What Is a Cut Off Wheel and What Is It Used For?
A cut off wheel is a thin, flat abrasive disc that mounts on an angle grinder and slices through metal instead of grinding it down. The grinder supplies the power and the wheel does the cutting, so they are two parts of one setup, not rival tools. People use them for steel, pipe, rebar, angle iron and sheet metal.
DEWALT DW8062B5Best overall
EZARC 80711502Thinnest listed wheel
VOISEN 100 Pack Cut Off Wheels 4 1/2 inchClear RPM rating, big packWhat a cut off wheel actually is
A cut off wheel (also called a cutting wheel or cut-off disc) is a thin disc made to cut through a workpiece. The name describes the job: you use it to cut a piece off a bar, pipe or sheet. It is not meant for shaping or smoothing, which is what thicker grinding wheels do.
Most cut off wheels are bonded abrasives. Tiny hard grains, often aluminum oxide, are held together with resin, and a layer or two of fiberglass mesh adds strength. As you cut, the grains wear away and fresh ones are exposed, so the wheel slowly gets smaller. Diamond wheels work differently. They have a solid steel body with diamond material on the edge, so they keep their diameter.
Thinness is the main design feature. A thin wheel removes less metal as it cuts, which usually means a faster, cleaner cut with fewer burrs. On our best cut off wheels page, the listed thicknesses run from 1 mm to 1.2 mm.
What a cut off wheel is used for
The short version: straight cuts in metal. Because the wheel is thin and spins fast, it can part material that a hand saw would take a long time to get through.
Common jobs include:
- Cutting steel bar, angle iron and tubing to length
- Trimming pipe and rebar
- Cutting sheet metal and stainless steel
- Removing rusted bolts, hinges or fasteners
- Cutting cast iron or aluminum, when the wheel lists those metals
- Cutting tile or stone, but only with a wheel that names those materials
Cut off wheel vs grinder
Searchers often type "cut off wheel vs grinder," but this is not really a choice between two competing tools. The angle grinder is the power tool. It holds a motor, a guard and a spinning spindle. The wheel is an accessory you attach to that spindle.
The same grinder can do different jobs depending on what you put on it. A cut off wheel makes it a cutting tool. A thick grinding wheel makes it a material-removal tool. A flap disc or wire wheel makes it a finishing or cleaning tool.
If you are choosing what to buy, think of it this way: the grinder is the long-term purchase, and the cut off wheel is the part you replace. Bonded wheels wear down with use, so many people keep a pack on hand. If you want to compare options, our best cut off wheels page lines up size, thickness, pack count and listed metals on one sheet.
One more point: a cut off wheel is built to take force along its edge, not from the side. Using it like a grinding wheel can damage it, so keep to straight cuts.
Arbor and mandrel: what the terms mean
The arbor is the center hole of the wheel. It slides onto the grinder's spindle and is held by the flange and nut. Arbor size must match your grinder. The 4-1/2 inch wheels on our comparison page list a 7/8 in arbor, which is a common size for that diameter.
A mandrel is a different part. It is a small shaft that holds a wheel so it can be used in a rotary tool or die grinder. If you have heard "cut off wheel mandrel," it usually refers to the screw-in holder used with small wheels on those tools. On a standard angle grinder you normally do not need a mandrel, because the spindle, flange and nut do that job.
So when you shop, check two things: the wheel diameter fits your grinder's guard, and the arbor hole fits the spindle. A wheel that does not match either should not be used.
Bonded wheels vs diamond wheels
The two main types behave differently. Bonded wheels are consumable and come in larger packs. Diamond wheels cost more effort to compare because makers describe their lifespan in claims, not in verified results, but they keep their size as you cut.
The table below uses figures from the product data on our comparison page.
| Feature | Bonded wheel (example) | Diamond wheel (example) |
|---|---|---|
| Product | DEWALT DW8062B5 | EZARC 4-1/2 in |
| Diameter | 4-1/2 in | 4 1/2 in |
| Thickness | 1.14 mm | 1 mm |
| Pack count | 5 | 2 |
| Body or reinforcement | Two sheets of fiberglass | Solid steel body |
| Arbor | 7/8 in | 7/8 in |
| Cut life | 50% longer life (claimed) | 5,000+ cuts on rebar, steel, iron and INOX (claimed) |
How to use a cut off wheel safely
Cut off wheels spin fast and can break if misused. A few habits reduce the risk a lot.
Follow these steps each time:
- Check that the wheel's max RPM is at or above your grinder's no-load speed. Only some makers publish this number, so look at the wheel label.
- Inspect the wheel for cracks, chips or damage before mounting it. Do not use a damaged wheel.
- Unplug the grinder or remove the battery before changing the wheel.
- Keep the guard in place and clamp the workpiece so it cannot move.
- Let the grinder reach full speed before it touches the metal, then use light, steady pressure.
- Cut straight. Do not twist, pry or bend the wheel in the cut, and do not use the side of the wheel.
- Wear safety glasses, a face shield, hearing protection, gloves and a dust mask. Sparks and fine metal dust are normal.
- Keep sparks away from flammable materials, and let cut pieces cool before touching them.
How to choose the right wheel
Start with size. Match the wheel diameter to your grinder and confirm the arbor. Then check thickness, since thinner wheels cut faster and remove less metal. Thickness is only listed for 18 of the 24 products on our page, so compare it where makers publish it.
Next, match the wheel to the material. Most bonded wheels list steel and stainless steel, while some diamond options also list aluminum, cast iron or tile. Always read the metals listed for the specific product.
Finally, think about how much you will cut. Packs on our page run from 2 wheels to 200. A big pack suits regular use of bonded wheels. A small pack of diamond wheels can be enough, since they do not wear down in diameter. You can see the full range, including picks for pack size and RPM ratings, on our best cut off wheels comparison.
Frequently asked questions
Can I cut wood or plastic with a metal cut off wheel?
No. Metal cut off wheels are made for metal. Using one on wood can cause kickback or burning, so use a wheel or blade made for the material.
Do I need a special grinder for a cut off wheel?
No, a standard angle grinder works if the wheel diameter, arbor size and RPM rating match it. Always keep the guard in place.
Why is a thin wheel better for cutting?
A thin wheel removes less material as it passes through the metal, so it generally cuts faster with less effort and fewer burrs.
How do I know when to replace a bonded wheel?
Replace it when it is cracked, chipped or worn too small to reach your cut comfortably with the guard in place. Never keep using a damaged wheel.