Grinding – shaping material by bringing it into contact witha rotating abrasive wheel or disc. They can be portable grinders or fixed benchgrinders. It’s a safe job if you follow the rules. If you ignore safety orignore proper grinding procedures it can be an extremely hazardous job. You’rethe only person who can make it a safe job. Always follow your company’soperating instructions and of course the manufacturer’s recommendations forsafely operating the equipment abrasive wheels, and discs. We don’t intend tocover all the safety rules associated with grinding we just want to providesome information to make you more aware of safety when operating grinders.
An abrasive disc is made of bonded abrasive with insertednuts or washes projecting studs, or tapped plate holes on one side of the discwhich is mounted on the machine face plate of a grinding machine. Only theexposed flat side of an abrasive disc is designed for grinding. An abrasivecutting wheel is designed to be mounted either directly, or with adaptors, oron the spindle or arbor of a grinding machine. Only the periphery orcircumference of an abrasive cutting wheel is designed for grinding. Some ofthe causes of personal injury involving abrasive wheels and disc include:
- Failure to use eye and face protection in addition to theeye shield mounted on the grinder.
- Holding the work incorrectly.
- On bench grinders, not using the tool rest properly, or notmaintaining proper adjustment of the tool rest.
- Using the wrong type of wheel or disc, or a poorlymaintained or imbalanced wheel or disc.
- Grinding on the side of the cutting wheel.
- Taking too heavy a cut. Grinding must be done smoothly.
- Applying work too quickly to a cold wheel or disc.
- Grinding too high above the center of the wheel.
- Failure to use wheel washers or blotters.
- Vibration and excessive speed which lead to bursting of thewheel or disc.
Certainly there are many more practices that can causeinjuries, but this list points out the need for proper training usingserviceable equipment, and following your company’s policies and procedures. Ifyou’re not sure about something check with your supervisor.
Okay, a few safety tips before we get into the good stuff. Although portable grinding operators don’t usually worryabout the air supply of the compressor, it is extremely important that you havethe correct pressure, usually about 90 pounds for maximum performance.
- It’s a good idea to check the air pressure available at thetool, when the tool is running.
- Air hoses need to be inspected every day. Damaged, cut,frayed, or unserviceable air hoses must be repaired when they are detected.
- Be sure to use only the proper sized locking hose fittingsto keep the pressure at maximum throughout the entire line
- When connecting the grinding tool to the air hose clean offany dirt and grit on the connecting nipple.
- Activate the air to blow out any moisture or dirt inside thehose.
- When changing tools always use the valve to shut off the airpressure, never kink the hose to cut off the air.
There’s no need to take chances. Go ahead and do it rightthe first time.
Before we review how to check your grinding tools let’s takea minute on abrasive wheels. These wheels are a very important part of thesafety effort. Wheels should be stored according to type, size, and speed withall bins clearly marked. Proper storage of all wheels is extremely important.Never drop or bump an abrasive wheel or disc. The smallest crack in your wheelor disc can create problems when the wheel is used. The blotter on everygrinding wheel provides the manufacturer’s recommended maximum operating speed.Use the wheel equal to or greater than the grinding tool rated speed. Never usea wheel with a missing blotter. We can’t overemphasize the fact that abrasivewheels are extremely important, and must be properly stored, handled, and usedaccording to your company’s procedures and the manufacturer’s recommendations.