OPERATOR’S MANUAL
7-1/4 in., 18 Volt
Compound Miter Saw
P551
45
BATTERY AND CHARGER
SOLD SEPARATELY
Your miter saw has been engineered and manufactured to our high standard for dependability, ease of operation, and
operator safety. When properly cared for, it will give you years of rugged, trouble-free performance.
WARNING: To reduce the risk of injury, the user must read and understand the operator’s manual before using
this product.
Thank you for your purchase.
SAVE THIS MANUAL FOR FUTURE REFERENCE
TABLE OF CONTENTS
Introduction ..................................................................................................................................................................... 2
Warranty .......................................................................................................................................................................... 2
General Safety Rules .................................................................................................................................................... 3-4
Specific Safety Rules .................................................................................................................................................... 4-5
Symbols ........................................................................................................................................................................... 6
Glossary of Terms ............................................................................................................................................................ 7
Features ...................................................................................................................................................................... 8-10
Tools Needed ................................................................................................................................................................. 10
Loose Parts List ............................................................................................................................................................. 11
Assembly .................................................................................................................................................................. 12-19
Operation .................................................................................................................................................................. 20-27
Adjustments ..............................................................................................................................................................28-29
Maintenance .................................................................................................................................................................. 30
Parts Ordering / Service ................................................................................................................................... Back Page
INTRODUCTION
This tool has many features for making its use more pleasant and enjoyable. Safety, performance, and dependability have
been given top priority in the design of this product making it easy to maintain and operate.
WARRANTY
RYOBI® POWER TOOL - LIMITED THREE YEAR WARRANTY AND 90 DAY EXCHANGE POLICY
One World Technologies, Inc., warrants its RYOBI® power tools with the following conditions:
90-DAY EXCHANGE POLICY: During the first 90 days after date of purchase, you may either request service under this
warranty or you may exchange any RYOBI® power tool which does not work properly due to defective workmanship or
materials by returning the power tool to the dealer from which it was purchased. To receive a replacement power tool or
requested warranty service, you must present proof of purchase and return all original equipment packaged with the original
product. The replacement power tool will be covered by the limited warranty for the balance of the three year period from
the date of the original purchase.
WHAT THIS WARRANTY COVERS: This warranty covers all defects in workmanship or materials in your RYOBI® power
tool for a period of three years from the date of purchase. With the exception of batteries, power tool accessories are warranted for ninety (90) days. Batteries are warranted for three years.
HOW TO GET SERVICE: Just return the power tool, properly packaged and postage prepaid, to an Authorized Service
Center. You can obtain the location of the Service Center nearest you by contacting a service representative at One
World Technologies, Inc., P.O. Box 1207, Anderson, SC 29622-1207, by calling 1-800-525-2579 or by logging on to
www.ryobitools.com. When you request warranty service, you must also present proof of purchase documentation, which
includes the date of purchase (for example, a bill of sale). We will repair any faulty workmanship, and either repair or replace
any defective part, at our option. We will do so without any charge to you. We will complete the work in a reasonable time,
but, in any case, within ninety (90) days or less.
WHAT’S NOT COVERED: This warranty applies only to the original purchaser at retail and may not be transferred. This
warranty only covers defects arising under normal usage and does not cover any malfunction, failure or defects resulting
from misuse, abuse, neglect, alteration, modification or repairs by other than Authorized Service Centers. One World Technologies, Inc. makes no warranties, representations or promises as to the quality or performance of its power tools other
than those specifically stated in this warranty.
ADDITIONAL LIMITATIONS: Any implied warranties granted under state law, including warranties of merchantability or
fitness for a particular purpose, are limited to three years from the date of purchase. One World Technologies, Inc. is not
responsible for direct, indirect, or incidental damages, so the above limitations and exclusions may not apply to you. This
warranty gives you specific legal rights, and you may also have other rights which vary from state to state.
2
GENERAL SAFETY RULES
WARNING:
Read and understand all instructions. Failure to follow
all instructions listed below, may result in electric shock,
fire and/or serious personal injury.
READ ALL INSTRUCTIONS
KNOW YOUR POWER TOOL. Read the operator’s manual
carefully. Learn the applications and limitations as well
as the specific potential hazards related to this tool.
GUARD AGAINST ELECTRICAL SHOCK BY PREVENT-
ING BODY CONTACT WITH GROUNDED SURFACES.
For example: pipes, radiators, ranges, refrigerator enclosures.
KEEP GUARDS IN PLACE and in good working order.
REMOVE ADJUSTING KEYS AND WRENCHES. Form
habit of checking to see that keys and adjusting wrenches
are removed from tool before turning it on.
KEEP WORK AREA CLEAN. Cluttered areas and benches
invite accidents. DO NOT leave tools or pieces of wood
on the tool while it is in operation.
DO NOT USE IN DANGEROUS ENVIRONMENTS. Do
not use power tools in damp or wet locations or expose
to rain. Keep the work area well lit.
KEEP CHILDREN AND VISITORS AWAY. All
visitors should wear safety glasses and be kept a safe
distance from work area. Do not let visitors contact
tool or extension cord while operating.
MAKE WORKSHOP CHILDPROOF with padlocks,
master switches, or by removing starter keys.
DON’T FORCE THE TOOL. It will do the job better and
safer at the feed rate for which it was designed.
USE THE RIGHT TOOL. Do not force the tool or attach-
ment to do a job for which it was not designed.
DRESS PROPERLY. Do not wear loose clothing,
neckties, or jewelry that can get caught and draw you into
moving parts. Rubber gloves and nonskid footwear are
recommended when working outdoors. Also wear
protective hair covering to contain long hair.
ALWAYS WEAR SAFETY GLASSES WITH SIDE
SHIELDS. Everyday eyeglasses have only impact-
resistant lenses, they are NOT safety glasses.
SECURE WORK. Use clamps or a vise to hold work
when practical, it is safer than using your hand and frees
both hands to operate the tool.
DO NOT OVERREACH. Keep proper footing and
balance at all times.
MAINTAIN TOOLS WITH CARE. Keep tools sharp
and clean for better and safer performance. Follow
instructions for lubricating and changing accessories.
USE RECOMMENDED ACCESSORIES. Consult the
operator’s manual for recommended accessories. The
use of improper accessories may result in injury.
NEVER STAND ON TOOL. Serious injury could occur if
the tool is tipped or if the cutting tool is unintentionally
contacted.
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 must
be properly repaired or replaced by an authorized service
center to avoid risk of personal injury.
USE THE RIGHT DIRECTION OF FEED. Feed work into
a blade or cutter against the direction of rotation of the
blade or cutter only.
NEVER LEAVE TOOL RUNNING UNATTENDED. TURN
THE POWER OFF. Don’t leave tool until it comes to a
complete stop.
PROTECT YOUR LUNGS. Wear a face or dust mask if
the cutting operation is dusty.
PROTECT YOUR HEARING. Wear hearing protection
during extended periods of operation.
KEEP BLADES CLEAN, SHARP, AND WITH
SUFFICIENT SET. Sharp blades minimize stalling
and kickback.
BLADE COASTS AFTER BEING TURNED OFF.
NEVER USE IN AN EXPLOSIVE ATMOSPHERE.
Normal sparking of the motor could ignite fumes.
KEEP TOOL 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 solvents to clean tool.
STAY ALERT AND EXERCISE CONTROL. Watch what
you are doing and use common sense. Do not operate
tool when you are tired. Do not rush.
DO NOT USE TOOL IF SWITCH DOES NOT TURN IT
ON AND OFF. Have defective switches replaced by an
authorized service center.
USE ONLY CORRECT BLADES. Do not use blades with
incorrect size holes. Never use blade washers or blade
bolts that are defective or incorrect. The maximum blade
capacity of your saw is 7-1/4 in.
BEFORE MAKING A CUT, BE SURE ALL ADJUST-
MENTS ARE SECURE.
BE SURE BLADE PATH IS FREE OF NAILS. Inspect for
and remove all nails from lumber before cutting.
NEVER TOUCH BLADE or other moving parts during
use.
3
GENERAL SAFETY RULES
NEVER START A TOOL WHEN ANY ROTATING COM-
PONENT IS IN CONTACT WITH THE WORKPIECE.
DO NOT OPERATE A TOOL WHILE UNDER THE
INFLUENCE OF DRUGS, ALCOHOL, OR ANY
MEDICATION.
WHEN SERVICING use only identical replacement parts.
Use of any other parts may create a hazard or cause
product damage.
DOUBLE CHECK ALL SETUPS. Make sure blade is
tight and not making contact with saw or workpiece
before connecting to power supply.
ENSURE THE SWITCH IS IN THE OFF POSITION
BEFORE INSERTING BATTERY PACK. Inserting the
battery pack into power tools that have the switch on
invites accidents.
RECHARGE ONLY WITH THE CHARGER SPECIFIED
BY THE MANUFACTURER. A charger that is suitabe for
one type of battery pack may create a risk of fire when
used with another battery pack.
USE POWER TOOLS ONLY WITH SPECIFICALLY DES-
IGNATED BATTERY PACKS. Use of any other battery
packs may create a risk of injury or fire.
FOR USE WITH 18 V NICKEL-CADMIUM AND 18 V
LITHIUM-ION BATTERY PACKS, see tool/appliance/
battery pack/charger correlation supplement 987000-432.
WHEN BATTERY PACK IS NOT IN USE, KEEP IT AWAY
FROM OTHER METAL OBJECTS LIKE PAPER CLIPS,
COINS, KEYS, NAILS, SCREWS, OR OTHER SMALL
METAL OBJECTS THAT CAN MAKE A CONNECTION
FROM ONE TERMINAL TO ANOTHER. Shorting the
battery terminals together may cause burns or a fire.
UNDER ABUSIVE CONDITIONS, LIQUID MAY BE
EJECTED FROM THE BATTERY; AVOID CONTACT. IF
CONTACT ACCIDENTALLY OCCURS, FLUSH WITH
WATER. IF LIQUID CONTACTS EYES, ADDITIONALLY
SEEK MEDICAL HELP. Liquid ejected from the battery
may cause irritation or burns.
DISCONNECT BATTERY PACK FROM TOOL OR PLACE
THE SWITCH IN THE LOCKED OR OFF POSITION
BEFORE MAKING ANY ADJUSTMENTS, CHANGING
ACCESSORIES, OR STORING THE TOOL. Such pre-
ventive safety measures reduce the risk of starting the
tool accidentally.
TOOL SERVICE MUST BE PERFORMED ONLY BY
QUALIFIED REPAIR PERSONNEL using only identical
replacement parts. This will ensure that the safety of the
power tool is maintained.
SPECIFIC SAFETY RULES
FIRMLY CLAMP OR BOLT the tool to a workbench or
table at approximately hip height.
KEEP HANDS AWAY FROM CUTTING AREA. Do not
reach underneath work or in blade cutting path with hands
and fingers for any reason. Always turn the power off.
ALWAYS SUPPORT LONG WORKPIECES while cutting
to minimize risk of blade pinching and kickback. Saw may
slip, walk or slide while cutting long or heavy boards.
ALWAYS USE A CLAMP to secure the workpiece when
possible.
BE SURE THE BLADE CLEARS THE WORKPIECE.
Never start the saw with the blade touching the
workpiece. Allow motor to come up to full speed
before starting cut.
MAKE SURE THE MITER TABLE AND SAW ARM
(BEVEL FUNCTION) ARE LOCKED IN POSITION
BEFORE OPERATING THE SAW. Lock the miter table
by pushing the miter lock lever down to lock. Lock the
saw arm (bevel function) by securely tightening the bevel
lock knob.
USE THIS SAW TO CUT WOOD, WOOD PRODUCTS
AND SOME PLASTICS ONLY. DO NOT CUT METALS,
CERAMICS OR MASONRY PRODUCTS.
NEVER USE A LENGTH STOP ON THE FREE SCRAP
END OF A CLAMPED WORKPIECE. NEVER hold onto
or bind the free scrap end of the workpiece in any operation. If a work clamp and length stop are used together,
they must both be installed on the same side of the saw
table to prevent the saw from catching the loose end and
kicking up.
NEVER cut more than one piece at a time. DO NOT
STACK more than one workpiece on the saw table at a
time.
NEVER PERFORM ANY OPERATION FREEHAND.
Always place the workpiece to be cut on the miter table
and position it firmly against the fence as a backstop.
Always use the fence.
4
SPECIFIC SAFETY RULES
NEVER hand hold a workpiece that is too small to be
clamped. Keep hands clear of the cutting area.
NEVER reach behind, under, or within three inches of the
blade and its cutting path with your hands and fingers for
any reason.
NEVER reach to pick up a workpiece, a piece of scrap,
or anything else that is in or near the cutting path of the
blade.
AVOID AWKWARD OPERATIONS AND HAND
POSITIONS where a sudden slip could cause your
hand to move into the blade. ALWAYS make sure you
have good balance. NEVER operate your miter saw
on the floor or in a crouched position.
NEVER stand or have any part of your body in line with
the path of the saw blade.
ALWAYS release the power switch and allow the saw blade
to stop rotating before raising it out of the workpiece.
DO NOT TURN THE MOTOR SWITCH ON AND OFF
RAPIDLY. This could cause the saw blade to loosen
and could create a hazard. Should this ever occur,
stand clear and allow the saw blade to come to a
complete stop. Disconnect your saw from the power
supply and securely retighten the blade bolt.
IF ANY PART OF THIS MITER SAW IS MISSING or
should break, bend, or fail in any way, or should any
electrical component fail to perform properly, shut off
the power switch, remove the miter saw plug from the
power source and have damaged, missing, or failed parts
replaced before resuming operation.
ALWAYS STAY ALERT! Do not allow familiarity (gained
from frequent use of your saw) to cause a careless
mistake. ALWAYS REMEMBER that a careless fraction
of a second is sufficient to inflict severe injury.
MAKE SURE THE WORK AREA HAS AMPLE LIGHTING
to see the work and that no obstructions will interfere with
safe operation BEFORE performing any work using your
saw.
THIS TOOL should have the following markings:
a) Wear eye protection.
b) Keep hands out of path of saw blade.
c) Do not operate saw without guards in place.
d) Do not perform any operation freehand.
e) Never reach around saw blade.
f) Turn off tool and wait for saw blade to stop before
raising saw arm, moving workpiece or changing
settings.
g) Disconnect the saw from the power source before
changing blade or servicing.
ALWAYS carry the tool only by the carrying handle.
THIS SAW CAN TIP OVER if the saw head is released
suddenly and the saw is not secured to a work surface.
ALWAYS secure this saw to a stable work surface before
any use to avoid serious personal injury.
AVOID direct eye exposure when using the laser guide.
SAVE THESE INSTRUCTIONS. Refer to them
frequently and use to instruct other users. If you loan
someone this tool, loan them these instructions also.
5
SYMBOLS
The following signal words and meanings are intended to explain the levels of risk associated with this product.
SYMBOL SIGNAL MEANING
DANGER:
WARNING:
CAUTION:
notice:
Some of the following symbols may be used on this tool. Please study them and learn their meaning. Proper
interpretation of these symbols will allow you to operate the tool better and safer.
Indicates an imminently hazardous situation, which, if not avoided, will result
in death or serious injury.
Indicates a potentially hazardous situation, which, if not avoided, could result
in death or serious injury.
Indicates a potentially hazardous situation, which, if not avoided, may result in
minor or moderate injury.
(Without Safety Alert Symbol) Indicates important information not related to an
injury hazard, such as a situation that may result in property damage.
SYMBOL NAME DESIGNATION/EXPLANATION
Safety Alert
Read Operator’s Manual
Eye Protection
Precautions that involve your safety.
To reduce the risk of injury, user must read and understand operator’s manual before using this product.
Always wear eye protection with side shields marked to comply
with ANSI Z87.1.
No Hands Symbol
Wet Conditions Alert
V Volts
min Minutes
n
o
.../min
No Load Speed
Per Minute
Failure to keep your hands away from the blade will result in
serious personal injury.
Do not expose to rain or use in damp locations.
Voltage
Time
Rotational speed, at no load
Revolutions, strokes, surface speed, orbits etc., per minute
6
GLOSSARY OF TERMS
Anti-Kickback Pawls (flooring, radial arm, and table saws)
A device which, when properly installed and maintained,
is designed to stop the workpiece from being kicked back
toward the front of the saw during a ripping operation.
Arbor
The shaft on which a blade or cutting tool is mounted.
Bevel Cut
A cutting operation made with the blade at any angle other
than 90° to the table surface.
Compound Cut
A cross cut made with both a miter and a bevel angle.
Cross Cut
A cutting or shaping operation made across the grain or the
width of the workpiece.
Cutterhead (planers and jointer planers)
A rotating cutterhead with adjustable blades or knives. The
blades or knives remove material from the workpiece.
Dado Cut
A non-through cut which produces a square-sided notch or
trough in the workpiece (requires a special blade).
Featherboard
A device used to help control the workpiece by holding
it securely against the table or fence during any ripping
operation.
FPM or SPM
Feet per minute (or strokes per minute), used in reference
to blade movement.
Freehand
Performing a cut without the workpiece being guided by a
fence, miter gauge, or other aids.
Gum
A sticky, sap-based residue from wood products.
Heel
Alignment of the blade to the fence.
Kerf
The material removed by the blade in a through cut or the
slot produced by the blade in a non-through or partial cut.
Kickback
A hazard that can occur when the blade binds or stalls,
throwing the workpiece back toward operator.
Miter Cut
A cutting operation made with the workpiece at any angle
to the blade other than 90°.
Non-Through Cuts
Any cutting operation where the blade does not extend
completely through the thickness of the workpiece.
Pilot Hole (drill presses)
A small hole drilled in a workpiece that serves as a guide for
drilling large holes accurately.
Push Blocks (jointer planers)
Device used to feed the workpiece over the jointer planer
cutterhead during any operation. This aid helps keep the
operator’s hands well away from the cutterhead.
Push Blocks (flooring and table saws)
Device used to hold the workpiece during cutting operations. This aid helps keep the operator’s hands well away
from the blade.
Push Sticks (flooring and table saws)
Device used to push the workpiece during cutting operations.
A push stick should be used for narrow ripping operations.
The aid helps keep the operator’s hands well away from
the blade.
Resaw
A cutting operation to reduce the thickness of the workpiece
to make thinner pieces.
Resin
A sticky, sap-based substance that has hardened.
Revolutions Per Minute (RPM)
The number of turns completed by a spinning object in one
minute.
Ripping or Rip Cut
A cutting operation along the length of the workpiece.
Riving Knife/Spreader/Splitter (flooring and table saws)
A metal piece, slightly thinner than the blade, which helps
keep the kerf open and also helps to prevent kickback.
Saw Blade Path
The area over, under, behind, or in front of the blade. As it
applies to the workpiece, that area which will be or has been
cut by the blade.
Set
The distance that the tip of the saw blade tooth is bent (or
set) outward from the face of the blade.
Snipe (planers)
Depression made at either end of a workpiece by cutter
blades when the workpiece is not properly supported.
Through Sawing
Any cutting operation where the blade extends completely
through the thickness of the workpiece.
Throw-Back
The throwing back of a workpiece usually caused by the
workpiece being dropped into the blade or being placed
inadvertently in contact with the blade.
Workpiece or Material
The item on which the operation is being done.
Worktable
Surface where the workpiece rests while performing a
cutting, drilling, planing, or sanding operation.
7
FEATURES
PRODUCT SPECIFICATIONS
Arbor ......................................................................... 5/8 in.
Blade Diameter ......................................................7-1/4 in.
No Load Speed .................................... 4,500 r/min. (RPM)
Motor .................................................................. 18 Volt DC
“d” handLe
switch
Lock
upper
dust
bag
bLade
guard
Cutting Capacity with Miter at 0°/Bevel 0°:
Maximum lumber sizes ..................... 1-1/2 in. x 4-1/4 in.
Cutting Capacity with Miter at 45°/Bevel 0°:
Maximum lumber sizes ............................1-1/2 in. x 3 in.
Cutting Capacity with Miter at 0°/Bevel 45°:
Maximum lumber sizes ..................... 1-1/2 in. x 3-1/2 in.
Cutting Capacity with Miter at 45°/Bevel 45°:
Maximum lumber sizes ............................1-1/2 in. x 3 in.
bLade
Miter
wrench
Lock Lever
Laser
guide
switch
trigger
beveL
Lock
knob
Miter
fence
base
45
work
cLaMp
Lower
bLade
guard
“no hands Zone”
boundarY Line
Miter
tabLe
“no hands
Zone” LabeL
throat
pLate
Miter
scaLe
45
33.9
30
15
0
1
2
3
4
5
beveL
scaLe
Fig. 1
8
45
33.9
30
15
1
2
3
4
5
6
FEATURES
KNOW YOUR COMPOUND MITER SAW
See Figure 1.
The safe use of this product requires an understanding of
the information on the tool and in this operator’s manual as
well as a knowledge of the project you are attempting. Before
use of this product, familiarize yourself with all operating
features and safety rules.
7-1/4 in. BLADE
A 7-1/4 in. blade is included with the compound miter saw.
It will cut materials up to 1-1/2 in. thick or 4-1/4 in. wide,
depending upon the angle at which the cut is being made.
BEVEL LOCK KNOB
The bevel lock knob securely locks your compound miter
saw at desired bevel angles. Positive stop adjustment
screws have been provided on each side of the saw arm.
These adjustment screws are for making fine adjustments
at 0° and 45°.
BLADE WRENCH STORAGE
See Figure 1.
A blade wrench is packed with the saw. One end of the wrench
is a phillips screwdriver and the other end is a hex key. Use
the hex key end when installing or removing blade and the
phillips end when removing or loosening screws. A storage
area for the blade wrench is located in the saw’s base.
LASER GUIDE
See Figure 2.
For more accurate cuts, a laser guide is included with your
miter saw. When used properly, the laser guide makes accurate, precision cutting simple and easy when the laser
switch is turned on.
Miter
Lock Lever
Laser switch
“d” handLe
Lock
pin
saw arM Locked
in down position
rear bracket/
carrYing handLe
Fig. 2
switch
trigger
MITER FENCE
The miter fence on the compound miter saw has been
provided to hold your workpiece securely against when
making all cuts.
MITER LOCK LEVER
See Figure 2.
The miter lock lever securely locks the saw at desired miter
angles.
POSITIVE STOPS ON MITER TABLE
Positive stops have been provided at 0°, 15°, 22-1/2°,
31.62°, and 45°. The 15°, 22-1/2°, 31.62°, and 45° positive
stops have been provided on both the left and right side of
the miter table.
REAR BRACKET/CARRYING HANDLE
See Figure 2.
For convenience when carrying or transporting the miter
saw from one place to another, a carrying handle has been
provided at the rear of the saw. To transport, turn off and
remove the battery pack from the tool, then lower the saw
spindLe
Lock button
Fig. 3
arm and lock it in the down position. Lock saw arm by depressing the lock pin.
SELF-RETRACTING LOWER BLADE GUARD
The lower blade guard is made of shock-resistant, seethrough plastic that provides protection from each side of
the blade. It retracts over the upper blade guard as the saw
is lowered into the workpiece.
SPINDLE LOCK BUTTON
See Figure 3.
The spindle lock button locks the spindle stopping the
blade from rotating. Depress and hold the lock button while
installing, changing, or removing blade.
9
FEATURES
SWITCH TRIGGER
See Figure 4.
The saw will not start until you depress the switch lock with
your thumb then squeeze the switch trigger. To prevent
unauthorized use of the compound miter saw, remove the
battery pack, and lock the switch in the off position. To lock
the switch, install a padlock (not included) through the hole
in the switch trigger. A lock with a long shackle of 5/16 in.
diameter may be used. When the lock is installed and locked,
the switch is inoperable. Store the padlock key in another
location.
switch
Lock
switch
trigger
TOOLS NEEDED
The following tools (not included) are needed for making adjustments or installing the blade:
padLock
Fig. 4
fraMing square
coMbination square
Fig. 5
10
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