE STOP
STUD LENGTH CATALOG NUMBER STOP LENGTH
1/4” – 5/16” 250C-G-*-0250 7”
3/8” – 7/16” -0375 6.875”
1/2” – 9/16” -0500 6.750”
5/8” -0625 6.625”
3/4” -0750 6.500”
7/8” -0875 6.375”
1” -1000 6.250”
1-1/4” -1250 6.000”
1-1/2” -1500 5.750”
1-3/4” -1750 5.500”
1-7/8” -1875 5.375”
2” -2000 5.250”
2-1/4” -2250 5.000”
2-1/2” -2500 4.750”
2-3/4” -2750 4.500”
2-7/8” -2875 4.375”
3” -3000 4.250”
3-1/4” -3250 4.000”
3-1/2” -3500 3.750”
3-7/8” -3875 3.375”
4” -4000 3.250”
4-1/2” -4500 2.750”
4-7/8” -4875 2.375”
5” -5000 2.250”
5-1/2” -5500 1.750”
5-7/8” -5875 1.375”
6” -6000 1.250”
6-1/2” -6500 0.750”
7” -7000 0.250”
437G TYPE STOP
STUD LENGTH CATALOG NUMBER STOP LENGTH
** 3/16” 437G-*-0187 1.230”
** 1/4” -0250 1.168”
** 5/16” -0312 1.106”
** 3/8” -0375 1.043”
7/16” -0437 0.981”
1/2” -0500 0.918”
9/16” -0562 0.856”
5/8” -0625 0.793”
3/4” -0750 0.668”
7/8” -0875 0.543”
1” -1000 0.418”
1-1/8” -1125 0.293”
1-1/4” -1250 0.168”
1-3/8” -1375 0.043”
*Specify diameter of stud (i.e. 6-32, 8-32, 10-32 etc.)
** Requires 375-SP series collet for studs 3/8” long and shorter.

8
MODEL 250-C WELD GUN
INSTALLATION OF COLLET ADAPTER ASSEMBLY
This procedure can be accomplished with a collet and stop, or collet protector already
installed.
A. Before installing, be sure that the tapered surface of the collet adapter and shaft
assembly are clean. Wipe with a clean cloth if necessary.
B. Insert the collet adapter assembly into the shaft assembly, turning the adapter as it
is pushed down. This will ensure that it is seated securely.
REMOVAL OF COLLET ADAPTER ASEMBLY
A. Slide the rubber dust boot toward the faceplate to expose the shaft assembly.
B. Insert the tapered wedge between the shaft assembly and the collet adaptor
assembly. The flat side of the wedge should go toward the shaft.
C. Tap the wedge lightly to release the adapter assembly from the tapered seat of the
gun shaft.

9
MODEL 250-C WELD GUN
INSTALLING OR CHANGING SPRING
A. Unscrew the end cap from the gun housing.
B. Unscrew stop nut from the end of gun shaft.
C. Unscrew the spring retainer and remove the washer from the housing.
D. Remove the spring from the shaft.
E. Slide the desired spring over the shaft.
F. Replace the washer onto the end of the gun housing.
G. Screw the spring retainer into the housing.
H. Screw the stop nut onto the end of the gun shaft.
I. Screw the end cap onto the gun housing.

10
MODEL 250C WELD GUN
DISASSEMBLY OF THE WELD GUN
A. Remove handle cover screws (items 28, 29 & 45)
B. Lift off the handle cover (item 38)
C. Remove the nut, washer and cap screw (items 34, 35 & 36) from the welding lead
(item 40)
D. Remove the control wires (items 32 & 33) from the trigger switch (item 37) and
remove the switch from the handle
E. Lift out the welding and control lead assemblies (items 40 & 30), from the handle
F. Loosen the cap screw of the cable clamp assembly (item 39) and slide both wires
out of the clamp
G. Unscrew the end cap (item 1) from the gun housing
H. Unscrew the stop nut (item 15) from the end of the shaft
I. Unscrew the knurled spring retainer (item 17) from the gun housing
J. Remove the washer (item 3)
K. Remove the spring (item 4) from the gun shaft
L. Unscrew the three (3) screws (items 9 & 22) from the housing
M. Remove the collet adaptor assembly and dust boot (items 25 & 12) from the shaft
assembly (item 6)
N. Check to be sure there are no burrs on the end of the gun shaft. If necessary use a
file or emery paper to smooth it off. Slide the face plate (item 10) off of shaft
assembly
O. Slide the shaft assembly (item 6) out of the gun housing, making sure the pigtail
assembly (item 7) feeds through the slot in the housing and handle.
To assemble the gun repeat these operations in the reverse order.

11
2615-M ADAPTER ASSEMBLY INCLUDES ITEMS #25, 13, 14 &24

12
SET UP FOR WELDING STEEL/STAINLESS STEEL WELD PINS
GUN SET UP WITH HEAVY (3”) SPRING & 1151-M STATIONARY LEGS
1. 12 & 10 gauge pins to galvanized steel
A. Install collet and protector as described on page 3. Refer to the chart below
for part numbers. Be sure the collet holding set screws are tightened securely.
Install (3) 1151-M stationary legs into the equally spaced threaded holes in the
faceplate.
B. Welding cables should be connected for “Reverse Polarity”
(Ground to “Negative”).
2. 12 & 10 gauge pins to un-plated steel /stainless steel
A. Set up gun as described above.
B. Welding cables should be connected for “Straight Polarity”
(Ground to “Positive”).
For welding pins over 7” in length, see page 13.
Steel/Stainless Collet Collet
Weld Pin Protector
12 Ga. (2.69mm) 437-106 437-P-106
10 Ga. (3.42mm) 437-135 437-P-135
Note: 1. Cables - Ground………………………………………………....1142-E (#6)
Gun Lead Extension……………………………………1279-E (#6)
WELDING PROCEDURE
Set voltage and ground polarity as directed on Page 30 or 31. Once the pin is loaded into
the gun, position on the work piece and depresses the gun until the stationary legs contact
the base metal. While holding the gun firm and steady, pull the trigger. Remove the gun
from the welded pin in a straight line motion so as not to bend the pin or damage the
collet and protector.

13
SET UP FOR WELDING ALUMINUM WELD PINS
GUN SET UP WITH HEAVY (3”) SPRING & 2367-M ADAPTER ASSEMBLY
A. If previously installed, remove legs (2) and dust boot from gun.
B. Install proper collet (5) and protector (4), being sure collet holding set screws
are tightened securely.
C. Place adapter ring (1) over face plate and line up the two clearance holes with
the corresponding tapped holes in the face plate. Install the two socket head
cap screws (6) and tighten securely.
D. Insert a leg (2) into each of the three equally spaced tapped holes in the
adapter ring.
E. Slide the leg support ring (3) over the ends of the three legs. The metal
inserts should face down towards the legs. This ring ensures proper alignment
of the gun when welding to curved or narrow surfaces.
For welding pins over 7” in length, see Page 13.
LEGEND DESCRIPTION PART NO. QTY.
1** Adapter Ring 1358-M-XL 1
2** Legs 1151-M 3
3** Leg Support Ring 1628-M 1
4 Collet Protector 437-P-*AL 1
5 Collet 437-*AL 1
6** Cap Screw 1212-M-0750 2
* Specify pin diameter when ordering these items.
** Part of 2367-M Adapter Assembly
Aluminum
WELD PIN Collet / Protector Base Material Ground Polarity Approximate Welding Voltage
12 Ga. (2.69mm) 437-106AL
437-P-106AL Embossed Aluminum POS. 200
10 Ga. (3.42mm) 437-135AL
437-P-135AL Embossed Aluminum POS. 215
Note: 1. Cables - Ground ……………………………………………….1142-E (#6)
Gun Lead Extension…………………………………..1279-E (#6)
WELDING PROCEDURE
Set voltage and ground polarity as directed on page 32. Once the pin is loaded into the
gun, position on the work piece and depress until the leg support ring rests on the base
metal. While holding the gun firm and steady, pull the trigger. Remove the gun from the
welded pin in a straight line motion, so as not to bend the pin or damage the collet and
protector.
CAUTION: Take care not to move the gun once put to the work, as this could damage the
tip of the pin and cause poor welds.

14
SET UP FOR WELDING PINS OVER 7” LONG
GUN SET UP WITH HEAVY (3”) SPRING & 2318-M FOOT PIECE ASSEMBLY
A. Install proper collet (2), stop (1) and protector (3), being sure collet holding
set screws are tightened securely. See pages 12 or 13 for part numbers.
B. If previously installed, remove legs (1151-M) from face place.
C. Insert adjustable legs (9) of foot piece assembly into the holes provided in the
face plate.
D. Insert proper spark shield (5) into the foot piece (8) and tighten set screws (4).
Be sure to install with concave side facing away from the gun, as shown.
E. Insert weld pin through spark shield and into the collet until it rests against the
stop.
F. Adjust the foot piece by loosening the two set screws (10) and sliding the
assembly as required. The pin should extend beyond the spark shield
approximately 1/4” as shown. Once set tighten the set screws securely.
G. Check for freedom of movement between the spark shield and the weld pin.
If they bind, loosen the two cap screws (6) and move the foot piece until the
pin is centered in the spark shield. Once set, tighten the cap screws securely.
Items 4,6,7,8, & 9 Part of 2318-M Foot Piece Assembly
WELDING PROCEDURE
Set voltage and ground polarity as directed on page 30, 31, or 32. Once the pin is loaded
into the gun, position on the work piece and depress the gun until the spark shield rests on
the base metal. While holding the gun firm and steady, pull trigger. Remove the gun
from the welded pin in a straight line motion so as not to bend the pin or damage the
collet and protector.

15
SET UP FOR WELDING FLANGED STEEL & STAINLESS STUDS THROUGH
1/4-20 DIAMETER
GUN SET UP WITH HEAVY (3”) SPRING & 1151-M STATIONARY LEGS
A. Install collet and protector as described on page 3. Be sure the collet holding
set screws are tightened securely. Install (3) 1151-M stationary legs into the
equally spaced threaded holes in the face plate.
B. Refer to the chart below for collet and collet protector part numbers. For
studs that are 3/8” long and shorter, use the type 375-SP collet with
appropriate 437G- type stop. DO NOT use a collet protector.
Steel / Stainless Collet Collet
Flanged Stud Protector
4-40 (M2.8) 437-110 437-P-110
6-32 (M3) 437-136 437-P-136
8-32 (M4) 437-159 437-P-159
10-24/32 (M5) 437-185 437-P-185
1/4-20 (M6) 437-246 437-P-246
Navy (3/16”) 437-177 437-P-177
Notes: 1. Cables - Ground…… ………………………………..1142-E (# 6 Standard)
Gun Lead Extension…………………….…………....1279-E (# 6 Standard)
2. For alternate gun set up to weld studs longer than 1-3/8”, see page 17.
WELDING PROCEDURE
Set Voltage and ground polarity as directed on page 30 or 31. Once the stud is loaded
into the gun, position on the work piece and depress the gun until the stationary legs
contact the base metal. While holding the gun firm and steady, pull trigger. Remove the
gun from the weld stud in a straight line motion so as not to bend the stud or damage the
collet and protector.

16
SET UP FOR WELDING FLANGED & NON-FLANGED ALUMINUM STUDS
AND HANGER STUDS (ALL WELDERS) & NON-FLANGED
STEEL/STAINLESS STUDS THROUGH ¼-20 DIAMETER (ALL WELDERS
EXCEPT 320SS, LS-400 & JS-1 WILL NOT WELD ¼-20 ALUMINUM STUDS)
GUN SET UP WITH HEAVY (3”) SPRING & 1151-M STATIONARY LEGS
A. Install collet and stop as described on pages 5 & 6. Be sure the collet holding
set screws are tightened securely. Do not use a protector. Install (3) 1151-M
stationary legs into the equally spaced threaded holes in the face plate.
B. Refer to the chart below for collet part numbers. For studs 3/8” long and
shorter, use the type 375-SP collet.
C. Use the type 437G-* stop for studs up to 1-3/8” long, and type 250CG-* for
studs over 1-3/8” long. See page 7 for stop part numbers. See page 18 for an
alternate set up for welding studs over 1-3/8” longs.
* Specify stud length and diameter when ordering stops.
Stud Size Collet
4-40 (M2.8) 437-110
6-32 (M3) 437-136
8-32 (M4) 437-159
10-24/32 (M5) 437-185
*** 1/4-20 (M6) 437-246
Hanger 437-HS**
Navy (3/16”) 437-177
Notes: 1. Cables - Ground…………………………………………..1142-E (#6)
Gun Lead Extension…………………………….1279-E (#6)
2. ** - Stop part number for the hanger stud is 437G-HS.
3. *** - When welding flanged 1/4-20 aluminum studs, the 2506-M-200 medium
spring and 2526-M spring locator installed in the end cap is
recommended, in addition to the 2506-M-300 heavy internal spring.
To weld aluminum studs onto small pieces, special grounding techniques
may have to be used. Please consult the factory.
WELDING PROCEDURE
Set the voltage and ground polarity as directed on page 30, 31, or 32. Once the stud is
loaded into the gun, position it on the work piece and depress until the stationary legs
contact the base metal. While holding the gun firm and steady, pull the trigger. Remove
the gun from the welded stud in a straight line motion so as not to bend the stud or
damage the collet.

17
SET UP FOR WELDING NON-FLANGED STEEL & STAINLESS STUDS
THROUGH 1/4-20 DIAMETER (JS-1 320SS & LS-400 ONLY)
GUN SET UP WITH HEAVY (3”) & MEDIUM (2”) SPRING & 1151-M LEGS
A. Install collet and stop as described on pages 5 & 6. Be sure the collet holding
set screws are tightened securely. Do not use a protector. Install (3) 1151-M
stationary legs into the equally spaced threaded holes in the faceplate.
B. Refer to the chart below for collet part numbers. For studs 3/8” long and
shorter, use the type 375-SP collet.
C. Use the type 437G-* stop for studs up to 1-3/8” long, and type 250CG-* for
studs over 1-3/8” long. See page 7 for stop part numbers. See page 17 for an
alternate set up for welding studs over 1-3/8” long.
D. Remove end cap (1) from gun barrel.
E. Place medium spring (3) over stop nut (4).
F. Insert spring locator (2) into end cap, as shown, and replace cap onto gun
barrel.
Stud Size Collet
4-40 (M2.8) 437-110
6-32 (M3) 437-136
8-32 (M4) 437-159
10-24/32 (M5) 437-185
1/4-20 (M6) 437-246
WELDING PROCEDURE
Set voltage and ground polarity as directed on page 30 or 31. Once the stud is loaded
into the gun, position it on the work piece and depress until the stationary legs contact the
base metal. While holding the gun firm and steady, pull the trigger. Remove the gun
from the welded stud in a straight line motion so as not to bend the stud or damage the
collet.

18
ALTERNATE GUN SET UP FOR STUDS OVER 1-3/8” LONG
GUN SET UP WITH HEAVY (3”) SPRING & 2318-M FOOT PIECE ASSEMBLY
A. Install proper stop (1), collet (2) and protector (3), being sure the collet
holding set screws are tightened securely. See the chart below and previous
page for part numbers.
B. If previously installed, remove the 1151-M legs from the face plate.
C. Insert adjustable legs (9) of the foot assembly into the holes provided on the
face plate.
D. Insert the proper spark shield (5) into the foot piece (8) and tighten the set
screws (4).
E. Insert the stud through the spark shield, protector and into the collet, until it
rests against the stop.
F. Check for freedom of movement between the spark shield and the stud. If
they bind, loosen the two cap screws (6) and move the foot piece until the stud
is centered in the spark shield. Once done, retighten the cap screws securely.
G. Adjust the foot piece by loosening the two set screws (10) and sliding the
assembly as required. The stud should extend beyond the spark shield
approximately 1/4” as shown. Once done, retighten the set screws securely.
The gun is now ready for welding.
Items 4,6,7,8, & 9 Part of 2318-M Foot Piece Assembly

19
SET UP FOR WELDING 5/16” DIAMETER AND LARGER STUDS
GUN SET UP WITH HEAVY (3”) SPRING (SEE NOTE ON NEXT PAGE) AND
2318-M FOOT PIECE ASSEMBLY
(SEE PAGE 21 FOR ALTERNATE SET UP USING 2958-M FOOT PIECE
ASSEMBLY)
A. Install proper stop (1) and collet (2), being sure that the collet holding set
screws are tightened securely. Refer to the chart on the next page for collet
part numbers, and to Note 2 for the stop part numbers.
B. If previously installed, remove 1151-M legs from the face plate.
C. Insert adjustable legs (8) of the foot piece assembly into the holes provided on
the face plate.
D. Insert proper spark shield (4) (see Note 3 for part number) into foot piece (7)
and tighten the set screws (3).
E. Insert stud through spark shield and into the collet until it rests against the
stop.
F. Check for freedom of movement between the spark shield and the stud. If
they bind, loosen the two cap screws (5) and move the foot piece until the stud
is centered in the spark shield. Once done, retighten the cap screws securely.
G. Adjust the foot piece by loosening the two set screws (9) and sliding the
assembly as required. The stud should extend beyond the spark shield
approximately 1/4” as shown. Once done, tighten the set screws securely.
The gun is now ready for welding.
(Continued)

20
SET UP FOR WELDING 5/16” DIAMETER AND LARGER STUDS
(continued)
Stud Size Collet
5/16-18 (M8) 437-S-307
5/16” Shoulder 437-S-312
3/8-16 (M10) 437-S-370
1/2-13 (M13) 437-S-495
Notes: 1. When welding flanged & non-flanged 5/16-18 and larger aluminum studs, the
2506-M-200 medium spring and 2526-M spring locator installed in the end cap
is recommended, in addition to the 2506-M-300 heavy internal spring.
To weld aluminum studs onto small pieces, special grounding techniques may
have to be used. Please consult the factory.
2. Stop requirements
A. For all SL516 shoulder studs, use 437SG-1375.
B. For all other 5/16-18 & larger threaded studs over 1” long, use the
437SG-1000 stop. Specify stud length for studs under 1” long (i.e. for
S51618-1216L stud (3/4” long), use 437SG-0750 stop).
3. Spark shield requirements
A. For studs 2-1/2” long & shorter, use 2144-M-250 shield.
B. For studs over 2-1/2” long, use 2144-M-300-dia.
Specify stud diameter when ordering this spark shield.
4. Cables
A. Ground…………………………………….1507-E (#2 Heavy Duty)
B. Gun Lead Extension……………………….1506-E (#2 Heavy Duty)
WELDING PROCEDURE
Set voltage and ground polarity as directed on page 30, 31, or 32. Once the stud is loaded
into the gun, position on the work piece and depresses the gun until the park shield
contacts the base metal. While holding the gun firm and steady, pull the trigger. Remove
the gun from the welded stud in a straight line motion so as not to bend the stud or
damage the collet.
Preparation of the weld surface is strongly recommended for this application. The weld
area should be ground clean of all rust, scale, paint, etc. to ensure strong, reliable welds.