Portable Grinder Safety
Background
The portable grinder is used in the field or
maintenance shop to grind excess metal
from welds, remove rust, and for special
finishing operations.
Since this tool is hand operated, the quality of
the work depends upon the ability and
experience of the operator …
as does safe job completion.
October 2012
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Background, continued
Since the grinder is such a
common tool
(you will find one or more on almost every
maintenance or construction job)
Perceived Risk
the risks involved with them may
tend to be taken for granted
Frequency
Low Personal Awareness !!
October 2012
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What are the Common Hazards of
Portable Grinder Use?
 High speed flying particles … a grinding wheel’s speed
can be greater than a mile a minute
 from the grinding wheel itself
 from the work piece being ground
 Inhaling dust and fumes generated
 Explosion or fire
 if sparks ignite flammable or combustible materials
nearby or below grinding operation
 Electric shock from frayed or defective power cord
 Noise
 Musculoskeletal disorders (MSDs) from
 repetitive use
 awkward body positions
October 2012
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Common Injuries Due to
Grinders/Grinding Activities
 Cuts
 Strains
 Particles in the eye
October 2012
Grinders have
contributed to
fatalities !!!
(flying particles cutting
major artery for example)
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Common Causes of Grinding
Incidents
 Using the wrong wheel
 for the job or grinder
 Improper mounting
 of wheel or guard
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Careless handling
Repetitive motion
Improper PPE use
Improper use of grinder
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Critical Grinder Wheel Safety
Issues
Some Grinding wheels can be surprisingly delicate.
They can be easily damaged if handled
carelessly.
 Store new wheels carefully in a dry area close
to the grinding operation.
 When you have to carry one, do it very
carefully.
 Take special care not to drop it or to bump it
against anything.

Never use a wheel that has been dropped or
received a heavy blow, even if there is no
apparent damage.
 Replace wheels that are badly worn or
cracked.
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Using the Right Wheel

Ensure the wheel is designed for the machine’s size and
speed and the material of construction of the work piece

Grinding disks are made from varying types of abrasive
materials. They are classified according to weight, size, arbor
hole size (hole in the middle) and Rotations Per Minute (RPM)
and material to be used on. This information can be found on
the disk.
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Grinding blades are to be used for GRINDING only, DO NOT
use to cut material. Use only the grinding face, not the back
side of disk.
Cutting blades are classified according to size, bearing arbor
hole size and thickness. This information is also found on the
blades.
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October 2012
Cutting blades are used for CUTTING only. DO NOT grind with
them. Use only the edge.
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Wheel Example
Cutting Blade
Max RPM
Size of Disk
Type of Material
can be used on
October 2012
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Wheel Mounting Safety
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Disconnect power source before adjusting, oiling or changing accessories
Use only parts supplied or approved by the grinder's manufacturer
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nuts, flanges, guards, blotters, etc.
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the grinder motor should burn up rather than the wheel flying apart

Gently tap a dry clean wheel with a light nonmetallic tool—perhaps screwdriver
handle for light wheels or wooden mallet for heavier ones
The tap should produce a clear metallic “ping.” If the sound is more like a dull thud,
the wheel is probably cracked and shouldn’t be used.
Ensure wheel maximum speed is higher than grinder maximum speed
Inspect wheel or attachment for cracks or flaws
Clean wheel and grinder
Perform a “ring test” on wheels prior to mounting (not applicable to all type wheels
or other attachments and accessories)
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Be sure the wheel fits freely on the spindle.
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The spindle nut must be tightened enough to hold the wheel in place, without
distorting the flange
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October 2012
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Check that the arbor hole is the proper size for the grinder to be used
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some manufactures require wrenches for tightening the wheel
Ensure guard is replaced in the appropriate position
After mounting wheel or brush and replacing the guard, stand to the side and allow
a one minute run-up at no load to test integrity and balance of the wheel
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Other Accessories or
Attachments
 Do not use unless:
 The manufacturer recommends or approves
its use on the product
 The accessory limitations and specifications
match those of the grinder
 speed, size, mounting and guarding
requirements, etc.
 The use of the accessory does not require the
removal of or defeating of any guards,
barriers or other safety-related devices
 unless they are replaced by other appropriate
guards or protective devices.
Follow manufacturer’s instructions for
mounting approved accessories or attachments.
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Guard Mounting Safety
 Grinders come equipped with
a wheel guard that must
remain in place at all times
to protect the operator from
flying sparks and material
 Never operate without its
guard in the proper place
 Use a guard supplied or
approved by the tool
manufacturer
 Report any missing, broken,
or disabled guards
“Proper” placement of tool
guard may vary. Handles
can be moved on some
angle grinders (to allow for
right or left handed
operation).
Unlike in the photo above,
the guard must be between
the handle and the wheel.
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Proper Handling of Grinders
 Always use two hands when using a
portable grinder
 To maintain control
 The high speeds of the wheel can cause the
grinder to fly off the metal
 To keep both hands away from the hazard of the
high speed rotation
 if a hand or finger hits the moving wheel
surface, injuries will result
 if grinding on small pieces, may need to secure
the work in a vise … DO NOT HOLD IN YOUR
HAND
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Repetitive Motion Precautions
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Use firm hand grip force for control but without excessive force
Avoid anything that inhibits blood circulation.
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Avoid continuous vibration exposure.
Keep wrists as straight as possible
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After each period of extended operation, exercise to increase
blood circulation
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squatting for extended periods
improperly fitted gloves
other restrictions to comfortable body mechanics
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Avoid repeated bending of wrists and hands.
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flex wrists
change body position
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to maintain better control of the tool and better body position
Minimize extent of reaching
To prevent potential repetitive motion injuries consider the need to
reposition the work piece or your body
rotate job duties
change work pace
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Proper Grinder PPE

Goggles AND a full face shield
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Leather Gloves
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to protect your hands from flying particles and sharp edges created during the grinding
operation, as well as the edge of the wheel itself
Hearing protection
Proper attire
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to prevent chips or particles from getting into your eyes
 particles WILL fly in any grinding operation
 take appropriate precautions on removing goggles or safety glasses to ensure
particles don’t fly into your eye even AFTER the grinding operation is done
don’t wear anything loose that could get caught in the rotation
 secure scarves, ties, loose hair, and dangling jewelry
if you’re wearing a long-sleeved shirt, button it at the wrist
Consider also the possible need for a dust mask
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may be required for some grinding operation, depending upon the material of
construction of the work piece being ground
Be sure to maintain use of PPE for as long as hazard remains !!!
Jan 2006
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Proper Use of Grinders
 Unless otherwise designed, grind on
the face of the wheel.
 serious injury or damage could occur if
the side of the wheel is used
 use disc wheels for side-grinding
 light side-grinding is permissible on cup or
saucer wheels
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Critical Safe Behaviors for all
Powered Tools
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Know and Follow all Manufacturer’s Instructions
Use tool only for its intended purpose
Maintain tools in proper condition
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sharp & clean, lubricated
all guards in place
ensure any repairs performed by qualified persons
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to force pieces that don’t fit
or otherwise use the tool for an unintended purpose
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use appropriate grounding
Do not alter tools
Perform a prior to use inspection of the tool
Protect against electrical shock
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October 2012
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ground plug in place, GFCI as appropriate
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don’t abuse cords, keep away from heat, oil & sharp edges,
inspect for frays, cuts, etc.
inspect cords & connections
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Critical Safe Behaviors for all
Powered Tools, continued
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Ensure all guards, grips, handles, etc. are in place
Prevent unintentional starting of the tool
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2 motion positive on/off switch required
don’t carry powered tools plugged in with finger on switch
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don’t allow cords to become trip hazards
minimize number of employees in hazard zone
Never carry a tool by the cord or hose.
Never yank the cord or the hose to disconnect cord
Avoid accidental starting. Do not hold a finger on the switch button
while carrying a plugged-in tool.
All portable electric tools that are damaged shall be removed from
use and tagged "Do Not Use.“
Protect others in work area
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ensure all in hazardous areas are using appropriate PPE
consider work in adjacent or below areas
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Additional Grinder Specific
Critical Behaviors
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Allow grinder to come to full speed before contacting work
surface
Remove material or debris that might be ignited by sparks
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Do not grind non-ferrous materials.
Maintain steady pressure on the work piece
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Do not apply excessive pressure to the wheel or disc so that the
motor slows noticeably of the work gets hot
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Keep a properly charged fire extinguisher available
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sudden “bumping”, pounding or impact could damage the wheel
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could stress the wheel, overheat the work piece and reduce your control
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could cause the work to burn or the wheel to crack and explode.
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A portable grinder can kick and glance off the work if not properly
controlled
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Avoid letting the wheel rest on one spot for too long.
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Keep good footing and maintain good balance
Never attempt to grind in an awkward position.
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Allow grinder to come to complete stop before removing PPE or
setting tool down
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Summary
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Don’t take grinder safety for granted
Understand and respect the hazards
Before using a grinder, learn how to eliminate, reduce and protect
against letting those hazards result in injury
If observing others using a grinder, reinforce the appropriate
behaviors and coach for improvement on those at risk
Remember the close proximity rule – If you have employees
within 10 Ft of your grinding operation they must maintain the
same level of (eye / face ) protection.
Zero is our Goal! Everyday!
October 2012
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