G for Grinding

This month we focus on grinding safety. Our definition of grinding includes high speed dry bench grinders, low speed wet grinders, belt linishers and disc grinders.

Nearly half of all accidents involving abrasive wheels are due to an unsafe system of work or operator error. Particular injuries result from wheel breakage or contact with a running wheel. As a first-aider I remember attending a colleague with a broken leg after a grinder wheel had parted at speed and a portion had hit him on the shin.

Even if we use other methods for sharpening our turning tools we will invariably use a bench grinder for some jobs e.g. sharpening drill bits.

• The principal safety critical aspect of using a bench grinder is to ensure that the grinding wheels are correctly mounted on the grinder and matched to it.

• Grinding wheels should be rated for at least the operating speed of the grinder, the type of wheel bonding should be suitable for the material being ground and grit size should be optimised for desired metal removal rates and required finish.

• One way of checking the integrity of a grinding wheel is that a sound wheel will ring when tapped whereas a cracked wheel will sound dull.

• Do not be tempted to grind using the side of a grinding wheel on a bench grinder - even though it will produce that straight grind that you want, the wheel is not designed to take the forces generated from grinding on the side of the wheel and can easily shatter.

• Grinding can produce significant quantities of dust and eye protection should be worn at any time when grinding. Wrap around specs or goggles are preferable and should be impact resistant.

The sparks produced from grinding are easily capable of causing a fire - a stream of sparks when grinding metal created a big hole in one of my favourite sweaters.

The action of grinding can produce considerable heat in an item being sharpened and care is required to avoid burns when handling tools.

LEARNING POINT  - Careful use of grinding equipment is essential to avoid harm

  to you, your friends or your workshop.

 Trevor Branton