Magnum Industrial MI-15550 User manual

MODEL NO.: MI-15550
OPERATING MANUAL
ON
STOP
MODEL NO.:
MFG. NO.:
SERIAL NO.:
MI-15550 AMP.
R.P.M.
DATE
CSA
10
1800
H.P.
VOLT
H.Z.
PHASE
2
230
60
1
:
:
:
:
:
:
:
:
180264
MADE IN TAIWAN / FABRIQUÉ EN TAIWAN
WARNING AVERTISSEMENT
!!
• TO REDUCE RISK OF INJURY READ
INSTRUCTION MANUAL.
• ALWAYS USE GUARDS AND TOOL RESTS.
• ALWAYS WEAR EYE PROTECTION.
• USE GRINDING WHEELS WITH A SPEED
RATING SUITABLE TO THIS GRINDER.
• BOLT DOWN THE BENCH GRINDER BEFORE
USING.
• DO NOT EXPOSE TO RAIN OR USE IN DAMP
LOCATIONS.
• POUR RÉDUIRE LES RISQUES D'INCIDENTS
LIRE LE MANUEL D'INSTRUTION.
• TOUJOURS UTILISER AVEC LE
PARE-ÉTINCELLES.
• TOUJOURS UTILISER LES LUNETTES DE
PROTECTIONS.
• EMPLOYER DES MEULES ABRA- SIVES
ADAPTÉES À LA VITESSE DECE TOURET.
• NE PAS EXPOSER À LA PLUIE OU UTILISER
DANS DES EMPLACE- MENTS HUMIDES.

12" Bench Grinder with Stand
Operating Instructions & Parts Manual
Please read and save these instructions. Read carefully before attempting to assemble, install,
operate or maintain the product described. Protect yourself and others by observing all safety
information. Failure to comply with instructions could result in personal injury and'or property damage!
Retain instructions for future reference.
Description
12" Bench Grinder is equipped with a totally enclosed ball bearing motor. Armature assembly is
dynamically balanced for smooth operation. Motor housing is compact so long pieces of work can
press against both wheels without touching the motor frame. Removable wheel guards allow for easy
changing of wheels. Two-way tool rests are adjustable for wheel wear and angle grinding. comes
complete with spark guards, safety eyeshields, dust collection hose and stand.
Unpacking
Check for shipping damage. If damage has occurred, a claim must be filed with the carrier
immediately. Check for com- pleteness. Immediately report missing parts to dealer. To be certain the
grinding wheels have not been damaged in shipment, strike the edges slightly with a metal object. A
ringing sound indicates a good wheel, but a dull noise may signal a fracture.
WARNING If you suspect a wheel of being fractured, replace it immediately. Fractured wheels
may shatter, causing serious injury.
Specications
Model HP RPM AMPS Volts Hz
MI-15550 2 1800 10 230 60
ALUMINUM OXIDE VITRIFIED WHEELS
GRIT
1 ea. 36 Coarse and 1 ea. 60 Medium
SZIS
12" Dia., 2" Face, 14" Bore
General Safety Information
WARNING For your own safety, read operating instructions manual befors operating tool.
BE PREPARED FOR JOB
1. Wear proper apparel. Do not wear loose clothing, gloves, neckties, rings, bracelets or other jewelry
which may get caught in moving parts of machine.
2. Wear protective hair covering to contain long hair.
3. Wear safety shoes with non-slip soles.
4. Wear safety glasses complying with United States ANSI Z87.1. Everyday glasses have only impact
resistant lenses. They are NOT safety glasses.
5. Wear face mask or dust mask if operation is dusty.
6. Be alert and think clearly. Never operate power tools when tired, intoxicated or when taking
medications that cause drowsiness.
PREPARE WORK AREA FOR JOB
1. Keep work area clean. Cluttered work areas and work benches invite accidents.
2. Do not use power tools in dangerous environments. Do not use power tools in damp or wet
locations. Do not expose power tools to rain.

3. Work area should be properly lighted.
4. Proper electrical plug should be plugged directly into properly grounded, three-prong receptacle.
5. Extension cords should have a grounding prong and the three wires of the extension cord should
ba of the correct gauge.
6. Keep visitors at a safe distance from work area.
7. Keep children out of the workplace. Make workshop childproof. Use padlocks, master switches or
remove switch keys to prevent any uninten- tional use of power tools.
TOOL SHOULD BE MAINTAINED
1. Always unplug tool prior to inspection.
2. Consult manual for specic maintain- ing and adjusting procedures.
3. Keep tool clean for safest operation.
4. Remove adjusting tools. Form habit of checking to see that adjusting tools are removed before
turning machine
5. Keep all parts in working order. Check to determine that the guard or other parts will operate
properly and perform their intended function.
6. Check for damaged parts. Check for alignment of moving parts, binding of moving parts, breakage
of parts, mounting and any other condition that may a󰀨ect a tool's operation.
7. A guard or other part that is damaged should be properly repaired or replaced. Do not perform
makeshift repairs. (Use the parts list to order repair parts.)
KNOW HOW TO USE TOOL
1. Use right tool for job. Do not force tool or attachment to do a job for which it was not designed.
2. Disconnect tool from power when changing accessorics such as grinding wheels, bu󰀩ng wheels
and the like.
3. Avoid accidental start-up. Make sure that the switch is in the OFF position before plugglng in.
4. Do not force tool. It wll work most e󰀩ciently at the rate for which it was designed.
General Safety Information (Continued)
5. Keep hands away from moving parts and grinding surfaces.
6. Never leave a tool running unat- tended. Turn the power o󰀨 and do not leave tool until it comes to
a complete stop.
7. Do not overreach. Keep proper footing and balance.
8. Never stand on tool. Serious injury could occur if tool is tipped over.
9. Know your tool. Learn the tool's operation, application and specic limitations.
10. Use recommended accessories. Understand and obey all safety instructions supplied with
accessories. The use of improper accessories may cause risk of injury to persons.
11. Do not over tighten wheel nut. Replace cracked wheel immediately. Use only anges supplied
with the grinder.
12. Adjust distance between wheel and tool rest to maintain 1/16" or less gap.
13. Handle the workpiece correctly. Whenever possible, use tool rest to support workpiece during
grinding operation. Turn tool o󰀨 if it jams.
14. Always use guards and eyeshields.
15. Clean grinding dust from beneath tool frequently.
Assembly
Parts to be fastened to the grlnder should be located and accounted for (See List and Figure 1).
IMPORTANT: Do not attempt assembly If parts are missing. Use this manual to order repair parts.

A 5/16-18 x 1" Carriage bolt, 4 each
B Tool rest bracket, 4 each
C *3/8" Flat washer, 8 each
D *3/8"-16 Hex nut, 2 each
E Tool rest, 2 each
F 5/16" Flat washer, 4 each
G 5/16"-18 Hex nut, 4 each
H *3/8-16 x 14" Hex bolt, 6 each
I Knob, 2 each
J Spark guard, 2 each
K Eyeshield, 2 each
L *Lower eyeshield bracket, 2 each
M Upper eyeshield bracket, 2 each (left and right)
N #10-24 x 3/8" Pan head screw, 4 each
O 6-1.0 x 12mm Flange screw, 2 each
P 6mm Flat washer, 2 each
Q *3/8"-16 Wing nut, 2 each
R *Wheel guard
S 3/8-16 x 5/8" Hex bolt, 4 each
T *Wheel guard cover
U Dust collector hose (not shown)
NOTE: Parts marked with an asterisk (*) are mounted to the grinder at the factory.
TOOL REST ASSEMBLY
Slide 5/16-18" carriage bolts (A) into square holes in tool rest brackets (B). Slide carriage bolts with
brackets into holes on inside of tool rest (E) as shown in Figure 1. Slide 5/16" at washers (F) and
5/16"-18 hex nuts (G) onto carriage bolts. Tighten nuts nger tight. Remove 3/8" hex nuts (D) and at
wash- ers (C) from 3/8-16 x 14" hex bolts (H) mounted to bottom front of left wheel guard (R). Slide
slot in tool rest bracket (right side) over 3/8" bolts. Replace at washers and hex nuts. Position left
side tool rest bracket over threaded holes in wheel guard cover and secure with 3/8" flat washers
(C) and 3/8-16 x 5/8“ hex bolts (S). Position tool rest so that distance between tool rest and grinding
wheel is less than 1/16". Secure all nuts and bolts. Mount right tool rest in a similar manner.
EYESHIELD ASSEMBLY
Remove 3/8" wing nut (Q) and 3/8" at washer (C) from 3/8-16 x 14" hex bolt (H) mounted to top front
of left wheel guard (R). Slide slot in spark guard (J) over hex bolt and replace washer and wing nut.
Remove pan head screws (N) from eyeshield assembly. Mount left upper eyeshield bracket (M) to
eyeshield using pan head screws and lower eyeshield bracket.
NOTE: Left upper eyeshield bracket is stamped "L" for identication. Slide 6-1.0 x 12mm ange screw
(0) and 6mm at washer (P) through left upper eyeshield bracket (M) and through hole at top of left
spark guard (J) and secure with knob (1).
Assembly (Continued)
Locate eyeshield in desired position for protecting operator and secure all nuts and bolts. Mount right
eyeshield assembly in a similar manner.
DUST COLLECTOR HOSE
A dust collector hose has been provided with grinder. Slide hoses onto sides of T-connector and
anges. Mount the hose by sliding the anges at each end over the exhaust ports on the left and right
wheel guards. Attach 22" shop vacuum hose to collector hose. Be sure hase is mounted securely. Be
sure to empty

DANGER Be sure to empty shop vacuum of all ammable material (ammable liquids and
vapors, paper, wood, plastic, etc.) before connecting vacuum to grinder. Hot sparks from
grinder may ignite ammable materials in shop vacuum.
OPTIONAL LIGHTED EYESHIELD
Positlon eyeshleld bracket assembly over bosses provided on wheel guard. Bosses are tapped to
receive two 1/4"- 20 screws. Fasten bracket assembly to wheel guard with two screws provided with
eyeshields.
GROUNDING INSTRUCTIONS
WARNING Improper connection of equipment grounding conductor can result in the risk
of electrical shock. Equipment should be grounded while in use to pro- tect operator from
electrical shock.
Check with a qualied electrician if grounding instructions are not under- stood or if in doubt as to
whether the tool is properly grounded. This grinder is equipped with an approved 3-conductor cord
rated at 300V. Do not remove or alter grounding prong in any manner. In the event of a malfunction or
breakdown, grounding provides a path of least resistance for electrical shock.
WARNING Do not permit n-gers to touch the terminals of plug when installing or removing
from outlet.
Plug must be plugged into matching outlet that is properly installed and grounded in accordance with
all local codes and ordinances. Inspect tool cords periodically, and, if damaged, have repaired by
an authorized service facility. Green (or green and yellow) conductor in cord is the grounding wire. If
repair or replacement of the electric cord or plug is necessary, do not connect the green (or green and
yellow) wire to a live terminal.
Installation
POWER SOURCE
12" grinder is prewlred for 230 volts, 60 Hz, single-phase power. A qualied electrician should wire a
230 volt, 20 AMP, 3-prong plug to grinder line cord.
WARNING All electrical connec- tions must be per- formed by a qualied electrician.
EXTENSION CORDS
1. The use of any extension cord will cause some drop in voltage and loss of power.
2. Wires of the extension cord must be of su󰀩cient size to carry the current and maintain adequate
voltage.
3. Running the unit on voltages which are not within +10% of the specied voltage may cause
overheating and motor burn-out.
4. Use the table to determine the mini- mum wire size (A.W.G.) extension cord.
5. Use only 3-wire extension cords hav- Ing 3-prong grounding type plugs and 3-pole receptacles
which accept the tool plug.
6. If the extension cord is worn, cut or dam- aged in any way, replace it immediately.
EXTENSION CORD LENGTH
Wire Size A.W.G.
Up to 25 ft. 14
NOTE: Using extension cords over 25 ft. long is not recommended.
ELECTRICAL CONNECTIONS
WARNING All electrical connec-tions must be per- formed by a qualied electrician. Make
sure tool is off and disconnected from power source while motor is mounted, connected,
reconnected or anytime wiring is inspected,

Operation
WARNING Always wear safety glasses complying with United States ANSI Z87.1 (shown
on package) before commencing power tool operation. Safety glasses are avaiI- able through
your Grainger catalog.
1. Keep a steady, moderate pressure on the work and keep it moving at an even pace for smooth
grinding.
2. Pressing too hard overheats the motor and prematurely wears down the grinding wheels.
3. Note the original bevel angle on the item to be sharpened and try to maintain that angle.
Sharpening a cutting edge requires removing burrs from edge.
4. Deburring edge is done best by using the grinder to pull burr from edge across the bevel angle.
5. The grinding wheel should rotate into object being sharpened.
6. Dip work into a coolant regularly to prevent overheating. Overheating can weaken metals.
Maintenance
1. As wheels wear, tool rests should be positioned closer to the face of the wheels.
2. The gap between the wheel and the tol rest should not be greater than 1/16*. When the wheels are
worn to the extent that the 1/16" maxi gap cannot be maintained, the wheels should be replaced.
3. Replacement wheels should have a minimum rated speed of at least 1800 RPM.
4. Maximum wheel diameter is 12"
5. To loosen nuts holding the vwheels, disconnect power and push a wood wedge between the tool
rest and the wheel to keep the shaft from turning. The threads on the right side of the grinder (facing
unit) are right hand; threads on the left side are left hand. Tighten nuts securely before operating
the grinder.
6. For grinding e󰀩ciency, wheels should be dressed periodically, especlally if they become clogged
from grinding soft metals.

Troubleshooting Chart
Symptom Possible Cause(s) Corrective Action
Grinder won’t start
1. Blown line fuse or tripped circuit
breaker
2. Low line voltage
3. Material wedged between wheel and
guard
4. Defective switch
5. Defective, blown capacitor
1. If fuse is blown, replace with fuse of
proper size. If breaker tripped, reset it
2. Check power supply for voltage and
correct as needed
3. Turn grinder o󰀨 and remove material
4. Replace switch
5. Replace capacitor
Excessive vibration
1. Improper mounting of grinder
accessories
2. Grinding wheel out of balance
3. Improper wheel mounting
1. Remount
2. Dress wheels or replace wheels
3. Remount wheels, but rotate one wheel
90° with respect to its previous
position. Other wheel should remain in
its original position
Motor overheating
1. Excess pressure required to grind
material
2. Grinding on side of wheel
3. Motor not turning freely
(without power)
1. Dress wheel or replace wheel with
one of proper grit
2. Grind only on face of wheel
3. Clean around wheels and shaft and/or
replace bearings
Fuses are being or circuit
breakers are being tripped
1. Overloading due to binding
2. Defective plug
3. Defective cord
4. Faulty internal wiring
1. Clean around wheels and shaft and/or
replace bearings
2. Replace plug
3. Replace cord
4. Contact authorized MAGNUM Service
Center

PARTS LIST FOR MI-15550

yt'QNOITPIRCSED.ONMETIyt'QNOITPIRCSED.ONMETI
MI-15550-01 1/4-20 x 3/4" Pan head screw 10 MI-15550-36 Grinding wheel (60 med. grit) 1
daerhtHR(tunxeH8-"173-05551-IM2revocdraugleehW20-05551-IM ) 1
2tserlooT83-05551-IM1)daerhtHL(tunxeH8-"130-05551-IM
4tlobegairraC"41x81-61/593-05551-IM2egnalF40-05551-IM
MI-15550-05 Grinding wheel (36 coarse grit) 1 MI-15550-40 5/16" Fla 4rehsawt
8tunxeH81-"61/514-05551-IM2egnalfleehwrennI60-05551-IM
MI-15550-07 5/16-18 x 5/8" Hex head bolt 6 MI-15550-42 Tool rest up 4thgir
4tunxeH61-"8/334-05551-IM4rehsawkcoL"61/580-05551-IM
MI-15550-09 3/8-16 x 14" hex head bolt 6 MI-15550-44 #10 Serrated w 1rehsa
21we
rcSegnalF"4/1x42-01#54-05551-IM2draugleehW01-05551-IM
1temmorG64-05551-IM2dleihseyE11-05551-IM
1droceniL74-05551-IM2tekcarbdleihseyerewoL21-05551-IM
1feilerniartS84-05551-IM2wercsegnalFmm21x0.1-631-05551-IM
1etalpfeilerniartS94-05551-IM2rehsawtalFmm641-05551-IM
MI-15550-15 Upper eye shield bracket (left) 1 MI-15550-50 Capacitor 1pmalc
4roticapaC15-05551-IM4wercsdaehnaP"8/3x42-01#61-05551-IM
1pacroticapaC25-05551-IM1)2fotes(draugkrapS71-05551-IM
1revocesaB35-05551-IM8rehsawtalF"8/381-05551-IM
1roticapaC45-05551-IM2tungniW61-"8/391-05551-IM
1kcolblanimreT55-05551-IM2bonK02-05551-IM
2teviR65-05551-IM2dleihsdnE12-05551-IM
1revoC75-05551-IM8wercsegnalF"2x02-4/122-05551-IM
1esaB85-05551-IM1esohrotcelloctsuD32-05551-IM
lobdaehxeH"8/5x61-8/595-05551-IM2ZZ7006gniraeB42-05551-IM t 4
1nafrotoM52-05551-IM Recommended Accessories
1gnisuohhtiwrotatS62-05551-IM ▲1dleihseyedethgiL
1erutamrA72-05551-IM ▲Grinding wheel dresser 1
MI-15550-28 #10-24 x 3/8" Flange screw 7
1rotcatnoccitengaM92-05551-IM
MI-15550-30 1/4-20x5/8" Flat Head Screw 2
MI-15550-31 Magnetic switch holder 1
1hctiwsyranoitatS23-05551-IM
1hctiwsgnitatoR33-05551-IM
1rehsawyvaW43-05551-IM
MI-15550-35 Upper eye shield bracket (right) 1
(
▲
)
Not shown.
(
*
)
Standard hardware item, available locall
y
.
(
+
)
Not available as re
p
air
pa
PARTS LIST FOR MI-15550