When and how to use a rotary grinder

A look at when and how to use a rotary grinder correctly.

When used correctly, power tools can simplify even the most difficult of jobs. Unfortunately, many people often attempt to use powerful and even dangerous equipment without a full understanding of what it's true purpose is or even how to use it properly. Misuse of power tools can lead to injury or worse... and no one wants to get hurt simply because of a lack of knowledge.

A rotary grinder is a machine that uses a motor (usually electric) to spin a wheel at high speeds. The wheel is often made of hard materials covered with a rough grit much like sandpaper, though wheels of wire bristles are also sometimes used. The wheel is used to grind edges of metal and other hard surfaces for a variety of purposes, from sharpening to removal of slivers or rough edges.

One of the biggest problems that people have with rotary grinders is that they aren't used to using the grinding wheel and are unprepared for the pull of the wheel as it spins round. The wheel of a rotary grinder can spin at over a thousand revolutions per minute (rpm), and the natural reaction of any material that comes in contact with the wheel at that speed is to be thrown or pulled downward by the force of the wheel. Any item put on the grinder needs to be held firmly so as to prevent it from pulling or slipping loose (and potentially being thrown forcefully through the air where it could be a danger to those nearby.) Small materials should rarely be used with a large rotary grinder, as it's too easy for them to be pulled loose from the hand... if there are no other options, secure the piece with a clamp or vise grip pliers before grinding. If possible, use a smaller grinder for this, or one with variable speeds that has been set at a lower setting (as lower speeds produce less force and are less likely to pull a piece of material free from your grip. This will slow down the grinding process, however.)

In addition to the potential for thrown objects, other dangers exist when using a rotary grinder. A large amount of sparks are usually given off by the wheel and the material being used upon it, creating an opportunity for both burns eye injury in addition to the danger of fire. Loose sleeves, ties, or dangling jewelry can get tangled up in the machinery, pulling it (and the wearer) into the wheel. Other dangers include hearing damage from the loud grinding of objects on the wheel as well as the potential for exposed skin (especially on the hands) to come in contact with the grinding wheel, potentially causing serious abrasions. Safety goggles and earplugs should be worn, as well as gloves made of fire-resistant materials. You should also never operate a rotary grinder near any fuels or flammable materials. Should an accident occur with the grinder, unplug it or shut it down and seek medical help.

In the end, power tools are nothing more than that... tools. They can be used to make a difficult job easier, or through misuse can make a simple job much more difficult. Always remember the correct way to use them, and the chance of encountering serious problems will be much lower. Be careful, be safe, and best of luck.

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