Grinding Wheel Safety Poster-bonded 5m2eh

Grinding wheels are safe and necessary cutting tools, but it must be ed that they are not unbreakable.To prevent breakage, it is important to follow safe practices and tips given in this guide for the safe use of grinding wheels.

 Select correct wheel for your operation. " Do Ring test" and inspect for cracks. Never use cracked wheel.  Never exceed maximum safe speed established for wheel. Be sure machine speed is not excessive.  Never alter hole in wheel or force wheel on spindle.  Use clean, recessed, matching flanges at least 1/3 wheel diameter.  Use one clean, smooth blotter on each side of wheel under each flange. Order of Tightening  Tighten nut only enough to hold wheel firmly. 1-2-3-4-5-6-7-8  Adjust wheel guard and put on safety glasses before starting wheel.

 Use of flanges of uneven or too small What are some of the most diameter. common errors in mounting  Use of washers instead of flanges. which can cause trouble?  Flanges without proper clearance or relief.  Excessive tightening causing flanges to bend.  Bolts should be tightened with torque wrenches.  Failure to clean all dirt and foreign material from sides of wheels and flanges.  Follow tightening sequence of bolts.  Forcing a wheel onto an arbor where fit is  Avoid over tightening or loose tight. clamping.  Over tightening: Induces stress in the  Use of just any loose washers or bushings to wheels and can cause accidents. try to make a wheel fit a machine.  Loose clamping: Wheel can slip.  Failure to use blotters on wheels.  Regularly check flanges for flatness, nicks and gouges, etc.

 Adjust the dust hood and coolant nozzle (for wet grinding). Keep work rest adjusted within 1/8" of wheel face (periphery).  Stand aside and allow wheel to run idle a full minute before starting to grind.  Dress wheel if out of true.  Make grinding without "bumping" or impact.  Grind only on face of straight wheel. Use disc wheels for side-grinding. Light side-grinding permissible on cup or saucer wheel.  Never force grinding so that motor slows noticeably or work gets hot.  Protect wheel when not in use. Store safely if removed from grinding machine.

What is RPM & MOS : REVOLUTIONS PER MINUTE (RPM): is the number of complete axis turns per minute. MAXIMUM OPERATING SPEED (MOS) is permissible operating speed of grinding wheel. Wheel Operating speed in meter/second = 3.142 x D x N 60,000 D: Diameter in MM N: Machine spindle RPM

Is Grinding Wheel a dangerous tool ?

No - if the wheel is properly mounted and not abused, it is not dangerous. Today, grinding is not considered a dangerous occupation.

What causes Grinding Wheel accidents ?

YES - definitely. Normally grinding wheels run at peripheral speed of 33 - 60 meters/second, which is same as 120 - 216 kms/hour. At such high speeds, if wheel breaks, it might cause serious personal injury or damage to machine or equipment.

Are all grinding wheels No - All grinding wheels The most common causes equally strong ? are breakable.Vitrified are: wheel is similar to glass  Using the wrong and can break easily. wheel for the job Careless handling can  Careless handling. easily damage all types of  Improper mounting grinding wheels.  Exceeding maximum operating speed  Excessive pressure

Why can't we use only the strong, tough wheels which can not be broken easily ?

How can I be sure that a wheel given to me from the Store room has not been damaged before I get it ?

Can grinding accidents be serious ?

The tough, strong wheels would not be suitable for all kinds of grinding. On some classes of grinding, relatively soft wheels are necessary to prevent burning and spoiling sensitive and expensive steels.

Inspect it very carefully for cracks or any marks that look as though the wheel might have been damaged. Even if no cracks are visible, give the wheel a "ring test." If it gives a clear ring, then mount the wheel on machine. Do not use wheels with a dull sound. Check wheel spindle condition - Excessive hot machine and spindle can break the wheel in multiple pieces.

How can a wheel be damaged by handling ?

Is it dangerous to use heavy pressure ?

All wheels are breakable.Vitrified wheels are very similar to a piece of glass. Resinoid and Rubber wheels can usually stand more abuse, but they can be broken.  Prevent dropping, mishandling and impact on the wheel  Prevent from moisture, water and direct heat  Avoid trans-shipment to reduce frequent handling and chances of damages.  Avoid rolling of grinding wheel on the floor from storage to point of use.

 Side pressure on thin straight wheels is dangerous. Most wheels will stand quite a lot of straight radial pressure, but there is a limit to what they can take.  Sudden bumping or pounding is more dangerous than steady, even pressure.

While starting the machine stand to one side of the wheel for at least a minute before starting to grind. If it is portable machine, hold it under a bench or inside a heavy casting for a minute or so.

If grinding is not dangerous, why use a guard or other protective device on every grinding wheel ?

Guards and other protection devices make grinding really safe. Breakages do not occur often, but because of the high speed at which grinding wheels travel, the results are apt to be serious unless proper guards are in place.

Why should I wear goggles if my machine is properly guarded ?

A guard can't possibly keep in all the small particles of grit and steel which are loosened during any grinding job. It doesn't take a big particle to do a lot of damage to an eye. Goggles are the best protection against this.

For any other abrasive safety information, refer IS, ANSI or OSHA standards. Or Product Engineering Department, Grindwell Norton Limited, Mora-Uran - 400 704. Dist. Raigad. Maharashtra