Excerpt:
Introduction
Grinding – shaping material by bringing it into contact with
a rotating abrasive wheel or disc. They can be portable grinders or fixed bench
grinders. It’s a safe job if you follow the rules. If you ignore safety or
ignore proper grinding procedures it can be an extremely hazardous job. You’re
the only person who can make it a safe job. Always follow your company’s
operating instructions and of course the manufacturer’s recommendations for
safely operating the equipment abrasive wheels, and discs. We don’t intend to
cover all the safety rules associated with grinding we just want to provide
some information to make you more aware of safety when operating grinders.
Common Errors
An abrasive disc is made of bonded abrasive with inserted
nuts or washes projecting studs, or tapped plate holes on one side of the disc
which is mounted on the machine face plate of a grinding machine. Only the
exposed flat side of an abrasive disc is designed for grinding. An abrasive
cutting wheel is designed to be mounted either directly, or with adaptors, or
on the spindle or arbor of a grinding machine. Only the periphery or
circumference of an abrasive cutting wheel is designed for grinding. Some of
the causes of personal injury involving abrasive wheels and disc include:
- Failure to use eye and face protection in addition to the
eye shield mounted on the grinder.
- Holding the work incorrectly.
- On bench grinders, not using the tool rest properly, or not
maintaining proper adjustment of the tool rest.
- Using the wrong type of wheel or disc, or a poorly
maintained 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 the
wheel or disc.
Certainly there are many more practices that can cause
injuries, but this list points out the need for proper training using
serviceable equipment, and following your company’s policies and procedures. If
you’re not sure about something check with your supervisor.
Safety Tips
Okay, a few safety tips before we get into the good stuff. Although portable grinding operators don’t usually worry
about the air supply of the compressor, it is extremely important that you have
the correct pressure, usually about 90 pounds for maximum performance.
- It’s a good idea to check the air pressure available at the
tool, 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 fittings
to keep the pressure at maximum throughout the entire line
- When connecting the grinding tool to the air hose clean off
any dirt and grit on the connecting nipple.
- Activate the air to blow out any moisture or dirt inside the
hose.
- When changing tools always use the valve to shut off the air
pressure, never kink the hose to cut off the air.
There’s no need to take chances. Go ahead and do it right
the first time.
Abrasive Wheels
Before we review how to check your grinding tools let’s take
a minute on abrasive wheels. These wheels are a very important part of the
safety effort. Wheels should be stored according to type, size, and speed with
all 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 wheel
or disc can create problems when the wheel is used. The blotter on every
grinding wheel provides the manufacturer’s recommended maximum operating speed.
Use the wheel equal to or greater than the grinding tool rated speed. Never use
a wheel with a missing blotter. We can’t overemphasize the fact that abrasive
wheels are extremely important, and must be properly stored, handled, and used
according to your company’s procedures and the manufacturer’s recommendations.
