Independent comparisons. We may earn from shop links. More info

115 mm or 125 mm cutting disc

Updated: 21 October 2026

A 115 mm or 125 mm cutting disc is a guard decision. A 22.23 mm bore in a 125 mm title does not mean a 115 mm grinder can take that wheel. The bore often matches both sizes. The guard is tied to 115 mm or 125 mm. The [125 mm metal cutting disc comparison](/hub/sanders/cutting-disc-125-metal) lists only 125 mm products. Peter F. read the listing text and HSE guarding guidance on 19 October 2026. There was no measured guard test. A qualifying purchase can earn a commission at no extra cost to you. If the guard says 115 mm or 4.5 inch, buy 115 mm discs. If it is a 125 mm machine, the nine listings apply.

A 115 mm or 125 mm cutting disc is a guard decision. A 22.23 mm bore in a 125 mm title does not mean a 115 mm grinder can take that wheel. The bore often matches both sizes. The guard is tied to 115 mm or 125 mm.

Our top picks

HAUTMEC HAUTMEC HT0431 discs (10)

Best overall

HAUTMEC HAUTMEC HT0431 discs (10)
7.2/10about £10.99
View offer
DeWalt DeWalt DT42340TZ stainless discs

Rank 2

DeWalt DeWalt DT42340TZ stainless discs
9.2/10about £9.99
View offer
Stone Reef Stone Reef INOX discs (25)

Rank 3

Stone Reef Stone Reef INOX discs (25)
7.5/10about £12.99
View offer
On this page
  1. 1.Diameter and the guard
  2. 2.Depth, not a free power upgrade
  3. 3.Listing mistakes to catch before checkout
  4. 4.Which search to use

Diameter and the guard

The guard is sized for one wheel diameter. A 125 mm disc is 10 mm larger in diameter than a 115 mm disc, about 5 mm more radius. On a 115 mm guard that edge can stand proud or stop the guard closing. Reviews describe packs that will not fit a 4.5 inch grinder unless the guard comes off. Taking it off is not a fix. The 22.23 mm bore is shared on many 115 mm and 125 mm grinders in Britain, which is why listings shout the hole. Bore means the disc slides on. The guard is what contains fragments. FEPA and HSE guidance assume guarding that matches the wheel. Stone Reef’s bullets mention both sizes. HAUTMEC (B0DNZ184K8) titles 125 mm and one bullet names 115 mm. Read the guard plate before you mount. Thickness and rpm after that are the 125 mm metal cutting disc buying guide.

Depth, not a free power upgrade

A 125 mm grinder gives more depth than a 115 mm tool. Fitting a 125 mm disc does not add power to the same motor. On tube and angle, the extra 5 mm of radius can save a turn of the work on a repetitive job. Many 125 mm wheels here print about 12,200–12,250 rpm. Compare that with the grinder. A 50-pack of 125 mm Merryland discs is waste on a 115 mm machine. A 115 mm disc on a 125 mm guard leaves depth unused.
HAUTMEC HAUTMEC HT0431 discs (10)

Testsieger

HAUTMEC HAUTMEC HT0431 discs (10)
7.2/10about £10.99
View offer

Listing mistakes to catch before checkout

Titles repeat 125 mm and 22.23 mm. Bullets are sometimes copied from another size. HAUTMEC’s 115 mm bullet on a 125 mm title is the pattern. A UK buyer in that file ordered 125 mm for a 115 mm grinder and left the tin sealed. A DeWalt review title says 115 × 1.2 mm on the 125 mm ASIN. That is review noise, not the specification. Eclipse (B0DZXSCMCD) prints 222.23 mm in the title. Check the ring. That is not a third diameter. WojBear lists a 22 mm bore, a reducer, and a 115 mm claim. The Merryland Craft-Line 25-pack and 50-pack show 8,007 and 8,013 reviews with the same UK text, which is not a guard-fit test of your grinder. Read for “would not fit a 4.5 inch”. Mounting, once the size matches, is how to use a 125 mm cutting disc.

Common questions

Will a 125 mm disc fit my 115 mm grinder if the bore is 22.23 mm?
The bore may fit the spindle. The guard is not rated for the larger wheel. Do not mount a 125 mm disc on a 115 mm guard, and do not remove the guard to force it. Buy 115 mm discs for a 115 mm guard.
Is 125 mm the same as 5 inch?
Retailers use both labels for this mid-size small grinder. A 115 mm tool is often sold as 4.5 inch. Confirm the engraving on your guard rather than assuming an inch rounding matches every import brand.
Can I remove the guard to make a larger disc fit?
No. Removing the guard takes away the containment HSE abrasive-wheel guidance expects. A UK review of Stone Reef says the disc does not fit a 4.5 inch grinder unless the guard comes off. The fix is a smaller disc, or a grinder whose guard matches the wheel.
Why do listings say the disc fits both sizes?
Bullets sometimes aim at more than one size. HAUTMEC titles 125 mm and one bullet says 115 mm grinders. Stone Reef’s bullets say 115 mm and 125 mm. WojBear’s bullets also claim 115 mm grinders. Verify with the tool, not with a copied line.
I have a 125 mm grinder. Should I ever buy 115 mm discs?
Only if the manufacturer explicitly allows a smaller wheel with that guard, in the manual. The default is to match the guard rating printed on the tool. A 115 mm disc on a 125 mm guard leaves cutting depth unused.
Does a 125 mm disc run slower than a 115 mm disc?
The maximum rpm is set by the manufacturer for that wheel. Read it on the ring. Many 125 mm wheels in this set print near 12,200–12,250 rpm. Your grinder’s no-load speed must not exceed that mark, whatever diameter class you searched.
Which comparison rows show the size mix-up?
HAUTMEC mixes a 115 mm bullet with a 125 mm title. Stone Reef mentions 115 mm and 125 mm grinders on a 125 mm disc. A DeWalt review title says 115 × 1.2 mm on the 125 mm tin. Treat each as a prompt to check the guard, not as a second specification.

Related pages

Best 125 mm metal cutting disc

125mm metal cutting disc

125mm metal cutting disc buying guide: order of checks

How to use a 125mm cutting disc on an angle grinder

125mm stainless steel cutting disc: reading INOX labels

Sources

Sources taken from the research digest. Prices, stars and review counts are the stored amazon.co.uk listing figures from 19 October 2026.

  1. HSE HSG17 — Safety in the use of abrasive wheels (retrieved 19.10.2026)
  2. HSE — PUWER overview (retrieved 19.10.2026)
  3. FEPA — bonded abrasives safety leaflet (retrieved 19.10.2026)
  4. Abrasives Safety — reinforced bonded wheels on angle grinders (retrieved 19.10.2026)
  5. THSP G712 — cutting-off discs (retrieved 19.10.2026)
  6. Würth UK catalogue — 125 mm cutting discs (retrieved 19.10.2026)
  7. Axis Tools — 125 mm OSA cutting disc (retrieved 19.10.2026)
  8. amazon.co.uk product listings (retrieved 19.10.2026)