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How To Grind And Cut

One of the handiest tools in the farm shop is the angle grinder, but it can also be one of the most dangerous. Using the right disc and handling the grinder correctly will ensure it can be used quite safely. Here’s a look at how to get the most out of this handy tool.


First, make sure you’ve selected the proper disc for the job. There are a variety available and each one has a special application. Discs are specifically designed for use on a particular material such as masonry or ferrous metal, so be sure to check the label to make sure it works for what you need. Also, be sure the maximum RPM rating is equal to or greater than the grinder’s no-load speed.

The two most common discs are for grinding and cutting. They should never be used for anything other than what they were designed for. Using a thin cutting disc in a grinding application can cause it to shatter. Conversely, grinding discs should never be used for cutting.


If a disc does shatter, it will do a pretty good impersona- tion of a hand grenade, sending fragments flying. Fortunately, the consequences won’t be as severe. The lightweight pieces will probably just cause a nasty bruise or scrape. But shattering risk does make wearing eye protection essential. Tiny pieces of ground metal and sparks can easily strike you in the face, too, even during normal operation. Anyone who has used a grinder without a full-face shield will probably have felt pieces hit his face many times (I can vouch for that). So don’t risk it — wear adequate protective gear. That includes a full-face shield, leather gloves, ear protection and long sleeves.

And although the grinder’s safety shield can sometimes get in the way and make some jobs awkward, leave it in place. It’s there for a good reason. Also be careful about where sparks are directed. Hold the grinder so they won’t fly up in your face and won’t land in a pile of flammable material in some corner of the shop. As a general rule, be sure to remain in the shop for at least half an hour after doing anything that creates sparks. That will ensure the building won’t burn down while you’re in the house eating lunch.

Clamp the workpiece firmly in place so it won’t move. Don’t try to one-hand it — you need both hands on the grinder. If the workpiece moves with a cutting disc spinning inside the kerf, that could cause the disc to shatter.


When using a grinding disc, hold the grinder at about a 15 degree angle to the work surface. Move it slowly across the entire area to be ground down, working the entire surface evenly. Never gouge it into the metal. That can cause small metal fragments of the base metal to break off and become red-hot projectiles. And you don’t want to grind with the edge of the disc; that can cause it to shatter. But don’t hold it flat on the workpiece either. And don’t force it. The weight of the grinder and disc is adequate; you don’t need to push down on it.

The technique for using a cutoff disc is completely different. In this case you only want to use the edge of the disc to do the work. Again, don’t use force, just keep the disc solidly in contact with the metal. Let it chew through the material slowly.

Now, go out into the shop and build something!


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These photos demonstrate the correct way to hold an angle grinder when using cutting and grinding discs. Cut with the edge of a cutting disc and grind at a 15-degree angle to the work surface. Note that the workpieces are firmly clamped down to prevent movement.


If a disc does shatter, it will do a pretty good impersonation of a hand grenade, sending fragments flying. The lightweight pieces will probably just cause a nasty bruise or scrape

About the author


Scott Garvey

Scott Garvey is a freelance writer and video producer. He is also the former machinery editor at Grainews.



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