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Cutting and Grinding Discs: Which Disc for Which Job
Short answer: abrasive discs for steel, diamond discs for masonry — and never the other way round. Cutting discs are thin and cut on the edge; grinding discs are thick and work on the face. Using the wrong disc, or the wrong face of the right disc, is how most angle grinder accidents happen.
The types, and what each one is for
| Disc | Use it on | Notes |
|---|---|---|
| Abrasive cutting disc | Steel bar, box bar, rod, sheet | Thin — cut on the edge only |
| Abrasive grinding disc | Welds, cut edges, rust on steel | Thick, depressed centre — work on the face |
| Diamond wheel | Tile, concrete, brick, stone | Abrades rather than cuts — let it work at its own pace |
| Turbo diamond wheel | The same, faster | Segmented rim: quicker cut, rougher edge |
| Tile wheel | Ceramic and porcelain tile | Finer rim, chips the glaze less |
All of these are stocked in Hand Tools & Accessories, including S-Lon cutting and grinding discs and Würth diamond wheels.
Sizes
Four inch and four and a half inch cover almost every site and workshop grinder. Check that the disc matches your machine — a disc too large for the guard is dangerous, and the guard is there for a reason.
How to cut tile without chipping it
- Mark the line on the glaze.
- Score a shallow pass first.
- Take the full depth on a second pass.
- On porcelain, cut from the back where you can.
Let the wheel cool between cuts. Holding a diamond wheel in one spot glazes the rim and it stops cutting.
How to cut steel cleanly
- Let the disc reach full speed before it touches the work.
- Do not lean on it. Forcing a cutting disc bends it, and a bent thin disc is the one that shatters.
- Stand out of the plane of rotation, so that if the disc does break, the pieces do not come at you.
Safety, in short
- Goggles, every time. Sparks, disc fragments and wire brush wires all go for the eyes. We stock Würth safety goggles.
- Guard on. Taking the guard off is the single most common cause of serious grinder injury.
- Check the disc before fitting. Chipped, cracked, or previously dropped — it goes in the bin.
- Respect the expiry date printed on abrasive discs. The bond degrades with age.
- Dust from tile and concrete is fine and sharp. Wear a mask.
Related
If you are cutting steel section, our guide to box bar sizes and gauges covers which gauge to buy and how to stop it rusting once it is cut and welded.
Common questions
Can I use a diamond wheel to cut steel?
No. Diamond wheels are made for masonry. Cutting steel with one destroys the rim and is dangerous. Use an abrasive cutting disc for steel.
What is the difference between a cutting disc and a grinding disc?
A cutting disc is thin and cuts on its edge. A grinding disc is thick with a depressed centre and works on its face. Neither should be used the other way round.
What size angle grinder disc do I need?
Four inch and four and a half inch fit the common small grinders and cover almost all site and workshop work. Never fit a disc larger than the machine and its guard are rated for.
Why has my diamond wheel stopped cutting?
The rim has glazed over, usually from too much pressure or from being held in one spot. Running it briefly through a soft abrasive material re-exposes the diamonds.
Need help choosing? Call +94 71 302 4843, message us on WhatsApp, or send your list through Request a Quote. WPL Trading, No. 305, Kandy Road, Dummaladeniya, Warakapola — open every day, 9.00 a.m. to 6.30 p.m., with island-wide delivery.
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