Metal cutting discs: choosing the thickness and diameter
To cut metal, choose a disc with the same diameter and the same bore as your machine, then decide the thickness according to the workpiece: a thin disc (1.0-1.6 mm) cuts sheet, thin tube and stainless steel quickly and cleanly; a thicker one (2.0-3.0 mm) copes better with sections, rebar and site cutting. In the collection the diameters range from 75 to 355 mm and the thicknesses from 1.0 to 3.0 mm. For stainless steel and aluminium there are dedicated discs.
The types
- Flat discs (type 41): they are thin and work edge-on, perpendicular to the workpiece. They are the classic cutting disc, for angle grinders and chop saws. One example is the Fervi MTP4115/1.0, 115 mm and 1.0 mm.
- Depressed-centre discs: they have a recessed centre, useful for cuts close to a wall or a surface.
- Thin discs for stainless steel: thicknesses from 1.0 to 1.6 mm, with an abrasive formulated for stainless steel, which overheats easily.
- Discs for chop saws: large diameters (350-355 mm) for cutting sections and tubes in steel fabrication.
- Discs for aluminium: formulated so as not to clog with the soft metal.
- Mini discs: 75 mm, for small grinders and for work in tight spaces, such as the Fervi MTP4075/1.5.
How to choose by job
| Use | Recommended type | Why |
|---|---|---|
| Sheet, thin tube, stainless steel | Thin disc 1.0-1.6 mm | Less friction and less heat, a more precise cut. |
| Rebar and sections on site | Disc of 2.0-3.0 mm, 125-230 mm diameter | Withstands thicker workpieces and accidental twisting. |
| Steel fabrication with a chop saw | Large disc 350-355 mm | Cuts sections and solid bar in a single pass. |
| Stainless steel in the workshop | Disc dedicated to stainless steel | Avoids contamination and discolouration of the cut. |
| Tight spaces | 75 mm mini disc | The small machine goes where the large one cannot reach. |
| Occasional use | Pack of 1 or 10 pieces | Discs have an expiry date: it is not worth buying more than you use. |
The features to look at
- Diameter: 115, 125, 180, 230 mm for angle grinders, 350-355 mm for chop saws, 75 mm for mini grinders. It must match the machine and the guard.
- Thickness: from 1.0 to 3.0 mm. The thin disc cuts with less effort and less waste, the thick disc lasts longer and copes better with heavy cuts.
- Bore: 22.23 mm in most cases, with some 25.4 mm or 10 mm sizes. If it does not match the spindle, do not fit the disc.
- Abrasive material: corundum and aluminium oxide are the most common; on the data sheet you will also find the indication for steel, stainless steel or aluminium.
- Grit and hardness: codes such as A30, A36, A46, A60 and the letters T or S indicate the type of abrasive, the grit and the hardness of the bond. If you are not familiar with them, choose the disc according to the metal stated on the data sheet.
- Type: 41 indicates the flat disc; on the data sheet you will also find depressed-centre discs.
- Pack: from 1 piece up to 150, depending on consumption. On site you take the box, in maintenance the single piece.
Common mistakes
- Using the cutting disc for grinding. It is thin and not made to work on its side: it can break.
- Cutting with the disc tilted. Keep it perpendicular to the workpiece and clamp the workpiece in a vice.
- Using a steel disc on stainless steel. Stainless steel needs a dedicated disc.
- Ignoring rpm and expiry date. The maximum rpm is printed on the disc; expired or chipped discs must be discarded.
- Forgetting the guard and protection. Guard always fitted, goggles or visor and gloves always worn.
Frequently asked questions
What thickness do I need to cut stainless steel?
A thin disc, between 1.0 and 1.6 mm, formulated for stainless steel. It cuts more cleanly and heats up less than a thick disc.
Can a cutting disc be used for grinding?
No. The cutting disc works edge-on, whereas the grinding disc is thicker and works flat. To grind, use a grinding disc.
Why do discs have an expiry date?
Because the resin bond ages over time and the disc can lose strength. Check the printed date and do not use expired discs.
Can I fit a 230 disc on a 125 grinder?
No. The diameter must be the one the machine and its guard are designed for.
You will find all the models in the Metal Cutting Discs collection: to choose the right thickness and diameter, ask the AMES technicians for a quote or advice.
More articles on this topic
Need this equipment?
The AMES catalogue lists more than 40,000 professional items, and if you are not sure where to start we will help you choose. Ask for a no-obligation quote or browse the rental fleet.