Abrasive wheel safety:Safety warning via angle grinder guards and brake discs

A Queensland worker suffered fatal injuries while operating a 230 mm (9 inch) angle grinder.

When a ruptured abrasive wheel hits the worker’s chest, the worker is killed. It seems that due to the strong impact of the projectile, it caused fatal internal damage.

In another incident, the abrasive wheel was stuck and the angle kicker kicked back and cut the worker’s wrist.

One of the main factors contributing to these accidents of abrasive wheel safety was the use of abrasive wheels that were too large for angle grinders, in some cases the shrouds had been removed and the grinders were fitted with 14 inch grinding wheel.

Cutting discs are usually designed for maximum outer edge speed (ie peripheral speed) of approximately 70 m/s (250 km / h), while larger angle grinders are manufactured with smaller revolutions per minute (RPM) speed Therefore, the edge speed of the abrasive wheel is always maintained at around 70 m / s.

Mounting a 14-inch (356 mm) cut-off disc to a 9-inch (230 mm) angle grinder will increase the edge speed to at least 120 m / s (430 km / h). Discs are not designed to increase speed. If you use a abrasive wheel, it can cause the abrasive wheel to shatter and hit the user and others.

A protective cover should be provided on all power tools and a protective cover should be used on all power tools that may cause the abrasive wheel to eject, disintegrate or cut the worker. If the guard is removed, nothing prevents the broken debris from hitting the user. When the user’s hand puts the angle grinder down and the weight of the grinder is placed directly on the abrasive wheel, the blade is more likely to approach the unprotected moving blade and the risk of blade damage is greater.

Another factor that increases the risk of disk failure is when the center disk hole size is too large for the spindle flange on the angle grinder. As the diameter of the abrasive wheel increases, the size of the hole also increases.

If the abrasive wheel hole is too large for the spindle flange, the abrasive wheels may be off center, become unbalanced, excessively vibrate and quickly cause it to break.

Therefore, the abrasive wheel training courses has taken some recommended measures:

Use the angle grinder with the correct shield supplied by the abrasive manufacturer.
Install a properly sized abrasive wheel with a hole that matches the spindle flange.
Use the tightening tool provided by the bench grinder wheels suppliers to tighten the abrasive wheels. Using other equipment (such as punchers and hammers) can damage abrasive wheels and grinders.
Hold the angle grinder with both hands and make sure that the side handles are inserted into the side of the device for optimal grip.
Grinding using a grinding wheel. Grinding with a abrasive wheel can damage the abrasive wheel and increase the likelihood of abrasive wheel breakage during use.
Make sure that the maximum RPM abrasive wheel marked on the abrasive wheel is at a higher speed than the angle grinder.
Be sure to throw away the damaged abrasive wheel and do not reuse it.
Allow the grinding machine to run before cutting or grinding.
Chooes abrasive wheel certificate.

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