National 3425 Instruction Manual

#3425 GRINDER/EDGER

INSTRUCTION MANUAL

Read Manual Before Operating Machine

9250 XYLON AVENUE NORTH • MINNEAPOLIS, MN 55445 • U.S.A.
800-245-0267 • 763-535-8206 • FAX [phone] • FAX [phone]
WEB SITE: www.nationalequipment.com • E-MAIL: [e-mail]

National

Flooring Equipment, Inc.

Page 2

TABLE OF CONTENTS

 Table of Contents ........................................................................................................2

 Rules for Safe Operation ........................................................................................3-6

A. Grounding ............................................................................................................5

B. Extension Cords ..................................................................................................6

 Transportation..............................................................................................................7

 Set-Up ........................................................................................................................8

A. Handle Assembly ................................................................................................8

 Running Machine ........................................................................................................9

A. Machine Start Up Procedure................................................................................9

 Procedure ............................................................................................................10-17

A. Grinder Mode ....................................................................................................10

B. Edger Mode........................................................................................................10

C. Plate or Cup Wheel Attachment ........................................................................11

D. Plate Removal....................................................................................................12

E. Shroud ........................................................................................................12-13

F. Wheel Adjustment ........................................................................................14-15

G. Handle ................................................................................................................15

H. Belt ....................................................................................................................16

I. Pulley Change Out ............................................................................................16

J. Vacuum Port ......................................................................................................17

K. Motor and Overload Switch................................................................................17

 Maintenance ........................................................................................................18-19

A. Maintaining Tools................................................................................................18

B. Cleaning ............................................................................................................19

C. Repairs ..............................................................................................................19

 Troubleshooting ........................................................................................................20

 Complete Parts List..............................................................................................21-22

 Part Numbers and Diagrams ..............................................................................23-30

 Labels ........................................................................................................................31

 Guarantee..................................................................................................................32

 Return Sheet ................................................................................................................

Page 3

RULES FOR SAFE OPERATION

READ AND SAVE ALL INSTRUCTIONS FOR FUTURE USE. Before use, be sure everyone operating this
equipment reads and understands this manual as well as any labels packaged with or attached to
the tool.

1. KNOW YOUR EQUIPMENT: Read this manual carefully to learn equipment applications and
limitations as well as potential hazards associated with this type of equipment.

2. GROUND YOUR TOOL: See Grounding.

3. AVOID DANGEROUS ENVIRONMENTS: Do not use in rain, damp or wet locations, or in the

presence of explosive atmospheres (gaseous fumes, dust or flammable materials). Remove materials
or debris that may be ignited by sparks.

4. KEEP WORK AREA CLEAN AND WELL LIT: Cluttered, dark work areas invite accidents.

5. DO NOT USE ON STEPS:

6. DRESS PROPERLY: Do not wear loose clothing. These may be caught in moving parts. When

working outdoors, wear rubber gloves and insulated non-skid footwear. Keep hands and gloves away
from moving parts.

7. USE SAFETY EQUIPMENT: Everyone in the work area should wear safety goggles or glasses
complying with current safety standards. Wear hearing protection during extended use and a dust
mask for dusty operations. Hard hats, face shields, safety shoes, etc. should be worn when specified
or necessary.

8. KEEP BYSTANDERS AWAY: Children and bystanders should be kept at a safe distance from the
work area to avoid distracting the operator and contacting the tool or extension cord. Operator should
be aware of who is around them and their proximity.

9. PROTECT OTHERS IN THE WORK AREA: Provide barriers or shields as needed to protect others
from debris.

10. USE PROPER ACCESSORIES: Using accessories that are not recommended may be hazardous.
Be sure accessories are properly installed and maintained. Do not delete a guard or other safety
device when installing an accessory or attachment.

11. CHECK FOR DAMAGED PARTS: Inspect guards and other parts before use. Check for
misalignment, binding of moving parts, improper mounting, broken parts and any other conditions that
may affect operation. If abnormal noise or vibration occurs, turn the tool off immediately and have the
problem corrected before further use. Do not use damaged equipment. Tag damaged tools “DO NOT
USE” until repaired. A guard or other damaged parts should be properly repaired or replaced. For all
repairs, insist on only identical National replacement parts.

12. REMOVE ALL ADJUSTING KEYS AND WRENCHES: Make a habit of checking that the adjusting
keys, wrenches, etc. are removed from the tool before turning it on.

13. GUARD AGAINST ELECTRIC SHOCK: Prevent body contact with grounded surfaces such as pipes,
radiators, ranges and refrigerators. Before use always check the work area for hidden wires or pipes.
Use a Ground Fault Circuit Interrupter (GFCI) to reduce shock hazards.

14. AVOID ACCIDENTAL STARTING: Be sure equipment is turned off before plugging it in. Do not use a
tool if the power switch does not turn the tool on and off.

15. DO NOT FORCE EQUIPMENT: Equipment will perform best at the rate for which it was designed.
Excessive force only causes operator fatigue, increased wear and reduced control.

16. KEEP HANDS AWAY FROM ALL CUTTING EDGES AND MOVING PARTS.

17. WEAR GLOVES WHEN CHANGING PLATES.

18. DO NOT ABUSE CORD: Never unplug by yanking the cord from the outlet. Pull plug rather than cord

to reduce the risk of damage. Keep the cord away from heat, oil, sharp objects, cutting edges and
moving parts.

Page 4

RULES FOR SAFE OPERATION

19. DO NOT OVERREACH. MAINTAIN CONTROL: Keep proper footing and balance at all times.

Maintain a firm grip.

20. STAY ALERT: Watch what you are doing, and use common sense. Do not use when you are tired,
distracted or under the influence of drugs, alcohol or any medication causing decreased control.

21. STARTING MACHINE: On/off switch must be in off position before connecting to power source.

22. DO NOT DEFEAT OR ALTER A SWITCH OR SAFETY DEVICE:

23. UNPLUG EQUIPMENT: When it is not in use, unplug tool before changing accessories or performing

recommended maintenance.

24. MAINTAIN EQUIPMENT CAREFULLY: Keep handles dry, clean and free from oil and grease. Follow
instructions for lubricating and changing accessories. Periodically inspect tool cords and extension
cords for damage. Have damaged parts repaired or replaced.

25. STORE IDLE EQUIPMENT: When not in use, store in a dry, secured place. Keep away
from children.

26. MAINTAIN LABELS AND NAMEPLATES: These carry important information. If unreadable or
missing, contact National for a free replacement.

26. MACHINE IS HEAVY, DO NOT DROP:

WARNING: Exposure to dust may cause respiratory ailments. Use approved NIOSH or OSHA

respirators, safety glasses or face shields, gloves and protective clothing. Provide adequate ventilation
to eliminate dust, or to maintain dust level below the Threshold Limit Value for nuisance dust as
classified by OSHA.

WARNING: Always wear respirator protection, appropriate for the application, as specified by
OSHA regulations and your employer. Never operate or maintain equipment before reading and
understanding the instructions for operation and maintenance. Obey all safety signs and instructions
while operating or maintaining equipment.

WARNING: Failure to follow any of the above instructions could cause damage to machine,

damage to property or serious bodily injury or death.

WARNING: SILICA DUST WARNING

Grinding/cutting/drilling of masonry, concrete, metal and other materials can
generate dust, mists and fumes containing chemicals known to cause serious fatal
injury or illness, such as respiratory disease, cancer, birth defects or other
reproductive harm. If you are familiar with the risks associated with the particular
material being cut, review the material safety data sheet and/or consult you

employer, the material manufacturer/supplier, governmental agencies such as
OSHA and NIOSH and other sources of hazardous materials. California and some other other
authorities, for instance, have published lists of substances known to cause cancer, reproductive
toxicity, or other harmful effects. Control dust, mist and fumes at the source where possible. In this
regard use good work practices and follow the recommendations of the manufacturer/supplier,
OSHA/NIOSH, and occupational and trade associations. When the hazards from inhalation of dust,
mists and fumes cannot be eliminated, the operator and any bystanders should always wear a
respirator approved by OSHA/MSHA for the material being cut.

Page 5

RULES FOR SAFE OPERATION

GROUNDED TOOLS: TOOLS WITH THREE PRONG PLUGS

Tools marked “Grounding Required” have a three wire cord and three prong grounding plug. The plug
must be connected to a properly grounded outlet (See Figure A). If the tool should electrically malfunction
or break down, grounding provides a low resistance path to carry electricity away from the user, reducing
the risk of electric shock.

The grounding prong in the plug is connected through the green wire inside the cord to the grounding
system in the tool. The green wire in the cord must be the only wire connected to the tool's grounding
system and must never be attached to an electrically “live” terminal.

Your tool must be plugged into an appropriate outlet, properly installed and grounded in accordance with
all codes and ordinances. The plug and outlet should look like those in Figure A.

Figure B illustrates a temporary adapter available for connecting grounded plugs (Figure A) to two prong
outlets. The green rigid ear or lug extending from the adapter must be connected to a permanent ground
such as a properly grounded outlet box or receptacle. Simply remove the center screw from the outlet,
insert the adapter and reattach the screw through the green grounding ear to the outlet. If in doubt of
proper grounding, call a qualified electrician. A temporary adapter should only be used until a properly
grounded outlet can be installed by a qualified electrician. The Canadian Electrical Code prohibits the use
of temporary adapters.

Figure A

2

1

3

6

GROUNDING

1. Cover of grounded outlet box

2. Outlet ground

3. Grounding prong

4. Temporary adapter

5. Screw

6. Green grounding ear

4

5

Figure B

WARNING: Electrical cords can be hazardous. Misuse can result in fire or death by electrical

shock. Read carefully and follow all directions.

WARNING: Improperly connecting the grounding wire can result in the risk of electric shock.
Check with a qualified electrician if you are in doubt as to whether the outlet is properly grounded. Do
not modify the plug provided with the tool. Never remove the grounding prong from the plug. Do not
use the tool if the cord or plug is damaged. If the plug will not fit the outlet, have a proper outlet
installed by a qualified electrician.

CAUTION: Recommended use of GFI receptical.

Page 6

RULES FOR SAFE OPERATION

EXTENSION CORDS

Grounded tools require a three wire extension cord. Double insulated tools can use either a two or three
wire extension cord. As the distance from the supply outlet increases, you must use a heavier gauge
extension cord. Using extension cords with inadequately sized wire causes a serious drop in voltage,
resulting in loss of power and possible tool damage.

The smaller the gauge number of the wire, the greater the capacity of the cord. For example, a 14 gauge
cord can carry a higher current than a 16 gauge cord. When using more than one extension cord to make
up the total length, be sure each cord contains at least the minimum wire size required. If you are using
one extension cord for more than one tool, add the nameplate amperes and use the sum to determine the
required minimum wire size.

GUIDELINES FOR USING EXTENSION CORDS

• If you are using an extension cord outdoors, make sure it is marked with the suffix “W-A” (“W” in
Canada) to indicate that it is acceptable for outdoor use.

• Be sure your extension cord is properly wired and in good electrical condition. Always replace a
damaged extension cord or have it repaired by a qualified person before using it.

• Protect your extension cords from sharp objects, excessive heat and damp or wet areas.

• Keep away from water. Do not use if wet.

• Inspect thoroughly before each use. DO NOT USE IF DAMAGED.

• Make sure equipment is OFF before connecting cord outlet.

• FULLY INSERT plug into outlet.

• Do not remove, bend or modify any metal prongs or pins of cord.

• Do not use excessive force to make connections.

• Do not connect a three prong plug to a two-hole cord.

• Avoid overheating. Uncoil cord and do not cover it with any material.

• Do not walk on cord.

• Do not drive, drag or place objects over cord.

READ AND SAVE ALL INSTRUCTIONS FOR FUTURE REFERENCE.

WARNING: Electrical cords can be hazardous. Misuse can result in fire or death by electrical

shock. Read carefully and follow all directions.

Page 7

LOAD AND UNLOAD

• Remove plate before loading or unloading.

• Always disconnect from power source before transporting.

• Loosening Handle Securing “T” Bolts to slide handle down to make machine easier to load. Retighten
“T” Bolts when handle is at the desired height.

• Disconnecting handle cord from the motor plug cord and the handle can be removed to make machine
more compact.

TRANSPORTATION

Page 8

HANDLE ASSEMBLY

Handle allows for 7-1/2" of adjustment depending on operator height. Insert handle (See Figure 1) to
desired length and properly tighten both locking "T" bolts (See Figure 2). Plug handle cord into motor
cord (See Figure 3). Make sure both “T” Bolts engage handle at all times.

SET-UP

WARNING: Handle must be engaged with both securing "T" bolts. Failure to do so could cause

serious injury.

Figure 2

Figure 3

Figure 1

Securing

T-Bolts

Handle

Cord

Motor

Cord

Page 9

MACHINE START UP PROCEDURE

TO RUN MACHINE

1. Machine MUST be off before plugging machine into power source.

2. Plug power cord into proper size extension cord.

3. Plug power cord into outlet.

4. Plug the motor cord plug into the handle cord plug if not connected.

5. Press down on handle slightly tilting machine back, lifting the grinding disk (disengaging) off from
the floor.

6. Depress lever on handle, motor will run.

7. Release lever for motor to stop.

8. Once machine is running, gently lower disk to the floor.

RUNNING MACHINE

WARNING: DO NOT leave a plugged-in machine unattended.

Improper connection of the equipment-grounding conductor can result in a risk of electrical shock.
Check with a qualified electrician or service person if you are in doubt as to whether the outlet is
properly grounded. DO NOT modify the plug provided with this unit. If it will not fit the outlet, have a
proper outlet installed by a qualified electrician. NOTE: In Canada, the use of a temporary adapter is
not permitted by the Canadian Electrical Code.

Improper use of the grounding plug can result in a risk of electrical shock.

Know what you are removing. Scraping, sanding or grinding can release health hazardous dust and
liquids. Make sure you are following OSHA, State and/or Federal guidelines when removing hazardous
materials. Take necessary precautions and procedures. On some materials, grinding, scraping or
sanding are not allowed.

Figure 1

WARNING: DO NOT lock lever on handle into a permanent on position. If operator would lose

control or be disabled, machine continues to operate. Do not defeat a switch or safety device.

Shroud
securing screws

Shroud

securing screws

Page 10

GRINDER MODE (Figure 1)

Make sure plate or cup wheel is completely covered and not protruding out from the shroud. Shroud
should suck to the floor when vacuum is turned on. Do not have plate exposed when using the machine
in grinder mode. Failure to do so could cause severe bodily injury or property damage.

Wheels are independently adjustable in height, which allows for pressure to be applied at any point of the
plate or cup wheel. Refer to wheel adjustment in the manual for adjustment instructions.

EDGER MODE (Figure 2)

When using the machine as an edger, adjustments will need to be made to shroud, handle and the wheel
rotation. Refer to these sections in the manual for procedure instructions.

PROCEDURE

Figure 1

Figure 2