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100 mm versus 115 mm wood carving disc

Updated: 21 October 2026

You have either a compact 4 inch grinder or a 115 mm one, and a 100 mm versus 115 mm wood carving disc is not a small upgrade you can ignore. The disc's outer diameter has to match the guard. The bore can look identical on both sizes and still not make them interchangeable. Our [rasp disc comparison](/hub/sanders/rasp-disc) keeps both classes, plus one 125 mm set, with amazon.co.uk prices on 20 October 2026 from £6.89 to £28.49. The Products Compared editorial team compared listings, not a measured guard in a workshop. A qualifying purchase through our links can earn a commission at no extra cost to you.

You have either a compact 4 inch grinder or a 115 mm one, and a 100 mm versus 115 mm wood carving disc is not a small upgrade you can ignore. The disc's outer diameter has to match the guard.

Our top picks

OBA OBA OGD17

Best overall

OBA OBA OGD17
9.4/10about £13.99
View offer
Techfection Techfection 125 mm set

Best value

Techfection Techfection 125 mm set
8.1/10about £13.59
View offer
EJUXPSE EJUXPSE SL003

Rank 3

EJUXPSE EJUXPSE SL003
6.2/10about £10.99
View offer
On this page
  1. 1.Read the nameplate and the guard first
  2. 2.When a 100 mm disc is the one you need
  3. 3.The 115 mm size most trade grinders use
  4. 4.The 125 mm listing in the same table
  5. 5.The bore still has to fit

Read the nameplate and the guard first

The grinder decides the disc, not the other way round. Look at the guard and the rating plate for 100 mm, 115 mm or 125 mm. A 115 mm disc on a 100 mm guard stands proud of the guard. Standing proud is the failure to avoid. Do not remove the guard to gain clearance. A smaller disc on a larger guard is a different mismatch: use the disc size that guard was built around. 4 inch and 100 mm are the same class for this purpose. 4.5 inch is the inch name many sellers use for 115 mm. 5 inch is the usual inch name for 125 mm. If your plate is worn, take the size from the manual, not from the hole in the middle of a disc. Chainsaw-style blades are a different mistake, covered on rasp disc versus chainsaw disc.

When a 100 mm disc is the one you need

A 100 mm carving disc belongs on a 4 inch grinder: the small corded machines and many cordless bodies sold with a 100 mm guard. The disc is the one that stays inside that guard. You cannot gain a 115 mm wheel by deciding the job is only a door. In this set the EJUXPSE title states 4 inch (100 mm) and tungsten carbide, at £10.99, with 4.0 from 13 reviews. One title says not fit for purpose. The specification's item count is 1 against a three-piece title, and speed and bore are blank. It is not a confirmed fit until the disc clamps flat. YUXNVI's title also says 4 inch, while the diameter field says 46 millimetres and the material field says aluminium oxide. The EN 12413 line on that page is not a size certificate.
OBA OBA OGD17

Testsieger

OBA OBA OGD17
9.4/10about £13.99
View offer

The 115 mm size most trade grinders use

A 115 mm guard is the common trade size. The disc to match is 115 mm, not "about 4.5 inch, so 100 mm is close enough" and not a 125 mm wheel you happen to have in the box. The OBA OGD17 is a single carbon-steel disc at £13.99, with a stated 22.23 mm arbor, 12,000 rpm, and 4.5 from 1,558 reviews. It is the top pick when you want one 115 mm wheel with that review depth, and it is still the wrong disc on a 100 mm guard. Which kept pack suits a door or a bowl is on best wood carving discs. Pomsare W115C is four 115 mm discs at £28.49, stated 12,200 rpm. The title says tungsten carbide and the table says carbon steel.

The 125 mm listing in the same table

One kept set is neither 100 nor 115. Techfection lists three discs at 125 millimetres, £13.59, 1.03 kg, 4.5 from 245 reviews, with 22 mm in the title and no maximum speed in the specification. That is the best value line only if your guard is 125 mm. On a 115 mm grinder it is the oversized disc, the same class of mistake as a 115 mm disc on a 100 mm guard. Do not swap the guard unless the replacement is the correct part for that grinder.

The bore still has to fit

Matching 100 mm to a 100 mm guard does not clamp the disc. 22.23 mm is 7/8 inch, common on 115 mm and 125 mm machines. A 100 mm grinder is sometimes the same bore and sometimes not. EJUXPSE does not print a bore. The OBA includes an inner diameter ring. 5/8 inch, as claimed on DVDVBOOM, is not 22.23 mm. A 100 mm grinder often has a higher no-load speed than a 125 mm grinder. The disc mark must still be at least that no-load figure. The wider buying order, including material and rpm, is in the wood carving disc buying guide.

Common questions

Can I put a 115 mm carving disc on a 100 mm grinder?
No. The OBA and the Pomsare are 115 mm discs. On a 100 mm guard they stand proud. Removing the guard is not a workaround. Use a disc whose stated diameter is 100 mm or 4 inch, then confirm the bore. The EJUXPSE is the kept title that states that size, with a thin review sample and no printed rpm. ChongYue's 4 inch claim sits next to a blank diameter.
Is 4.5 inch the same as 115 mm?
For guard matching, sellers often use 4.5 inch to mean 115 mm. It is not the same as 4 inch or 100 mm, and it is not the same as 125 mm or 5 inch. DVDVBOOM's title offers 4 inch or 4.5 inch, and the specification field says 4 inches only. If your guard is marked 115, choose a listing whose diameter field says 115 millimetres.
Will the same 22.23 mm hole fit both?
Often the hole matches and the guard does not. 22.23 mm is a bore, not a disc diameter. The OBA states 22.23 mm on a 115 mm disc and includes a ring.
Which 115 mm disc has more reviews?
The OBA, at 4.5 from 1,558 reviews, against Pomsare at 4.4 from 177. The OBA is one profile at £13.99 with 12,000 rpm stated. Pomsare is four profiles at £28.49 with 12,200 rpm stated and a material clash between title and table. More reviews do not change the rule that neither disc belongs on a 100 mm guard.
What if my grinder is 125 mm?
Buy the 125 mm set, which in this comparison is the Techfection three-pack at £13.59, and accept the blank speed field. That is the best value line for a 125 mm guard, not for every grinder. Do not fit the OBA 115 mm disc by taking a 125 mm guard off, and do not fit the Techfection wheels on a 115 mm guard.

Related pages

How to use a wood carving disc

Rasp disc

Best wood carving disc: OBA top pick, Techfection set

Wood carving disc buying guide: diameter, bore, rpm

Chainsaw disc vs rasp disc: UK angle grinder safety

Sources

Sources taken from the research digest. Prices, stars and review counts are the amazon.co.uk listing figures as of 20 October 2026.

  1. GOV.UK PSA2 — angle grinder chainsaw disc (retrieved 20.10.2026)
  2. GOV.UK PSA5 — toothed saw blade attachments (retrieved 20.10.2026)
  3. HSE — PUWER overview (retrieved 20.10.2026)
  4. HSE — HSG17 abrasive wheels (retrieved 20.10.2026)
  5. Rutlands — carving discs set of 2 (retrieved 20.10.2026)
  6. Rutlands — carving discs and rasps set of 6 (retrieved 20.10.2026)