Ryobi Grinder AG400 User Guide

OPERATOR'S MANUAL  
4 in. (100 mm) Angle Grinder  
Model AG400 / Double Insulated  
SPECIFICATIONS:  
Grinding Wheel Capacity  
Rating  
4 in. (100 mm)  
120 volts, 60Hz, AC only  
11,000 RPM  
No Load Speed  
Amperes  
4.3 Amperes  
Net Weight  
4.0 lbs. (1.8 kg.)  
THANK YOU FOR BUYING A RYOBI ANGLE GRINDER.  
YournewanglegrinderhasbeenengineeredandmanufacturedtoRyobi'shighstandardfordependability, easeofoperation,  
and operator safety. Properly cared for, it will give you years of rugged, trouble-free performance.  
CAUTION: Carefully read through this entire operator's manual before using your new angle grinder.  
Pay close attention to the Rules for Safe Operation, Warnings, and Cautions. If you use your grinder properly and only for  
what it is intended, you will enjoy years of safe, reliable service.  
Please fill out and return the Warranty Registration Card so that we can be of future service to you.  
Thank you again for buying Ryobi tools.  
SAVE THIS MANUAL FOR FUTURE REFERENCE  
 
RULES FOR SAFE OPERATION  
The purpose of safety symbols is to attract your attention to possible dangers. The safety symbols, and the  
explanations with them, deserve your careful attention and understanding. The safety warnings do not by  
themselves eliminate any danger. The instructions or warnings they give are not substitutes for proper  
accident prevention measures.  
SYMBOL  
MEANING  
SAFETY ALERT SYMBOL:  
Indicates danger, warning, or caution. May be used in conjunction with other symbols or pictographs.  
DANGER: Failure to obey a safety warning will result in serious injury to yourself or to others. Always  
follow the safety precautions to reduce the risk of fire, electric shock and personal injury.  
WARNING:Failuretoobeyasafetywarningcanresultinseriousinjurytoyourselfortoothers.Always  
follow the safety precautions to reduce the risk of fire, electric shock and personal injury.  
CAUTION: Failure to obey a safety warning may result in property damage or personal injury to  
yourself or to others. Always follow the safety precautions to reduce the risk of fire, electric shock and  
personal injury.  
NOTE:  
Advises you of information or instructions vital to the operation or maintenance of the equipment.  
DOUBLE INSULATION  
IMPORTANT  
Your Ryobi power tool is double insulated. This means you  
areseparatedfromthetool'selectricalsystembytwocomplete  
sets of electrical insulation. This extra layer of insulation is  
intended to protect the user from electrical shock due to a  
break in the wiring insulation. All exposed metal parts are  
isolated from the internal metal motor components with  
protecting insulation. Double insulated tools do not need to  
be grounded.  
Servicing of a tool with double insulation requires extreme  
care and knowledge of the system and should be performed  
onlybyaqualifiedservicetechnician.Forservicewesuggest  
you return the tool to your nearest RYOBI AUTHORIZED  
SERVICE CENTER for repair. When servicing use only  
identical Ryobi replacement parts.  
WARNING:  
Do not attempt to operate this tool until you have read  
thoroughly and understand completely all instructions,  
safety rules, etc. contained in this manual. Failure to  
comply can result in accidents involving fire, electric  
shock, or serious personal injury. Save operator's manual  
and review frequently for continuing safe operation, and  
instructing others who may use this tool.  
WARNING:  
The double insulated system is intended to protect the  
user from shock resulting from a break in the tool's  
internal wiring. Observe all normal safety precautions  
related to avoiding electrical shock.  
WARNING:  
WEAR YOUR  
The operation of any angle grinder can result in foreign objects being thrown into your eyes,  
which can result in severe eye damage. Before beginning power tool operation, always wear  
safety goggles or safety glasses with side shields and a full face shield when needed. We  
recommend Wide Vision Safety Mask for use over eyeglasses or standard safety glasses with  
side shields. Always wear eye protection which is marked to comply with ANSI Z87.1.  
SAFETY GLASSES  
FORESIGHT IS BETTER  
THAN NO SIGHT  
Page 3  
 
RULES FOR SAFE OPERATION  
of inattention while operating power tools may result  
in serious personal injury.  
WARNING:  
Read and understand all instructions. Failure to  
follow all instructions listed below, may result in elec-  
tric shock, fire and/or serious personal injury.  
Dress properly. Do not wear loose clothing or  
jewelry. Contain long hair. Keep your hair, cloth-  
ing, and gloves away from moving parts. Loose  
clothes, jewelry, or long hair can be caught in moving  
parts.  
SAVE THESE INSTRUCTIONS  
Avoid accidental starting. Be sure switch is off be-  
fore plugging in. Carrying tools with your finger on  
the switch or plugging in tools that have the switch on  
invites accidents.  
Work Area  
Keep your work area clean and well lit. Cluttered  
benches and dark areas invite accidents.  
Do not operate power tools in explosive atmo-  
spheres, such as in the presence of flammable  
liquids, gases, or dust. Power tools create sparks  
which may ignite the dust or fumes.  
Remove adjusting keys or wrenches before turn-  
ing the tool on. A wrench or a key that is left at-  
tached to a rotating part of the tool may result in  
personal injury.  
Keep bystanders, children, and visitors away  
while operating a power tool. Distractions can  
cause you to lose control.  
Do not overreach. Keep proper footing and bal-  
ance at all times. Proper footing and balance en-  
ables better control of the tool in unexpected situa-  
tions.  
Electrical Safety  
Double insulated tools are equipped with a po-  
larized plug (one blade is wider than the other).  
This plug will fit in a polarized outlet only one  
way. If the plug does not fit fully in the outlet,  
reverse the plug. If it still does not fit, contact a  
qualified electrician to install a polarized outlet.  
Do not change the plug in any way. Double insu-  
Use safety equipment. Always wear eye protec-  
tion. Dust mask, non-skid safety shoes, hard hat, or  
hearing protection must be used for appropriate con-  
ditions.  
Tool Use and Care  
Use clamps or other practical way to secure and  
support the workpiece to a stable platform. Hold-  
ing the work by hand or against your body is un-  
stable and may lead to loss of control.  
lation  
eliminates the need for the three wire  
grounded power cord and grounded power supply  
system.  
Do not force tool. Use the correct tool for your  
application. The correct tool will do the job better  
and safer at the rate for which it is designed.  
Do not use tool if switch does not turn it on or  
off.Any tool that cannot be controlled with the switch  
is dangerous and must be repaired.  
Disconnect the plug from the power source be-  
fore making any adjustments, changing acces-  
sories, or storing the tool. Such preventive safety  
measures reduce risk of starting the tool acciden-  
tally.  
Store idle tools out of reach of children and other  
untrained persons. Tools are dangerous in the  
hands of untrained users.  
Maintain tools with care. Keep cutting tools sharp  
and clean. Properly maintained tools with sharp  
cutting edges are less likely to bind and are easier  
to control.  
Avoid body contact with grounded surfaces such  
as pipes, radiators, ranges and refrigerators.  
There is an increased risk of electric shock if your body  
is grounded.  
Don't expose power tools to rain or wet condi-  
tions. Water entering a power tool will increase the  
risk of electric shock.  
Do not abuse the cord. Never use the cord to  
carry the tools or pull the plug from an outlet.  
Keep cord away from heat, oil, sharp edges or  
moving parts. Replace damaged cords immedi-  
ately. Damaged cords increase the risk of electric  
shock.  
When operating a power tool outside, use an out-  
door extension cord marked “W-A” or “W”. These  
cords are rated for outdoor use and reduce the risk of  
electric shock.  
Personal Safety  
Check for misalignment or binding of moving  
parts, breakage of parts, and any other condi-  
tion that may affect the tool's operation. If dam-  
aged, have the tool serviced before using. Many  
accidents are caused by poorly maintained tools.  
Stay alert, watch what you are doing and use  
common sense when operating a power tool. Do  
not use tool while tired or under the influence of  
drugs, alcohol, or medication. A moment  
Page 4  
 
RULES FOR SAFE OPERATION  
Use only accessories that are recommended by the  
Dust and waste materials should not be allowed  
to build up in the workshop. Hot metal sparks could  
start a fire.  
manufacturer for your model. Accessories that may  
be suitable for one tool, may become hazardous when  
used on another tool.  
Do not enlarge or alter the center hole of the grinding  
wheel as this could result in breaking it.  
Service  
Use only the normal grinder surface. Never use the  
Tool service must be performed only by qualified  
repair personnel. Service or maintenance performed  
by unqualified personnel could result in a risk of injury.  
side or upper surfaces for cutting.  
Keep the tool and its handle dry, clean, and free  
from oil and grease. Always use a clean cloth when  
cleaning. Never use brake fluids, gasoline, petroleum-  
based products, or any strong solvents to clean your  
tool.  
When servicing a tool, use only identical replace-  
ment parts. Follow instructions in the Maintenance  
section of this manual. Use of unauthorized parts or  
failure to follow Maintenance Instructions may create  
a risk of electric shock or injury.  
Additional Rules for Safe Operation  
Know your power tool. Read operator's manual care-  
fully. Learn its applications and limitations as well as  
the specific potential hazards related to this tool. Fol-  
lowingthisrulewillreducetheriskofelectricshock,fire,  
or serious injury.  
Specific Safety Rules for Grinders  
Always use proper guard with grinding wheel. A  
guard protects operator from broken wheel fragments.  
Accessories must be rated for at least the speed  
recommended on the tool warning label. Wheels  
and other accessories running over rated speed can  
fly apart and cause injury.  
Hold tool by insulated gripping surfaces when per-  
forming an operation where the tool may contact  
hidden wiring or its own cord. Contact with a “live”  
wire will make exposed metal parts of the tool “live”  
and shock the operator.  
Always wear safety glasses with side shields. Ev-  
eryday eyeglasses have only impact resistant lenses;  
they are NOT safety glasses.  
Protect your lungs. Wear a face or dust mask if the  
operation is dusty.  
Protect your hearing. Wear hearing protection during  
extended periods of operation.  
Grinding wheel and guard must be securely  
attached as described in this operating manual before  
connecting the grinder to a power source.  
Inspect tool cords periodically and if damaged, have  
repaired at your nearest authorized service center. Stay  
constantly aware of cord location.  
Grinding wheels must be stored in a dry place.  
Before attaching the grinding wheel, inspect it for  
visible defects. If cracked, chipped, or warped, do not  
install it.  
Do not overtighten the clamp nut on the grinding  
wheel. Excessive tightening can cause the wheel to  
crack during operation  
Make sure that the guard is in good condition and  
securely installed before operating grinder.  
Do not clamp the grinder in a vise or use as a  
fixed grinder.  
Never turn on the grinder with the grinding wheel  
or any rotating parts touching the workpiece.  
Use only grinding wheels in compliance with ANSI  
standard B7.1 and rated greater than 11,000 RPM.  
Do not use the grinder if the disc flange or clamp  
nut is missing or if the spindle is bent.  
Always hold the grinder securely with two hands  
while working and at all times when it is running.  
Never cover the air vents in the motor housing  
with your hands while operating the grinder.  
Hold the tool away from your body while it is  
running. Keep your hands away from the abrasive  
attachments.  
Check damaged parts. Before further use of the tool,  
a guard or other part that is damaged should be  
carefully checked to determine that it will operate  
properly and perform its intended function. Check for  
alignment of moving parts, binding of moving parts,  
breakage of parts, mounting, and any other conditions  
that may affect its operation. A guard or other part that  
is damaged should be properly repaired or replaced by  
an authorized service center. Following this rule will  
reduce the risk of electric shock, fire, or serious injury.  
Do not abuse cord. Never carry tool by cord or yank  
it to disconnect from receptacle. Keep cord from  
heat, oil and sharp edges. Following this rule will  
reduce the risk of electric shock or fire.  
Make sure your extension cord is in good condi-  
tion. Whenusinganextensioncord, besuretouseone  
heavy enough to carry the current your product will  
draw. A wire gage size (A.W.G.) of at least 16 is  
recommended for an extension cord 100 feet or less in  
length. A cord exceeding 100 feet is not recommended.  
If in doubt, use the next heavier gage. The smaller the  
gage number, the heavier the cord. An undersized cord  
will cause a drop in line voltage resulting in loss of power  
and overheating.  
Page 5  
 
RULES FOR SAFE OPERATION  
Inspect for and remove all foreign objects from  
workpiece before grinding. Following this rule will  
reduce the risk of serious personal injury.  
WARNING:  
Some dust created by power sanding, sawing, grinding,  
drilling, and other construction activities contains  
chemicals known to cause cancer, birth defects or  
other reproductive harm. Some examples of these  
chemicals are:  
Drugs, Alcohol, Medication. Do not operate tool  
while under the influence of drugs, alcohol, or any  
medication. Following this rule will reduce the risk of  
electric shock, fire, or serious injury.  
Keep hands away from grinding area. Following this  
• lead from lead-based paints,  
• crystalline silica from bricks and cement and other  
masonry products, and  
• arsenic and chromium from chemically-treated  
lumber.  
rule will reduce the risk of serious personal injury.  
Save these instructions. Refer to them frequently  
and use them to instruct others who may use this tool.  
If you loan someone this tool, loan them these instruc-  
tions also.  
Your risk from these exposures varies, depending on  
how often you do this type of work. To reduce your  
exposure to these chemicals: work in a well ventilated  
area, and work with approved safety equipment, such  
as those dust masks that are specially designed to filter  
out microscopic particles.  
SAVE THESE INSTRUCTIONS  
SYMBOLS  
Important: Some of the following symbols may be used on your tool. Please study them and learn their meaning. Proper  
interpretation of these symbols will allow you to operate the tool better and safer.  
SYMBOL  
NAME  
DESIGNATION/EXPLANATION  
V
Volts  
Voltage  
A
Amperes  
Hertz  
Current  
Hz  
W
Frequency (cycles per second)  
Watt  
Power  
Time  
min  
Minutes  
Alternating Current  
No Load Speed  
Type or a characteristic of current  
Rotational speed, at no load  
n
0
Designates Double Insulated  
Construction tools  
Class II Construction  
Revolutions, strokes, surface speed,  
orbits etc. per minute  
.../min  
Revolutions or Reciprocation Per Minute  
Indicates danger, warning or caution.  
It means attention!!! Your safety is  
involved.  
Safety Alert Symbol  
Page 6  
 
ELECTRICAL  
EXTENSION CORDS  
ELECTRICAL CONNECTION  
When using a power tool at a considerable distance from the  
power source, use an extension cord heavy enough to carry  
the current that the tool will draw. An undersized extension  
cord will cause a drop in line voltage, resulting in a loss of  
power and causing the motor to overheat. Use the chart  
provided below to determine the minimum wire size required  
in an extension cord. Only round jacketed cords listed by  
Underwriter's Laboratories (UL) should be used.  
Your grinder has a precision built electric motor. It should be  
connected to a power supply that is 120 volts, 60Hz, AC  
only (normal household current). Do not operate this tool  
on direct current (DC). A substantial voltage drop will cause  
a loss of power and the motor will overheat. If your tool does  
not operate when plugged into an outlet, double check the  
power supply.  
Length of Extension Cord  
Wire Size (A.W.G.)  
CAUTION:  
Keep the cord away from the cutting area and position  
the cord so that it will not be caught on lumber, tools, or  
other objects during cutting.  
Up to 50  
51 to 100  
16  
14  
When working with the tool outdoors, use an extension cord  
that is designed for outside use. This is indicated by the  
letters WA on the cord's jacket.  
Before using an extension cord, inspect it for loose or  
exposed wires and cut or worn insulation.  
UNPACKING  
With the exception of the side handle and grinding wheel,  
youranglegrinderhasbeenshippedcompletelyassembled.  
PACKING LIST  
Angle Grinder With Guard  
Grinding Wheel  
Carefully remove the grinder and accessories from the  
box. Make sure that all items listed in the packing list are  
included.  
Side Handle  
Wrench  
Inspect grinder carefully to make sure no breakage or  
Operator's Manual  
Warranty Registration Card  
damage has occurred during shipping.  
If any parts are damaged or missing, contact your nearest  
Ryobi dealer to obtain replacement parts before  
attempting to operate grinder.  
WARNING:  
Do not discard the packing material until you have  
carefully inspected and satisfactorily operated grinder.  
If any parts are missing, do not operate your grinder until  
the missing parts are replaced. Failure to do so could  
result in possible serious personal injury.  
Page 7  
 
FEATURES  
KNOW YOUR ANGLE GRINDER  
Before attempting to use your grinder, familiarize yourself  
with all operating features and safety requirements.  
See Figure 1.  
Side Handle  
The side handle provided, stabilizes your grinder and must  
be used during all grinding operations. In addition to  
maintaining safe control during use, the side handle also  
provides convenient ease of operation for the operator.  
Makesureallgrindingwheels andrecommendedaccessories  
are in accordance with listed specifications for this tool. For  
example, do not use grinding wheels that are rated at less  
than 11,000 RPM.  
Spindle Lock Button  
The spindle lock button secures the spindle so that only one  
wrench is needed to change the grinding wheel.  
Guard  
A protective guard has been provided on your grinder. It  
deflects sparks and metal chips during use.  
Switch Button  
Your grinder has a conveniently located switch. It also has a  
lock-on feature that allows the grinder to be locked in the on  
position when continuous operation for extended periods of  
time is required.  
Heavy Duty Motor  
Your Ryobi AG400 Angle Grinder has a powerful motor, with  
sufficient power to handle tough grinding jobs that require  
heavy duty performance.  
APPLICATIONS  
(Use only for the purposes listed below)  
Grinding metals.  
Preparing surfaces to be welded.  
Grinding welds.  
SWITCH BUTTON  
SPINDLE  
LOCK BUTTON  
SIDE HANDLE  
WRENCH  
GUARD  
GRINDING WHEEL  
Fig. 1  
WARNING:  
Do not allow familiarity with your grinder to make you  
careless. Remember that a careless fraction of a second  
is sufficient to inflict severe injury.  
Page 8  
 
ASSEMBLY  
WARNING:  
Your grinder should never be connected to power supply  
when you are assembling parts, making adjustments,  
installingorremovinggrindingwheels,orwhennotinuse.  
Disconnectingyourgrinderwillpreventaccidentalstarting  
that could cause serious injury.  
GEAR  
HOUSING  
INSTALLING THE SIDE HANDLE  
See Figure 2.  
UNPLUG YOUR GRINDER.  
WARNING:  
Failure to unplug your grinder could result in accidental  
starting causing serious injury.  
SIDE  
HANDLE  
Fig. 2  
TO  
TIGHTEN  
Install the side handle by screwing it into the side of the  
WRENCH  
gear housing.  
Note: The handle can be installed on either the left or  
right side of the grinder, depending on operator prefer-  
ence. It must always be used to prevent loss of control  
and possible serious injury.  
TO  
LOOSEN  
CLAMP  
NUT  
Tighten side handle securely.  
GRINDING  
WHEEL  
INSTALLING THE GRINDING WHEEL  
See Figure 3.  
UNPLUG YOUR GRINDER.  
WARNING:  
Failure to unplug your grinder could result in accidental  
starting causing serious injury.  
DISC  
FLANGE  
SPINDLE  
Your grinder is shipped with the disc flange and clamp  
nut attached to the spindle.  
Depress spindle lock button and rotate clamp nut until  
spindle locks.  
Loosen and remove clamp nut from spindle. Do not  
remove disc flange.  
FLAT(S)  
Make sure flats on the bottom of disc flange are engaged  
with flats on spindle.  
SPINDLE  
LOCK BUTTON  
Place the grinding wheel over the spindle with the  
Fig. 3  
concave side of the wheel facing up.  
Thread the clamp nut on the spindle with the flat side of  
the nut facing up. Fit the raised, small diameter portion  
of the clamp nut into the hole in the grinding wheel and  
finger tighten.  
WARNING:  
Always install grinding wheel with the depressed center  
against the disc flange as shown in figure 3. Failure to do  
so will cause the grinding wheel to crack when tightening  
the clamp nut. This could result in serious personal injury  
because of loose particles breaking off and being thrown  
from the grinder. Never use a grinding wheel with a  
mounting hole larger than 5/8". Do not overtighten.  
Depress the spindle lock button and rotate the wheel  
clockwise until the spindle locks in position.  
Securely tighten the clamp nut with the wrench provided.  
Do not overtighten.  
Page 9  
 
ADJUSTMENTS  
A
WARNING:  
Before connecting your grinder to power supply, always  
check to be sure switch is not in lock-on position. Failure  
to do so could result in accidental starting of your grinder  
resulting in possible serious injury.  
GUARD LOCATION  
The guard on your grinder should be correctly installed  
depending on which side the handle is mounted. Never use  
yourgrinderwithouttheguardcorrectlyinplace. Figures  
4, 5, and 6 show correct and incorrect locations of the guard.  
CORRECT  
LOCATION OF GUARD IS  
BETWEEN POINTS A AND B  
Fig. 4  
WARNING:  
B
Never place the guard so that it is on front of the grinder as  
showninfigure6. Thiscouldresultinseriousinjurybecause  
sparks and loose particles thrown from the grinding wheel  
would be directed toward the operator. Always place the  
guard in the correct location as shown in figures 4 and 5.  
OPERATION  
WARNING:  
Always wear safety glasses and keep guard in place  
when grinding.  
Fig. 5  
Hot metal sparks from metal grinding can cause a fire.  
Avoid spark contact with flammable materials such as  
saw dust or clothing.  
INCORRECT  
LOCATION OF GUARD  
Grinding wheels must be free of fissures and cracks.  
Fissures and cracks can cause a grinding wheel to  
shatter resulting in possible serious injury.  
Thoroughly inspect a new grinding wheel before it is  
installed on the grinder.  
1. Use a wooden hammer for the inspection.  
2. Using the hammer, lightly tap all around the wheel,  
carefully listening to the resulting sounds.  
3. Any places with fissures or cracks will result in a  
different sound.  
Do not use a wheel containing fissures or cracks.  
When installing a new grinding wheel, a no load  
revolution test of approximately one minute must be  
carried out with the grinding wheel facing a safe  
direction, i.e. away from people or objects.  
Fig. 6  
WARNING:  
DANGER:  
Do not attempt to operate this tool until you have read  
thoroughly and understand completely all instructions,  
safety rules, etc. contained in this manual. Failure to  
comply can result in accidents involving fire, electric  
shock, or serious personal injury. Save operator's manual  
and review frequently for continuing safe operation, and  
instructing others who may use this tool.  
Never attach a wood cutting or carving blade of any  
type to this angle grinder. It is only designed for  
grinding metal. Use for any other purpose is not  
recommended and creates a hazard which will result in  
serious injury.  
Page 10  
 
OPERATION  
(O) OFF  
(I) ON  
CAUTION:  
Never cover air vents. They must always be open for  
proper motor cooling.  
0
SWITCH BUTTON  
See Figure 7.  
To turn your grinder on, push the switch button forward.  
Release the button to turn the grinder off.  
SWITCH  
BUTTON  
LOCK-ON FEATURE  
OFF  
See Figure 7.  
ON  
Your grinder has a lock-on feature that is convenient when  
continuousoperationforextendedperiodsoftimeisrequired.  
To lock-on, push the switch button forward and press the  
front portion of the button in toward the grinder. To release  
the lock-on, press in on the rear portion of the button. Button  
will then disengage from the locked position.  
SWITCH BUTTON  
GRINDING  
See Figure 8.  
Always carefully select and use grinding wheels that are  
recommended for the material to be ground. Make sure that  
the minimum operating speed of the grinding wheel selected  
isnotlessthan11,000rpm.Thegrindingwheelprovidedwith  
your grinder is suitable for grinding welds, preparing sur-  
faces to be welded, grinding structural steel, and grinding  
stainless steel.  
TO  
LOCK-ON  
Fig. 7  
Secure all work before beginning a grinding operation.  
Secure small workpieces in a vise or clamp to a workbench.  
DANGER:  
0
Never use your grinder with the guard removed. It has  
been designed for use only with the guard installed.  
Attempting to use grinder with guard removed will result  
in loose particles being thrown against the operator  
resulting in serious personal injury.  
5° TO 15°  
Fig. 8  
15 degrees and continuously moving at a steady, consistent  
pace. Move the grinder back and forth or up and down over  
the work area. Keep the grinder moving so that an excessive  
amount of material is not removed from one area. If the  
grinder is held in one spot too long, it will gouge and cut  
grooves in the workpiece. If the grinder is held at too sharp  
an angle, it will also gouge the workpiece because of  
concentration of pressure on a small area.  
WARNING:  
Never use your grinder without wearing eye protection.  
Following this rule will reduce the risk of serious personal  
injury.  
The key to efficient operation begins by controlling the  
pressure and surface contact between the grinding wheel  
and workpiece. Flat surfaces are ground at an acute angle,  
normally between 5 to 15 degrees.  
Usejustenoughpressuretokeepthegrinderfromchattering  
or bouncing. Heavy pressure will decrease its speed and put  
a strain on the motor. Normally the weight of the tool alone  
is adequate for most grinding jobs. Use light pressure when  
grinding jagged edges or loose bolts where there is the  
potential for the grinder to snag on the metal edge.  
Formaximumcontrol, holdthegrinderinfrontandawayfrom  
you with both hands, keeping the grinding wheel clear of the  
workpiece. Start your grinder and let the motor and grinding  
wheel build up to full speed. Gradually lower grinder until the  
grinding wheel contacts the workpiece.  
Lift the grinder away from the workpiece before turning your  
grinder off.  
For best results keep the grinder tilted at an angle from 5 to  
Page 11  
 
MAINTENANCE  
WARNING:  
When servicing use only identical Ryobi replacement parts. Use of any other parts may create a hazard or cause product  
damage.  
GUARD REPLACEMENT  
See Figure 9.  
TO  
TIGHTEN  
After extended use, the guard may become worn and need  
adjustments or replacing. If you drop your grinder and  
damage the guard it may also be necessary for you to  
replace it.  
WRENCH  
TO  
LOOSEN  
CLAMP  
NUT  
PROCEED AS FOLLOWS WHEN REPLACEMENT IS  
REQUIRED:  
GRINDING  
WHEEL  
UNPLUG YOUR GRINDER.  
WARNING:  
Failure to unplug your grinder could result in accidental  
starting causing serious injury.  
DISC  
FLANGE  
GUARD  
Remove and reassemble parts as shown in figure 9.  
Depress spindle lock button and rotate clamp nut until  
spindle locks.  
Using the wrench provided, loosen and remove clamp  
CLAMP  
SCREW  
nut from spindle.  
Remove grinding wheel and disc flange.  
SPINDLE  
Using a screwdriver, loosen the clamp screw until the  
guard can be adjusted or removed.  
If you are making adjustments, rotate the guard to its  
correct position as shown in figures 4, 5, and 9, then  
retighten clamp screw securely. Never use your grinder  
without the guard in place and properly adjusted.  
See Figures 4, 5, and 6.  
FLAT(S)  
BEARING CAP  
Note: Be sure the tabs on the guard are seated in the  
groove in the bearing cap.  
SPINDLE  
LOCK BUTTON  
If you are replacing the guard, loosen the clamp screw  
Fig. 9  
until the guard can be removed from the bearing cap.  
Place the new guard on the shoulder of the bearing cap.  
See Figure 9.  
Note: If the new guard will not fit, loosen the clamp  
screw until the guard slides over the bearing cap.  
Rotate guard to the correct position as shown in figures 4,  
5, and 6.  
Tighten clamp screw securely.  
Note: Be sure the tabs on the guard are seated in the  
groove in the bearing cap.  
Reassemble disc flange, grinding wheel, and clamp nut.  
Refer to "INSTALLING THE GRINDING WHEEL" in-  
structions on page 9.  
Depress the spindle lock button and rotate the wheel  
clockwise until the spindle locks in position.  
Securely tighten the clamp nut with the wrench provided.  
Page 12  
 
MAINTENANCE  
GENERAL  
WARNING:  
Always wear safety goggles or safety glasses with side  
shieldsduringpowertooloperationorwhenblowingdust.  
If operation is dusty, also wear a dust mask.  
Avoidusingsolventswhencleaningplasticparts.Mostplastics  
are susceptible to damage from various types of commercial  
solvents and may be damaged by their use. Use clean cloths  
to remove dirt, carbon dust, etc.  
WARNING:  
LUBRICATION  
Do not at any time let brake fluids, gasoline, petroleum-  
based products, penetrating oils, etc. come in contact  
with plastic parts. They contain chemicals that can  
damage, weaken, or destroy plastic.  
All of the bearings in this tool are lubricated with a sufficient  
amount of high grade lubricant for the life of the unit under  
normaloperatingconditions. Therefore,nofurtherlubrication  
is required.  
WARNING:  
The double insulated system is intended to protect the  
user from shock resulting from a break in the tool's  
internal wiring. Observe all normal safety precautions  
related to avoiding electrical shock.  
Page 13  
 
OPERATOR'S MANUAL  
4 in. (100 mm) Angle Grinder  
Model AG400 / Double Insulated  
**Ampere rating  
(on tool data plate) 0-2.0  
EXTENSION CORD CAUTION  
2.1-3.4 3.5-5.0 5.1-7.0 7.1-12.0 12.1-16.0  
When using a power tool at a considerable distance from a power  
source, be sure to use an extension cord that has the capacity to  
handlethecurrentthetoolwilldraw. Anundersizedcordwillcause  
a drop in line voltage, resulting in overheating and loss of power.  
Use the chart to determine the minimum wire size required in an  
extension cord. Only round jacketed cords should be used.  
Cord Length  
Wire Size (A.W.G.)  
25'  
50'  
16  
16  
16  
16  
16  
16  
16  
16  
14  
16  
14  
12  
14  
14  
10  
14  
12  
100'  
When working with a tool outdoors, use an extension cord that is  
designed for outside use. This is indicated by the letters "WA" on  
the cord's jacket.  
CAUTION: Keep the extension cord clear of the working  
area. Position the cord so that it will not get caught on workpiece,  
tools, or other obstructions while you are working with a power  
tool.  
Before using any extension cord, inspect it for loose or exposed  
wires and cut or worn insulation.  
**Used on 12 gauge - 20 amp circuit.  
• SERVICE  
Now that you have purchased your tool, should a need ever exist for repair parts or service,  
simply contact your nearest Ryobi Authorized Service Center. Be sure to provide all  
pertinent facts when you call or visit. Please call 1-800-525-2579 for your nearest Ryobi  
complete list of Authorized Service Centers.  
• MODEL NO.  
The model number of your tool will be found on a plate attached to the motor housing.  
Please record the model number and serial number in the space provided below.  
MODEL NUMBER  
SERIAL NUMBER  
AG400  
RYOBI TECHNOLOGIES, INC.  
1428 Pearman Dairy Road Anderson SC 29625  
Post Office Box 1207 Anderson SC 29622  
Phone 1-800-525-2579  
972000-911  
 

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