Cutting wheel vs cutting disc
“Cutting wheel”, “cut-off wheel”, “cutting disc” and “cut-off disc” are, in everyday use, the same thing: a thin wheel for slicing material on an angle grinder or similar tool. Some sellers use “disc” for diamond or thinner versions and “wheel” for bonded abrasive ones, but there is no strict rule, so rely on the product description instead of the name.
What matters is how a cutting wheel differs from a grinding wheel. A cutting wheel is thin and designed to be loaded along its edge. A grinding wheel is thicker and made to handle face pressure. Using one for the other’s job is a common cause of wheel breakage. See grinder wheel types for the wider family.
Bonded abrasive vs diamond cutting wheels
Bonded abrasive wheels are made of abrasive grains held in a resin bond, often with fiber reinforcement. They wear away as they cut and are the usual choice for steel, stainless steel and other metals. They are inexpensive and available in many sizes, but they shrink in diameter as you use them.
Diamond cutting wheels have industrial diamond bonded to a metal or resin body. They are designed mainly for masonry, concrete, tile, brick and stone, and generally last much longer than a bonded wheel on those materials. They come in styles such as segmented, continuous rim and turbo, which trade off cutting speed, finish and dust. Some are rated for specific materials only, so do not assume a diamond blade is suitable for metal.
| Bonded abrasive | Diamond | |
|---|---|---|
| Typical use | Steel, stainless, other metals | Concrete, brick, tile, stone |
| Wear | Wears away as it cuts | Diamond segment wears slowly |
| Cost per wheel | Lower | Higher |
| Notes | Check material suitability | Match blade style to material |
Shape: Type 1 vs Type 27 cutting wheels
- Type 1 (flat): a flat wheel that offers maximum cutting depth and is the common shape for straight cuts. It is sometimes listed as Type 41 in related standards.
- Type 27 (depressed center): has a raised hub, which gives clearance for the nut and makes it easier to cut flush against a surface or at an angle. It is sometimes listed as Type 42.
Choose by the job. If you need depth to cut through bar, pipe or thick sections, flat is often preferred. If you need clearance or flush cuts, depressed center is often the more practical choice. The correct guard can depend on the wheel type, so follow your grinder’s manual.
Abrasive grain
- Aluminum oxide: economical and versatile, a common choice for general steel cutting.
- Zirconia alumina: tougher, often used for heavy-duty cutting of steel and structural metals.
- Ceramic alumina: a premium grain that tends to cut quickly and last longer, often chosen for stainless and hard metals.
- Silicon carbide: sharp, used for non-ferrous metals and masonry products.
Thickness and size
Cutting wheels come in different thicknesses, and common diameters follow common grinder sizes, such as 4-1/2 and 5 inch (115 and 125 mm), plus larger sizes for bigger grinders.
- Thin wheels cut faster with less effort and less heat and waste less material, though they can be more delicate.
- Thicker wheels last longer and tolerate rougher use, but cut more slowly and with more heat.
Always check the wheel’s maximum rated speed against your grinder’s speed, and make sure the diameter and arbor hole match your tool. See types of angle grinders for typical disc sizes.
Matching the wheel to the material
| Material | Often suitable |
|---|---|
| Mild steel, pipe, bar | Aluminum oxide or zirconia bonded wheel |
| Stainless steel | Wheel labeled for stainless (often low in iron, sulfur and chlorine); ceramic grain is common |
| Cast iron | Wheel labeled for cast iron or ferrous metals; some guides suggest silicon carbide |
| Aluminum and other non-ferrous | Wheel designed for non-ferrous metals, since ordinary wheels can load up |
| Brick, concrete, stone, tile | Diamond blade |
What cutting wheel should be used for cast iron?
Cast iron is hard and brittle. Many general metal cut-off wheels list cast iron on the label, and some guides suggest silicon carbide products for it. The safest approach is to read the wheel’s label or the manufacturer’s data sheet and choose a wheel that explicitly lists cast iron. For thick or heavy cast iron, a different tool may be more appropriate.
Using cutting wheels safely
Cut-off wheels can break violently if misused, so:
- Wear eye or face protection, hearing protection, gloves and suitable clothing, and keep the guard in place.
- Do not use a cutting wheel for side grinding or apply sideways pressure.
- Secure the workpiece, let the wheel reach full speed, and keep the cut straight without twisting or forcing the wheel.
- Inspect the wheel before use and discard any that is cracked, chipped or damaged, or past an expiry date if one is printed.
- Do not use a wheel on a grinder that spins faster than the wheel’s rating.
- Cutting masonry produces silica dust, so use suitable dust control and respiratory protection.
Follow the wheel manufacturer’s instructions and local safety rules.
FAQ
What is the difference between a cutting wheel and a cutting disc? In practice, none. Both terms refer to thin wheels for cutting on an angle grinder.
What are the different types of grinding wheels? They include grinding wheels, flap discs, wire wheels, diamond wheels and polishing pads. Our grinder wheel types guide covers them.
What are the key differences between Type 1 and Type 27 cut-off wheels? Type 1 is flat and gives maximum cutting depth. Type 27 has a depressed center for clearance and flush cutting.
What type of cutting wheel should be used for cast iron? Use a wheel labeled as suitable for cast iron or ferrous metals, as described above.