Tool School: Cut, Grind And Polish With The Versatile Angle Grinder

Tool School: Cut, Grind And Polish With The Versatile Angle Grinder
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You won’t find a more versatile or unforgiving tool than the angle grinder. They’re loud and dangerous, but indispensable for jobs that can’t be done any other way.

Photos by KLINGSPOR Fiberscheibe, Charles & Hudson

Angle grinders work by spinning a small disc or wheel at a high rate of speed (from 8,000 to 11,000 RPM) to cut, grind or polish. They are available as corded, cordless or pneumatic (air powered).

Angle grinders are categorized by disc/wheel size and amperage. Disc sizes range throug 4, 4.5, 5, 6, 7, 9 and 12 inches, but for most DIYers the 4-4.5 inch range will suffice. At that size, you’ll be able to perform most general tasks and have a wide range of discs and wheels to choose from. An angle grinder in the 5-9 amp range will provide more than enough power for your cutting and grinding needs, and unless mobility is a top concern, stick to a corded model for the best value.

An apartment dweller may not find much use for an angle grinder. But if you’ve got a workshop and do any welding or light construction projects around your home, an angle grinder should be part of your arsenal. Here are the most common tasks that an angle grinder can accomplish.

Metal Cutting & Grinding

A metal cutoff wheel uses aluminium oxide as an abrasive to cut rebar, rusted bolts, and iron fencing. A metal grinding wheel is necessary to clean up welds.

Tile, Stone And Concrete Cutting

An angle grinder equipped with a dry cut diamond wheel can cut ceramic and masonry materials with ease. They work best for trimming tile or working in tight spots, as well as cutting in for outlets or plumbing fixtures.

Restoring Metal Edges

Shovels, hoes, and lawnmower blades, can be sharpened with an angle grinder fitted with a grinding wheel. You don’t need these tools to be sharp like a knife blade, you just need the edges restored to their original shape.

Grinding Mortar

The first step in tuckpointing brick is clearing out the old mortar. The best tool for that job is an angle grinder with a diamond tuckpointing wheel.

Polishing Aluminium

A polishing wheel or buffing pad will bring aluminium back to its shiny self. If the aluminium is really marked up you can start with a high grit grinding disc then move the the polishing wheel.

Remember: safety first! Always wear eye protection when using an angle grinder. Sparks, metal, abrasive debris, and stone are always thrown from the tool. Hearing protection is also recommended as is a face shield for some applications. For masonry work, always wear a dust mask.

Lifehacker’s Workshop column covers DIY tips, techniques and projects.


  • Got a 4 at home and a 6 and 9 at work. When you wear them down from a nine you put the disc on the six and then on my 4. Always got discs that are small

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