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Grinding disc buying guide

Updated: 21 October 2026

You already own an angle grinder, and the next amazon.co.uk search is full of discs that all claim to grind metal. This grinding disc buying guide tells you which wheel matches the guard before you look at stars. Check diameter, bore, thickness, grit, maximum speed and the date on the ring, and treat a 4.6 rating as the wrong job when the reviews say cutting. The [grinding discs comparison](/hub/sanders/grinding-discs) ranks three kept packs. This page is the checklist for any bonded wheel. Shelf prices are from amazon.co.uk on 19 October 2026. Peter F. did not run a lab test. A qualifying purchase can earn a commission at no extra cost to you.

You already own an angle grinder, and the next amazon.co.uk search is full of discs that all claim to grind metal. This grinding disc buying guide tells you which wheel matches the guard before you look at stars.

Our top picks

Merryland Merryland 125 mm grinding wheels (10)

Best overall

Merryland Merryland 125 mm grinding wheels (10)
4.5/10about £17.90
View offer
Merryland Merryland 115 mm grinding wheels (10)

Rank 2

Merryland Merryland 115 mm grinding wheels (10)
6.8/10about £15.90
View offer
Hilka Hilka Turbo Flex grinding discs (5)

Best value

Hilka Hilka Turbo Flex grinding discs (5)
5.5/10about £10.02
View offer
On this page
  1. 1.What you are actually putting on the spindle
  2. 2.Diameter, bore and thickness
  3. 3.Grit, speed and the use-by date
  4. 4.Where these three listings still fail the list

What you are actually putting on the spindle

A grinding disc for weld dressing is a thick, resin-bonded wheel with a depressed centre, often type 27, used on its face at a shallow angle. Cutwel describes that wheel at about 6–8 mm, and cutting discs at about 1–3 mm on the edge. The usual bore is 22.23 mm, so a 115 mm wheel and a 125 mm wheel can share a hole and still be unsafe on each other's guard. If the wheel stands proud, leave it in the box. Read the size line as diameter, then thickness, then bore: 115 x 6.0 x 22.23 mm is a grinding wheel, and 115 x 1.0 x 22.23 mm is a cutting wheel. EN 12413 is the bonded-abrasive standard FEPA names.

Diameter, bore and thickness

Match the guard first. A 115 mm disc belongs on a 115 mm grinder, and a 125 mm disc on a 125 mm grinder. Bore comes second. If the page does not print 22.23 mm, do not fill the gap from habit. About 6 mm on the face is the stock-removal band. A 1 mm disc in the same search is a cutting disc. FEPA's leaflet says you do not grind with a cutting wheel, because side load is not what that thin wheel is built for. That contrast is on grinding disc vs cutting disc.
Merryland Merryland 125 mm grinding wheels (10)

Testsieger

Merryland Merryland 125 mm grinding wheels (10)
4.5/10about £17.90
View offer

Grit, speed and the use-by date

Cutwel puts coarse aluminium oxide, roughly grit 24–36, in the usual band for removing steel. A code such as A30R-BF should agree with the grit number. If the two fields clash, you do not know which wheel will arrive. The rpm mark on the disc must be at least the grinder's rated speed. A slower disc is the wrong disc, even if the hole fits. HSE's HSG17 treats resin-bonded hand-held wheels as carrying about a three-year use-by date. No readable date on the ring is a reason to stop. At work, PUWER expects a guarded machine and people trained to mount wheels. Home use does not cancel either check.

Where these three listings still fail the list

Stars are a weak signal because the public files fail this checklist. The Merryland 115 mm ten-pack at £15.90 prints 13,300 rpm and A30R-BF, while the grit field says 46, and many of the 1,006 reviews say cutting disc. The 125 mm ten-pack at £17.90 prints 12,250 rpm and the same grade against a grit field of 60. The Hilka five-pack at £10.02 is grit 180, with no rpm or bore on the listing. Grit 180 is finer than weld dressing, and a stainless title is not an iron-free promise. Who should skip each pack is on best grinding discs. Mounting is on how to use a grinding disc.

Common questions

What thickness is a grinding disc?
For stock removal and weld dressing, plan on about 6 mm, inside the 6–8 mm band Cutwel describes. Cutting discs are about 1–3 mm and are used on the edge. Both Merryland listings print 6.0 mm. A review that describes a 3 mm disc is not confirming that specification.
Can I use a 125 mm disc on a 115 mm grinder?
No. The bore can be 22.23 mm on both sizes, and the hole is not the guard. A 125 mm wheel stands outside a 115 mm guard. Taking the guard off is the wrong fix. Buy the diameter printed on the grinder, then check the disc rpm is at least that machine's speed.
What grit removes weld metal?
Coarse aluminium oxide, roughly grit 24–36, is the usual band for removing steel. An A30 grade is a stock-removal code. Hilka's grit 180 is a finer finishing wheel if the ring matches the page. Where Merryland's grit field and A30R-BF line disagree, treat that clash as unresolved.
Do grinding discs expire?
Resin-bonded wheels for hand-held grinders carry about a three-year use-by date under HSE guidance in HSG17. Read the date on the ring, not the order date in your amazon.co.uk history. A disc past that date, or with no readable date, does not go on the spindle. A damp shed is a separate reason to reject a wheel.
Is a fine grit suitable for welds?
Grit 180 will touch a weld, but it is slow beside a coarse 24–36 wheel. Hilka prints grit 180, calls it medium, costs £10.02 for five discs, and does not print rpm. Use it for light finishing on a 115 mm grinder only after you read the ring. Heavy dressing needs a coarse grade whose fields agree.
Why do some grinding-wheel reviews say cutting?
Search and Best Sellers Rank often file these wheels under cut-off wheels, so reviewers describe the job they did. Merryland's 115 mm pack is 4.6 from 1,006 reviews, mixing grinding praise with cutting-disc wording. Read thickness with the review text. Stars are not proof the writer used a 6 mm face.
What rpm should a 115 mm or 125 mm disc show?
The mark on the disc must be at least the grinder's rated speed, and it is usually lower on the larger diameter. Merryland prints 13,300 rpm on the 115 mm pack and 12,250 rpm on the 125 mm pack. Hilka prints EN 12413 and no rpm. If the ring is slower than your grinder, that disc stays off.

Related pages

115 mm vs 125 mm grinding disc

Grinding discs

Best grinding discs: Merryland top pick for 115 mm

How to use a grinding disc: guard, flange and angle

Grinding disc versus cutting disc: face or thin edge

Sources

Sources taken from the research digest. Prices, stars and review counts are the stored amazon.co.uk listing figures.

  1. HSE HSG17 — safety in the use of abrasive wheels (retrieved 19.10.2026)
  2. HSE — PUWER overview (retrieved 19.10.2026)
  3. FEPA — safety leaflet, bonded abrasives (retrieved 19.10.2026)
  4. Cutwel — expert guide to grinding discs (retrieved 19.10.2026)
  5. Cutwel — Klingspor A 24 R grinding wheels (retrieved 19.10.2026)
  6. Abrasives Safety — reinforced bonded wheels (retrieved 19.10.2026)