Alpha Professional Tools PSG-125 User manual

16 Park Dr Ste 9, Franklin, NJ 07416 • 800-648-7229
www.alpha-tools.com
MANUAL
Part No: 5480-1304
Version 10/2022
Alpha® PSG-125 Wet
Cutting Kit
Instruction Manual
Blade Guard
Loc-Line Assembly Garden Hose
Connection
* TOOL INCLUDED
Hook & Loop Strap
PSG-125*
Memory Wrap
Water Hose
Water Quick Coupler
with Shut-O󰀨 Valve

2PSG-125 5” PNEUMATICANGLE GRINDER
TABLE OF CONTENTS
Introduction..........................................................................................4
About the Symbols ..............................................................................4
Safety Instructions for Pneumatic Tools ..............................................5
PSG-125 Overview..............................................................................7
Specications.................................................................................7
Equipment Included.............................................................................8
Additional Precautions for Using the Pneumatic Angle Grinder ..........9
Air Pressure and Volume..............................................................10
Rust Protection.............................................................................10
Cleaning the Rotor Assembly.......................................................10
How to Add the Rust Inhibitor Oil ................................................. 11
Filter/Regulator System.....................................................................12
Connecting the Air Supply.................................................................12
Spindle Size.......................................................................................13
Sound Level.......................................................................................13
Attaching the Safety Guard ...............................................................13
Mounting Diamond Wheels ...............................................................14
Attaching the Side Handle.................................................................15
Operation...........................................................................................16
Throttle Operation ........................................................................16
Exhaust Vent ................................................................................16
Optional Wet Cutting....................................................................17
PSG-125 Pneumatic Angle Grinder Schematic.................................18
PSG-125 Pneumatic Angle Grinder Parts List...................................19
Additional Hoses (Air Hose) ..............................................................21
Accessories and Factory Service ......................................................27
Product Registration..........................................................................26

3
PSG-125 5” PNEUMATICANGLE GRINDER
TABLE OF CONTENTS
SERVICE
Use only Alpha Professional Tools®accessories and spare parts.
Should components which have been described need to be
exchanged, please contact your dealer orAlpha Professional Tools®.
NEED MORE INFORMATION
For information onAlpha Professional Tools®complete product line, visit us on the web at
www.alpha-tools.com.
CAUTION!
• Attach the Wet Blade Cutting Kit correctly by following the
procedure in this instructional manual.
• During operation, be sure to wear personal safety equipment.
WBC6KIT Schematics........................................................................22
WBC6KIT Parts List............................................................................22
Instructions.........................................................................................22
Installation of WBC6KIT Guard ..........................................................23
Hook & Loop Strap Installation...........................................................24
Installation of EasyOn-EasyO󰀨 Sleeve...............................................24
Connecting the Water Supply.............................................................25
For a Tool Compatibility Chart, visit our website.

4PSG-125 5” PNEUMATICANGLE GRINDER
INTRODUCTION
Thankyou for purchasinganAlpha®PSG-125WetCutting Kit. Pleaseread
this instruction manual thoroughly to ensure safe and correct use of the
Pneumatic Angle Grinder. Keep this manual in a place where operators
can access it easily whenever necessary.
ABOUT THE SYMBOLS
According to the hazard level, all safety notes in this manual are
classied into “DANGER”, “WARNING”, and “CAUTION”.
DANGER! Death or serious personal injury is imminent when
handling this pneumatic angle grinder incorrectly.
WARNING! There is a possibility of death or serious personal
injury when handling this pneumatic angle grinder
incorrectly.
CAUTION! There is a possibility of personal injury or property
damage when handling this pneumatic angle
grinder incorrectly.
Note: In some situations, failing to observe WARNING notes could result
in death or serious personal injury. Be sure to read and observe
the safety notes to ensure safety and correct use of the pneumatic
angle grinder.

5
PSG-125 5” PNEUMATICANGLE GRINDER
SAFETY INSTRUCTIONS FOR POWER TOOLS
1. KNOW YOUR POWER TOOL. Read owner’s manual carefully.
Learn its applications and limitations as well as specic potential
hazards particular to this tool.
2. KEEP WORK AREA CLEAN. Cluttered areas and benches invite
accidents.
3. AVOID DANGEROUS ENVIRONMENTS. Keep work areas as dry
as possible. Do not use tool in presence of ammable liquids or
gases. Keep the area well lit.
4. KEEP CHILDRENAND VISITORSAWAY. All visitors should be kept
a safe distance from the work area. Keep out of reach of children.
5. DON’T FORCE TOOL. It will do the job better and safer at the rate
for which it was designed.
6. WEAR PROPER APPAREL. Do not wear loose clothing or jewelry
as it can get caught in moving parts. Rubber gloves and insulated
non-skid footwear are recommended. Wear protective covering to
contain long hair.
7. WEAR PROPER EYE PROTECTION. All users and bystanders
mustalways wearproperpersonal eyeprotection which conformwith
ANSI/ISEAZ87.1 (CAN/CSAZ94.3).Also use a face or dust mask if
operation is dusty. Always wear certied safety equipment.
8. WEAR PROPER EAR PROTECTION. All users and bystanders
mustwearproper personal ear protection which conforms withANSI
S12.6 (S3.19) hearing protection.
9. WEAR PROPER RESPIRATORY PROTECTION. All users and
bystandersmust wear proper personalrespiratory protection.Always
use NIOSH/OSHA approved respiratory protection appropriate for the
dust exposure.
Warning: Some dust created by power sanding, sawing, grinding, drilling,
polishing and other construction activities contains chemicals known to the
State of California to cause cancer, birth defects, or other reproductive harm.
Some examples of these chemicals are:
- Lead from lead-based paints
- Crystalline silica from bricks, cement and other masonry products, and
- Arsenic and chromium from chemically-treated lumber.

6PSG-125 5” PNEUMATICANGLE GRINDER
Your risk from these exposures varies, depending on how often you do this
type of work. To reduce your exposure, work in a well ventilated area, and
work with approved safety equipment, such as dust masks that are specially
designed to lter out microscopic particles.
To familiarize with the risks associated with a material, consult with your
employer, manufacturer/supplier and government agencies regarding the
hazards of the materials and their recommendations to protect yourself.
10. DON’TABUSEAIR SUPPLY HOSE. Don’tcarry tool bysupply hose
or expose to tra󰀩c areas where it can be crushed.
11. ALWAYS SECURE WORK PIECE. Use clamps or a vise to hold
work. It’s safer than using your hand and it frees both hands to
operate tool.
12. DON’T OVERREACH. Keep properfooting and balance atall times.
13. DISCONNECT TOOLS WHEN NOT IN USE. Always disconnect
tool before servicing when changing blades.
14. REMOVE ADJUSTING KEYS AND WRENCHES. Form a habit of
checking to see that keys and adjusting wrenches are removed from
tool before turning it on.
15. MAINTAIN TOOLS WITH CARE. Keep tools clean at all times for
best and safest performance. Follow instructions for lubricating and
changing accessories. Keep handles dry, clean and free of oil or
grease. Inspect moving parts for alignment and binding as well as
for breakage and improper mounting.
16. AVOIDACCIDENTAL STARTING. Do not carry a “connected” tool,
or make adjustments, or change discs without making sure the tool
is disconnected from the air supply.
17. USE ONLY RECOMMENDED ACCESSORIES. The use of any
accessories other than what is listed or recommended for this
particular tool may be hazardous.
18. KEEP HANDS AWAY FROM ALL MOVING PARTS.
19. USE SIDE HANDLES. Supplied with tool for control and safety.
20. STAY ALERT. Watch what you are doing and use common sense.
Do not operate tool when you are tired, or under the inuence of
medication or alcohol.

7
PSG-125 5” PNEUMATICANGLE GRINDER
SPECIFICATIONS:
Air Pressure.............................................................................90 PSI
Air Consumption Max. ........................................33 CFM / 934 L/Min
No Load RPM..........................................................................12,000
Weight.........................................................................4.6 lbs (2.1 kg)
Length......................................................................11-3/4” (298mm)
Air Inlet..............................................................................3/8” NPSM
Spindle.................................................................................... 5/8”-11
Max. Disc Capacity..................................................... 5” x 1/4” x 7/8”
Max HP....................................................................................1.4 HP
5” PNEUMATIC ANGLE GRINDER OVERVIEW
Figure 1

8PSG-125 5” PNEUMATICANGLE GRINDER
1. Inner Flange for Grinding...................................................1 pc
2. Lock Nut for Grinding.........................................................1 pc
3. Side Handle ......................................................................1 pc
4. Hex. Wrench (1/4”).............................................................1 pc
5. Pin Wrench.........................................................................1 pc
6. Double Open-End Wrench (1” / 32mm) .............................1 pc
7. Rust Inhibitor Oil (8oz / 237ml) (AIR-008)..........................1 pc
8. Safety Guard Assembly .....................................................1 pc
9. Air Hose Assembly (15ft / 4.5m) ........................................1 pc
10. Handle Bracket ..................................................................1 pc
11. Washer & Seal Set (M12) ..................................................2 pc
12. Screw (M12 x 16)...............................................................1 pc
13. Inner Flange for Cutting.....................................................1 pc
14. Lock Nut for Cutting...........................................................1 pc
15. Height Adjustment Spacer .................................................1 pc
EQUIPMENT INCLUDED
Figure 2

9
PSG-125 5” PNEUMATICANGLE GRINDER
ADDITIONAL PRECAUTIONS FOR USING
THE PNEUMATIC ANGLE GRINDER
In addition to the general safety notes described on the preceding pages,
please read and observe the following precautionary notes before using
the pneumatic grinder .
DANGER!
INSTRUCTIONS
AlphaProfessionalTools® provides the highest quality parts and manufactur-
ingtechniquesinthemanufacture ofthis tool.In ordertoobtainthemaximum
e󰀨ectiveness and provide the highest degree of safety, it is necessary to
review and follow these instructions carefully before using the tool.
SAFETYADVICE
• Please note safety instructions on Page 4-6.
• Always disconnect the air line before making any changes to the set-
tings or carrying out maintenance.
• Keepwater andair linesclearfromworkingrange ofthe machine. These
linesshould always lead away fromyouand behind the operatingarea.
• Before use, check the machine, hose and ttings for any damage or
material fatigue, only authorized service agents should carry out repairs.
• Always wear safety glasses and respiratory protection when working
with this machine. It is further recommended to wear safety gloves,
apron, as well as sturdy non-slipping shoes.
• Only use saw blades whose permitted speed is at least as high as the
highest no-load speed of the machine.
• Be sure saw blade ts the tool properly and securely. Do not modify the
tool to force t the blade. For example, do not remove blade guard.
• Check blades before use. The saw blade must be properly mounted
and turn freely. Perform a test run for at least 30 seconds without any
load. Do not use damaged, out of round or vibrating blades.
• Immediately switch o󰀨 the machine in case of considerable vibrations
or if other malfunctions occur. Check the machine in order to nd out
the cause.
• Always use and store the saw blades according to the manufacturer’s
instructions. The ange bolt must be tightened before starting to work
with the machine.
• The work piece must be secured if it is not heavy enough to prevent
movement.
• The tool is designed for cutting on horizontal surfaces.

10 PSG-125 5” PNEUMATICANGLE GRINDER
AIR PRESSURE AND VOLUME
The recommended air pressure for this pneumatic angle grinder is 90 PSI.
The most important factor in running this angle grinder is the volume of
air being supplied to the angle grinder. The volume is the air consumption
needed to run this angle grinder at a constant speed under light downward
hand pressure. The volume is measured in CFM (cubic foot per minute (ft3/
min)). Alpha® recommends running the tool at the maximum ow volume
of 33 CFM to get the full 1.4 HP rating out of the angle grinder.
It is also very important to keep your air cool, dry, and clean, so look for
a compressor with a refrigerated dryer and high-e󰀩ciency lter built-in or
purchase a separate air dryer and lter unit rated for your compressor’s
CFM. (See page 12 for Alpha®Filter/Regulator Manifold System)
RUST PROTECTION (A rust inhibitor oil is used to protect the tool
from rusting when not in use)
PROPERCAREANDMAINTENANCEAREIMPORTANT FACTORSIN
PREVENTING THIS TOOL FROM RUSTING ON THE INSIDE WHEN
NOT IN USE.
At the end of each workday, place 4-5 drops of rust inhibitor oil (included
with each angle grinder) into the tool using the oil port. Depress the throttle
lever varying the speed from very low to half speed, for thirty seconds. This
will allow the oil to transition into the rotor assembly and coat the inside of
the tool.
CLEANING THE ROTOR ASSEMBLY
Over time, the rotor assembly can ll up with oil sludge, vane dust residue,
and contamination and will need to be cleaned. To accomplish this, remove
the mu󰀪er assembly from the tool to allow the waste to exit. You can hold a
paper towel over the exit port to reduce the sound level and catch the exiting
waste. Add 10 to 20 drops of oil to the oil port and run the tool varying the
speed from very slow to half speed, for two to three minutes to allow the
oil to process through the machine. Check the paper towel for exit waste,
continue until there is little to no exit waste.
Run the tool at its slowest speed. If the tool sounds like it is running with
a variation in speed, this is an indication that one of the vanes is still stick-
ing in the rotor. Repeat the process to see if this will correct the variation
in sound. If the problem continues, contact an authorized Alpha®Repair
Center for routine repair and maintenance.

11
PSG-125 5” PNEUMATICANGLE GRINDER
HOW TO ADD THE RUST INHIBITOR OIL
1. Disconnect the angle grinder from
your air supply.
2. Remove the screw using a screw
driver. (See Fig. 3)
3. Add 4-5 drops of the Rust
Inhibitor Oil into the oil port. (See
Fig. 4)
4. Reinstall the Oil screw.
5. Reconnect the pneumatic
angle grinder to your air supply.
6. Depress the throttle lever
varying the speed from very low
to half speed, for thirty seconds.
(See Fig. 5)
Replacement Rust Inhibitor Oil
can be purchased from Alpha®
Professional Tools (Part No. AIR-008).
Figure 3
Figure 4
Figure 5

12 PSG-125 5” PNEUMATICANGLE GRINDER
CAUTION!
Lubricating the pneumatic grinder before and during work is not needed.
Excessive oil will turn to a tar-like substance inside the tool, causing the
vanes to stick in the rotor and slow the tool down. This is the reason we
donotrecommend automatic oilers to be used with this anglegrinder. Old
or worn compressors, which emit oil through the air lines, can signicantly
shorten the life of the tool.
HELPFUL HINT:
• Air throttle lever should be pressed and released slowly to
allow the angle grinder to accelerate and decelerate during
all applications. Rapid acceleration and deceleration can
wear out the ball bearings prematurely.
HELPFUL HINT:
• Using a Filter Regulator System is Recommended
FILTER/REGULATOR SYSTEM
Having a Filter/Regulator (See Fig. 6)
helps prevent pressure drops when
using a large volume of air, so you
can set the pressure of the pneumatic
angle grinder to 90 PSI, while the main
system can run at 125 PSI. The F/R
unit will also remove any water from
the air supply while also ltering the air
of contamination down to ve microns.
By only using aluminum and brass after the F/R unit, you are eliminating
any rust and contamination from getting into the air tools.
Alpha®recommends the F/R Manifold 53 CFM for single use with the
PSG-125 (Part No.1030-0022). All F/R manifolds are available through
our distributor network, and via our website.
CONNECTING THE AIR SUPPLY
The air Inlet for this pneumatic angle grinder is 3/8” NPT. Using a 3/8” or
1/2” inner diameter hose is highly recommended when operating this tool.
HELPFUL HINT:
Use Hi-Flo couplers and plugs to obtain the maximum CFM through the
tool.
Figure 6

13
PSG-125 5” PNEUMATICANGLE GRINDER
SPINDLE SIZE
TheAlpha® PSG-125 Pneumatic Angle Grinder has a 5/8”-11 spindle thread.
Maintenance and Usage Tip:
• Do not leave the angle grinder submersed in water. This could
expose the inner moving parts to moisture, which will shorten
the life of the angle grinder.
• Excessive force or impact to the spindle may result in
premature failure of gears and/or bearings, which may not be
immediately evident.
SOUND LEVEL (HEARING PROTECTION MUST BE WORN)
To comply with OSHA Occupational Noise Exposure Standard Number
1926.52, this tool is equipped with an internal Silencer System. When the
tool is operated correctly at 90 PSI, the sound level emitted should be less
than 86.4 dBA. The internal Silencer System is also used to maintain a
constant back pressure inside the tool; this helps prevent it from exceeding
the recommended 12,000 RPM. The exhaust deector for this angle grinder
also helps to reduce the noise level by venting the exhaust air.
Figure 7
ATTACHING THE SAFETY GUARD
1. Attach the Safety Guard onto PSG-125
2. Tighten nuts and hex screws to secure the safety guard.

14 PSG-125 5” PNEUMATICANGLE GRINDER
Figure 8
Figure 9
MOUNTING DIAMOND WHEELS
OPTION 1
OPTION 2
Lock Nut
Lock Nut
Double Open-end Wrench (1” / 32mm)
When attaching a straight cutting blade on the PSG-125, use the Inner
Flange for Cutting (Schematic No. 75) along with the Lock Nut for Cutting
(SchematicNo. 76) which isincluded in the boxof the PSG-125. This Inner
Flange for cutting is thicker and will provide clearance for installation of the
straight cutting blade.
NOTE: Mounting of the straight cutting blade onto the PSG-125, follow
the procedure in (Figure 8 or Figure 9) as shown above.

15
PSG-125 5” PNEUMATICANGLE GRINDER
Figure 10
ATTACHING THE SIDE HANDLE
Attach the handle into one of the two appointed locations for the most
comfort and stability when operating this tool. (See Fig. 10)
Note: AHandle Bracket is included with the pneumatic grinder, attach
thehandlebracketontothe side hole location of thepneumaticgrinder
and secure it using the Spring Washer and Screw. Attach the side
handle into the Handle Bracket. The Handle Bracket will raise the
Side Handle allowing more clearance between the material and Side
Handle during cutting applications for more user comfort.
Washer & Seal Set
Screw (M12x16)
Handle Bracket
Side Handle
Side Handle

16 PSG-125 5” PNEUMATICANGLE GRINDER
EXHAUST VENT
The exhaust vent
cover can be rotated
180 degrees to divert
the air flow coming
out of the Pneumatic
Angle Grinder.
OPERATION
THROTTLE OPERATION
Pressthe safety bar forwardtounlock the spring mechanism.Grip the body
in a way that the throttle lever is depressed to activate the motor. Releasing
the throttle lever shuts down the motor.
Figure 11
Figure 12

17
PSG-125 5” PNEUMATICANGLE GRINDER
Exhaust Port
WET CUTTING WITH THE ALPHA® PSG-125
The Alpha®Wet Blade Cutting Kit (WBC6KIT) is used for wet cutting and
grinding applications. See below for the recommended usage.
CAUTION!
NOTE: When using the PSG-125 for wet cutting and grinding, point
the spray nozzle away from the spindle shaft and tool and down
towards the cutting area as shown in Figure 13 & 14.
CAUTION!
NOTE: When the tool is being used wet, ice can form in and around
the exhaust port.
When cutting or grinding is nished,
move the tool away from the splash
area and store with the exhaust port
facing down to drain and prevent
any water from getting into the tool
through the exhaust port.
See Figure 15.
Figure 13 Figure 14
Figure 15

18 PSG-125 5” PNEUMATICANGLE GRINDER
ALPHA®PSG-125 5” PNEUMATIC ANGLE GRINDER
SCHEMATIC

19
PSG-125 5” PNEUMATICANGLE GRINDER
ALPHA®PSG-125 5” PNEUMATIC ANGLE GRINDER
PARTS LIST
DRAWING NO. PART NO. DESCRIPTION QUANTITY
13002-0001 5” Safety Guard 1
23002-0002 Retainer 1
33002-0003 Nut (M6) 2
43002-0004 Screw (M6x20) 2
53002-0005 Lock Nut 5/8”-11 for Grinding 1
63002-0006 Inner Flange for Grinding 1
73002-0007 Spacer Nut 1
83002-0008 Lock Nut 1
93002-0009 Felt Ring 1
10 3002-0010 Ball Bearing (6003LLU) 1
11 3002-0011 Spindle (5/8”-11) 1
12 3002-0012 Bevel Gear 1
13 3002-0013 Ball Bearing (606ZZ) 1
14 3002-0014 Bearing Holder 1
15 3002-0015 Oil Felt 1
16 3002-0016 Lubricator 1
17 3002-0017 Housing 1
18 3002-0018 Washer & Seal M12 (2pc set) 2
19 3002-0019 Screw (M12x3T/ 8.8L) 1
20 3002-0020 Retaining Ring (STW-9) 1
21 3002-0021 Bevel Pinion Gear 1
22 3002-0022 O-Ring (21.5x1.5) 1
23 3002-0023 Ball Bearing (6000LLU) 1
24 3002-0024 Front End Plate 1
25 3002-0025 Spring Pin (2.5x5) 2
26 3002-0026 Cylinder 1
27 3002-0027 Vane (4 pc Set) 1
28 3002-0028 Key (3x8L) 1
29 3002-0029 Rotor 1
30 3002-0030 End Plate 1
31 3002-0031 Ball Bearing (609ZZ) 1

20 PSG-125 5” PNEUMATICANGLE GRINDER
ALPHA®PSG-125 5” PNEUMATIC ANGLE GRINDER
PARTS LIST (CONT’D)
DRAWING NO. PART NO. DESCRIPTION QUANTITY
32 3002-0032 GovernorAssembly 1
33 3002-0033 Inlet Guide 1
34 3002-0034 O-Ring (28.5x2) 1
35 3002-0035 Nut 1
36 3002-0036 Rear Body 1
37 3002-0037 O-Ring (19.8x2.4) 1
38 3001-0074 Air Inlet (3/8”-18NPSM) 1
39 3002-0039 Screw 1
40 3002-0040 O-Ring (3.5x1.5) 1
41 3002-0041 Throttle Lever 1
42 3001-0072 Spring Pin (3x20L) 1
43 3002-0043 Pin 1
44 3001-0069 Spring 1
45 3001-0068 Safety Bar 1
46 3002-0046 Spring 1
47 3002-0047 Nylon Ball 1
48 3002-0048 O-Ring (13.5x1.5) 1
49 3002-0049 Bushing 1
50 3002-0050 O-Ring (15.5x1.5) 1
51 3002-0051 Retaining Ring (RTW-20) 1
52 3002-0052 Valve Pin (4x22.8) 1
53 3002-0053 O-Ring (27x2) 1
54 3002-0054 Mufer 1
55 3002-0055 Exhaust Vent 1
56 3002-0056 Spring 1
57 3002-0057 Exhaust Cover 1
58 3002-0058 Spacer Screw with Standoff 1
59 3002-0059 Washer (5.3x10x0.3) 1
60 3002-0060 Screw (M5x8L) 1
61 3002-0065 Side HandleAssembly 1
62 3002-0062 Pin Wrench (P:32mm) 1