MasterCraft 058-9325-8 User manual

INSTRUCTION MANUAL
AIR-POWERED
DUAL-ACTION SANDER
058-9325-8

TABLE OF CONTENTS
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AIR-POWERED DUAL-ACTION SANDER 058-9325-8
QUICK START GUIDE
TECHNICAL SPECIFICATIONS 3
SAFETY GUIDELINES 4–9
KEY PARTS DIAGRAM 10
IMPORTANT INFORMATION 11–13
OPERATING INSTRUCTIONS 14–16
MAINTENANCE 17–18
TROUBLESHOOTING 19-20
EXPLODED VIEW 21
PARTS LIST 22
WARRANTY 23–24

SAFETY GUIDELINES
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AIR-POWERED DUAL-ACTION SANDER 058-9325-8
This manual contains information that relates to PROTECTING PERSONAL SAFETY and PREVENTING
EQUIPMENT PROBLEMS. It is very important to read this manual carefully and understand it
thoroughly before using the product. The symbols listed below are used to indicate this information.
Note– The word “Note” is used to inform the
reader of something he/she needs to know about
the tool.
PERSONAL SAFETY
These precautions are intended for the personal safety of the user and others working with the user.
Please take time to read and understand them.
DANGER!
Potential hazard that will result in serious
injury or loss of life.
WARNING!
Potential hazard that could result in
serious injury or loss of life.
CAUTION!
Potential hazard that may result in
moderate injury or damage to equipment.

SAFETY GUIDELINES
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AIR-POWERED DUAL-ACTION SANDER 058-9325-8
SAFETY GUIDELINES
DANGER!
Potential hazard that will result in serious injury or loss of life.
•Keep children away from the work area. Do not allow children to handle
power tools.
•Do not use this tool in the presence of flammable liquids or gases. Sparks
that are created during use may ignite gases.
•Do not point the tool towards yourself or other people, even if the tool has
stopped. Keep hands, feet, and all other parts of the body away from work
area.
•Always ensure that the tool has stopped before putting it down after use, for
safety purpose and to prevent possible damage to the tool/user.
•Risk of electric shock: Do not expose the compressor to rain. Store it
indoors. Disconnect the compressor from the power source before servicing.
The compressor must be grounded. Do not use grounding adaptors.
•Risk of personal injury: Do not direct compressed air from the air hose
towards the user or other people.
•Risk for breathing: Never directly inhale the air produced by a compressor.
•Risk of bursting: Do not adjust the pressure switch or safety valve for any
reason. They have been preset at the factory for this compressor’s
maximum pressure. Tampering with the pressure switch or the safety valve
may cause personal injury or property damage.

SAFETY GUIDELINES
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AIR-POWERED DUAL-ACTION SANDER 058-9325-8
•Risk of burns: The pump and the manifold generate high temperatures. In
order to avoid burns or other injuries, do not touch the pump, the manifold,
or the transfer tube while the compressor is running. Allow the parts to cool
down before handling or servicing. Keep children away from the compressor
at all times.
•Do not use oxygen or any other combustible or bottled
gas to power air-powered tools. Failure to observe this
warning can cause explosion and serious personal injury
or death. Use only the compressed air to power the air-
powered tools. Use a minimum of 25' (7.6 m) of hose to
connect the tool to the compressor. Failure to comply will
result in serious injury or loss of life.
•Risk of bursting: Make sure the regulator is adjusted so
that the compressor outlet pressure is set lower than the
maximum operating pressure of the tool. Before starting
the compressor, pull the ring on the safety valve to make
sure the valve moves freely. Drain water from tank after
each use. Do not weld or repair tank. Relieve all pressure
in the hose before removing or attaching accessories.
Oxygen
Hydrogen
Explosive
Combustible
MC-OM-02
MC-OM-22

SAFETY GUIDELINES
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AIR-POWERED DUAL-ACTION SANDER 058-9325-8
WARNING!
Potential hazard that could result in serious injury or loss of life.
•Do not allow unskilled or untrained individuals to operate this tool.
•Always ensure that the accessories are specially designed for use with the
tool. Also ensure they are secured and correctly fastened before connecting
the tool to air supply.
•Switch and controls: Ensure that the air flow adjuster is closed when placing
the Air Sander in upside-down position, in order to avoid any personal injury.
•Do not carry the tool by the air supply hose.
•Pull the pressure safety valve ring every day in order to ensure that the
valve is functioning properly.
•Locate the compressor in a well-ventilated area for cooling, and must be a
minimum of 12" (31 cm) away from the nearest wall.
•Protect the air hose and the power cord from damage and puncture. Inspect
them for weak or worn spots every week, and replace them if necessary.
•Always wear hearing protection when using an air compressor. Failure to do
so may result in hearing loss.
•Do not carry the compressor while it is running.
•Do not operate the compressor if it is not in a stable position.
•Do not operate the compressor on a rooftop or in an elevated position that
could allow the unit to fall or be tipped over.

SAFETY GUIDELINES
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AIR-POWERED DUAL-ACTION SANDER 058-9325-8
CAUTION!
Potential hazard that may result in moderate injury or damage to
equipment.
•Always ensure that the tool has stopped before connecting to air supply.
•Do not wear watches, rings, bracelets, or loose clothing when using any air
tool.
•Keep proper footing at all times in order to ensure correct balance. verify
that the floor is not slippery, and wear non-slip shoes.
•Do not overload the tool. Allow the tool to operate at its optimum speed for
maximum efficiency.
• Do not use a tool that is leaking air, with missing or damaged parts, or that
requires repairs. Verify that all screws are securely tightened.
• For optimal safety and tool performance, inspect the tool daily in order to
ensure free movement of the trigger, safety mechanisms, and spring.
•Always keep your air-powered tool clean and lubricated. Daily lubrication is
essential to avoid internal corrosion and possible failures.
•Keep the workarea clean. A cluttered or dirty workbench may lead to an
accident. Floors should be kept clear.
•Use the tool only in a well-ventilated area.
•Handling and storage of oil: Use with adequate ventilation. Avoid contact of
oil with eyes, skin, and clothing. Avoid breathing spray or mist. Store in a
tightly closed container in a cool, dry, well-ventilated area free from
incompatible substances.
•Do not use the tool near or below the freezing condition, because the
moisture in the air line may freeze and prevent the tool operation.
•Do not store the tool in a freezing environment to prevent frost or ice
formation on the operating valves and mechanisms of the tool that may
cause tool failure.
•Do not use the tool for a taskthat it is not designed to perform.

IMPORTANT INFORMATION
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AIR-POWERED DUAL-ACTION SANDER 058-9325-8
General usage description
The Mastercraft®Air-powered Dual-action Sander features a housing made of durable, lightweight
aluminum. The tool is designed with comfortable and ergonomic grips. An air regulator is attached
for speed control, and a dust-proof mat is attached for filtering the debris away from the tool. The tool
is useful for sanding wood, metal, fiberglass, and auto body filler. This sander provides a quiet
sanding action for a smooth pattern-free finish.
Compatible compressor and air tool
GUIDELINES FOR PROPER USAGE AND OPERATION
Always ensure the use of appropriately matched air tools and compressors. The compressor should
be able to supply a minimal air delivery of 2.8 SCFM @ 90 PSI to ensure the compressor can run
continuously with the Mastercraft Air-powered Dual-action Sander. Using tools or a combination of
tools that together or separately require more than the air compressor can deliver will reduce
performance and could void the compressor or tool guarantee/warranty.
Air system
• Always use clean, dry, regulated, compressed air at 4 to 7 bar (60 to 100 PSI).
• Do not exceed the maximum and minimum pressures. Operating the tool at the wrong
pressure (too low or too high) will cause excessive noise or rapid wear.
Air Compressor
Size & Power 2 HP 2 1/2 HP 3+ HP
6 Gallons Light duty and
intermittent use
Light duty and
intermittent use
Medium duty and
intermittent use
8–11 Gallons Light duty and
intermittent use
Medium duty and
intermittent use
Heavy duty and
continuous use
15+ Gallons Medium duty and
intermittent use
Heavy duty and
continuous use
Heavy duty and
continuous use

IMPORTANT INFORMATION
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AIR-POWERED DUAL-ACTION SANDER 058-9325-8
Read this instruction manual thoroughly or have tool operators read thoroughly before using the tool.
• Read all safety guidelines
(see section “Safety guidelines”) at the beginning of this manual.
• Always inspect the air tool prior to each use to
– Ensure proper use of power source.
– Determine whether the tool is in proper working order.
• Use sanding pads which are specifically designed for this tool.
(see section “Technical
specifications”)
.
• Drain the compressor tank daily. Water in the air line will damage the tool.
• Clean the air inlet and the filter weekly.
• Line pressure should be increased to compensate for unusually long air hoses (over 8 meters).
The hose diameter should be 3/8" I.D.
CAUTION!
Potential hazard that may result in moderate injury or damage to
equipment.
•Verify that all connections in the air supply system are sealed in order to
prevent air from leaking. Failure to comply may result in moderate injury or
damage to equipment.
WARNING!
Potential hazard that could result in serious injury or loss of life.
• Do not use the tool if it is not in proper working order.
• Do not use oxygen or any other combustible or bottled gas to power this tool.
• Do not use this tool in the presence of any flammable liquids or gases.
• Keep hose away from heat, oil, and sharp edges. Check hose for wear and
tear, and ensure that all connections are secure. Failure to comply could lead to
serious injury or loss of life.

MAINTENANCE
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AIR-POWERED DUAL-ACTION SANDER 058-9325-8
• Air-operated tools must be inspected periodically, and worn or broken parts must be replaced
in order to keep tools operating safely, and efficiently.
• Inspect and replace worn or damaged O-rings, seals, etc. Tighten all screws and caps
frequently in order to help prevent personal injury.
• Inspect the trigger, the spring and the safety mechanism for free movement on a regular basis
in order to ensure that the safety system is fully functional.
• Verify that no part is loose or missing and that no part is stuck or jammed.
• Check the air supply for correct size and type of hose connectors. To avoid loss of power or
erratic action, ensure that there is no additional drain on the air line and no moisture or
restriction in the air pipe.
• Clean the air strainer (if provided in your model) in the air inlet region of the tool and remove
grit or gum deposits which may lead to loss of power or erratic action and may also reduce
the performance of the tool.
Storage
If it is necessary to store the tool for an extended period of time, apply a generous amount of
lubricating oil before storing. The tool should be allowed to run for approximately 30 seconds after
lubricating, in order to ensure that the lubrication is uniformly distributed throughout the tool.
• When the tool is not in use, disconnect it from the air supply, clean, and store it in a safe, dry,
and childproof location.
• When temperatures are below freezing, keep tools as warm as possible using any safe,
convenient method.
WARNING!
Potential hazard that could result in serious injury or loss of life.
• Never use damaged/worn sanding pads. Failure to comply could lead to
serious injury or loss of life.
CAUTION!
Potential hazard that may result in moderate injury or damage to
equipment.
• The tool should be stored in a clean and dry environment. Failure to comply
may result in moderate injury or damage to equipment.

TROUBLESHOOTING
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AIR-POWERED DUAL-ACTION SANDER 058-9325-8
Troubleshooting
The following chart lists common issues and solutions. Please read it carefully and follow all
instructions closely.
• Disconnect the tool from the air supply before making any adjustments.
• Repairs must be performed by a qualified service technician only.
WARNING!
Potential hazard that could result in serious injury or loss of life.
•If any of the following symptoms appears while the tool is in use, turn it off and
disconnect it from the air supply immediately. Failure to heed this warning will
result in serious personal injury.
PROBLEM POSSIBLE CAUSES SOLUTIONS
Tool runs at normal
speed but loses
power under load.
1. Motor parts are worn or
damaged.
2. Cam clutch is worn or stuck due
to lack of lubricant.
1. Lubricate the clutch housing.
2. Check for excess clutch oil. Clutch cases
should only be half filled, as overfilling can
cause drag on high speed clutch parts. A
typical oiled/lubricated wrench requires ½ oz
of oil.
Grease lubrication:
Heat is generated due to insufficient grease in
the cylinder. Severe operating conditions may
require frequent lubrication.
If the problem persists, call 1-800-689-9928.
Tool runs at low
speed. Air flows
slightly from exhaust.
1. Motor parts are jammed with dirt.
2. Power regulator is in closed
position.
3. Air flow is blocked by dirt.
1. Check whether there is blockage in the air
inlet and the filter.
2. Pour lubricating oil into air inlet as per
instructions.
3. Operate the tool by reversing rotation of the
tool back and forth in short duration. Repeat
the above steps as needed.

TROUBLESHOOTING
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AIR-POWERED DUAL-ACTION SANDER 058-9325-8
Note: For further repair information, please call 1-800-689-9928.
Tool stops working.
Air flows freely from
exhaust.
One or more motor vanes got stuck
due to material build up.
1. Pour lubricating oil into the air inlet.
2. Tap motor housing gently with plastic mallet.
3. Operate the tool by reversing rotation of the
tool back and forth in short duration. Repeat
the above steps as needed.
4. Disconnect the air supply. Operate the motor
by manually rotating the drive shank.
(wherever applicable) .
If the problem persists, call 1-800-689-9928.
Tool does not shut
off.
Throttle valve O-rings are dislodged
from seat inlet valve.
Replace O-rings.
If the problem persists, call 1-800-689-9928.
PROBLEM POSSIBLE CAUSES SOLUTIONS