What Are the Three Main Uses of an Angle Grinder?

The three jobs at a glance

An angle grinder is a handheld tool with a motor that spins a disc at high speed. A gearhead turns that spin through 90 degrees, so the disc sits at the front, ready to touch a surface. Swap the disc and you change what the tool does.

Nearly every task fits one of three groups. Here is how they compare.

Use 1: Cutting

Cutting is the job most people buy a grinder for. A thin abrasive cut-off wheel slices through bolts, threaded rod, conduit, pipe and thin steel faster than a hand hacksaw. A diamond blade does the same for tile, brick and concrete.

Compact grinders are popular for this because they fit into tight spaces. For example, the TEENO T-3608-WS is a 3 in cordless grinder with a listed top speed of 19,500 RPM, and its kit includes six 3 in discs. That mix covers metal cut-off, flap disc, plastic trim and tile detailing. The trade-off is that a small disc cuts shallower than a 4-1/2 in one.

If metal cutting is your main goal, our best angle grinder disc for cutting metal page compares options side by side.

How to cut metal with an angle grinder

Cutting metal is simple once you respect the disc. Cut-off wheels are thin and made to cut straight, not to bend or twist sideways.

• Clamp the workpiece firmly so it cannot shift or vibrate.
• Mark your cut line, then fit a cut-off wheel rated for metal. Check that its size and speed rating match your grinder.
• Fit the wheel guard and the side handle, and tighten the wheel securely.
• Let the disc reach full speed before it touches the metal.
• Guide the grinder along the line with light, steady pressure. Let the wheel do the cutting.
• Keep the wheel moving in line with the cut. Do not twist, lever or pry the wheel in the slot.
• Let the disc stop fully before you set the tool down.

Use 2: Grinding, shaping and sharpening

Grinding removes material to change a shape or smooth a surface. Common jobs include flattening a weld bead, rounding a sharp edge, removing burrs after a cut and shaping a bolt end so a nut threads on.

This is where thicker grinding wheels and flap discs come in. A grinding wheel removes material quickly. A flap disc is a bit gentler and leaves a smoother surface, which makes it a good choice for blending welds.

Sharpening also falls into this group. Garden tools, shovels and axes can be touched up with a grinder, and many people use one on mower blades. Keep the original edge angle and go slowly so the metal does not overheat. See our best angle grinder disc for sharpening mower blades page for disc options. Always remove the blade from the mower first, and disconnect the spark plug wire before you do.

Use 3: Cleaning and finishing surfaces

The third group is surface prep. A wire wheel or a strip disc can take off rust, scale, old paint and dried-on residue. A flap disc can smooth the surface afterward. With the right pad, a grinder can also sand or polish metal and some stone.

Many cordless kits include both cutting and grinding wheels, which is handy if you want a single box that covers the basics. The DEKOPRO kit, for instance, lists three cutting wheels and three grinding wheels along with a case and two guards.

Surface work tends to mean longer sessions, so weight matters. Weights on our best angle grinder cordless page run from 3.3 lb to 10.63 lb. A lighter tool and a side handle make it easier to keep control for long jobs.

Safety before you start

Angle grinders are fast and unforgiving. Treat every job as one where the disc could shatter or the tool could jump.

• Wear safety glasses or a face shield, plus hearing protection and gloves. Sparks and fragments fly in all directions.
• Wear a dust mask or respirator when you grind metal, paint, tile or masonry. The dust is not safe to breathe.
• Keep the guard on and use the side handle. Hold the tool with both hands.
• Check every disc for cracks or chips before use, and never use a disc past its rating.
• Keep sparks away from fuel, rags, solvents and other flammable items.
• Secure the work, and keep your body out of the line of the disc.
• Unplug a corded grinder or remove the battery before you change a disc.
• Kickback happens when a disc binds. Safety features such as a kickback brake or an electronic clutch can help stop the wheel if it binds. The DEWALT DCG413B and Milwaukee 2880-20 both list kickback protection.

Choosing a grinder for these jobs

For most home projects, a 4-1/2 in grinder is the usual size. It handles cutting, grinding and finishing without feeling too bulky. Smaller 3 in tools suit tight spaces, but they do less on thick stock.

Cordless models free you from the outlet and the cord, and brushless motors help with runtime. Check whether the grinder comes as a bare tool or as a kit. The DEWALT DCG413B, for example, is listed as tool only, with no battery or charger, while the FULLYEA FAG402-003 comes with two batteries, a charger and a case, and offers three speed settings up to 12,000 RPM.

If you want to compare more models, start with our best angle grinder page. If you already own batteries from one brand, our best cordless angle grinder page can help you narrow the field.

Frequently asked questions

Can one angle grinder do all three jobs?

Yes. The tool stays the same, and you only change the disc. Just make sure each disc is rated for the grinder's speed and arbor size.

Can I grind with a cut-off wheel?

No. Cut-off wheels are thin and built for straight cuts. Side pressure can make them break. Use a thicker grinding wheel or a flap disc for grinding.

What does an angle grinder grind most often?

Welds, rough edges, burrs and rust are the common targets. It is also used to touch up the edges of garden tools and mower blades.

Do I need a 4-1/2 in grinder or a 3 in one?

A 4-1/2 in grinder is the more versatile choice for general work. A 3 in grinder is better for tight spaces and light cutting.