The best 125 mm flap discs, compared.
Top pick: Gmozkrn 125 mm flap disc Best value: Merryland 40 grit 20-pack – Best price per disc among single-grit packs with a printed speed and more than 200 reviews. Twenty 40 grit discs at £21.90, about £1.10 each, 4.6 from 221 reviews, 12,250 rpm. Updated October 2026.
A 125 mm flap disc is a coated abrasive wheel for a 125 mm angle grinder. Overlapping flaps sit on a fibreglass or plastic hub with a 22.23 mm bore, not a 22.0 mm hole. You use it to clean welds, deburr, lift rust and blend steel, and sometimes wood, where a rigid grinding disc is too aggressive or too flat on a contour. Quality shows up in the grain, the profile and a printed maximum speed. Type 29 is the conical face for edges and welds. A title that says stainless is not an iron-free claim unless the listing says so. Match the disc marking to the grinder and keep the guard on. Bore, rpm, profile and grit are set out on the [125 mm flap disc buying guide](/hub/sanders/flap-discs-125/sub/flap-discs-125-buying-guide). The usual bore is 22.23 mm, which is 7/8 inch, not a 22.0 mm hole. A rigid grinding disc is the wrong shape when the surface is contoured or when you only need to blend. The seven packs are amazon.co.uk listings from .
A 125 mm flap disc is a coated abrasive wheel for a 125 mm angle grinder. Overlapping flaps sit on a fibreglass or plastic hub with a 22.23 mm bore, not a 22.0 mm hole.
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Personal buying guide
Question 1 of 2
What is the job?
The Gmozkrn listing is a nine-disc 125 mm Type 29 pack at £12.99, rated 5.0 from only four amazon.co.uk reviews, in a 60/80/120 mix with aluminium oxide grain. One reviewer called it a handy set for a refurbish and repair, and another review title says the grits are not marked on the discs. Four ratings cannot carry a 5.0 the way a few hundred reviews can, so the star line is a thin sample. Maximum speed is absent from the technical fields, and the stored pack line is empty. The materials list names metal and wood, not stainless steel. The sales rank sits under hook-and-loop discs, which is an odd shelf for a flap disc. You are looking at a cheap mixed box for light DIY, and you do not yet have a speed figure or a review base to lean on.
Pros
Cons
Best for: You want a small mixed pack for light metal and wood tidying and you accept a four-review sample.
Less suitable: You want a printed speed, a single grit, or a review count in the hundreds.
Specifications
Common questions
What size is this disc?
The title and the diameter field describe 125 mm. The title is a nine-disc Type 29 pack in 60, 80 and 120 grit. The stored bore is 22.23 mm typical.
Is stainless steel named?
The materials line lists metal and wood. Stainless steel is not named.
Which profile and speed are listed?
The identifier field reads Type 29. Maximum speed is not in the technical fields. A review title says the grits are not marked on the discs, and there are only four amazon.co.uk reviews.
The MIDO Professional Abrasive pack is twenty 125 mm Type 29 flap discs at £24.99, rated 4.8 from 16 amazon.co.uk reviews, in a 40/60/80/120 mix of zirconia alumina with a maximum speed of 12,200 rpm. Reviewers say the discs last, and one buyer was using the 40 grit to lift old floor adhesive. Sixteen ratings is a short file next to the Merryland packs, which sit above 200 reviews at a lower shelf price. The Amazon grit field prints 120 even though the title is a four-grit mix. Materials are metal and wood, so stainless is not named. You pay the highest price in this set for a printed 12,200 rpm line, and the review count is too small to treat 4.8 as a settled result.
Pros
Cons
Best for: You want a mixed zirconia box that states 12,200 rpm, and you can live with a 16-review sample.
Less suitable: You want a large review file, a lower shelf price, or a listing that names stainless steel.
Specifications
Common questions
What size is this disc?
The title and the diameter field describe 125 mm. The pack line is twenty Type 29 discs in 40, 60, 80 and 120 grit. The stored bore is 22.23 mm typical.
Is stainless steel named?
The materials line lists metal and wood. Stainless steel is not named, and the listing does not say the grain is iron-free.
Which profile and speed are listed?
The identifier field reads Type 29, and the maximum speed is 12,200 rpm. The Amazon grit field shows 120 even though the title is a four-grit mix.
The Merryland 80 grit pack is ten 125 mm flap discs at £12.90, rated 4.7 from 259 amazon.co.uk reviews, with a maximum speed of 12,250 rpm in the technical fields. Reviewers used them to strip rust from a 30-year-old car rear beam and to take paint off metal, and several call the price fair. One UK review says they wear slightly quicker than some other discs that buyer had used. The title says T29 and 80 grit zirconia alumina, while the profile field prints ANSI B7.1-2010, so the shape is clearer in the title than in that identifier. Stainless steel is in the materials list, and the listing does not claim an iron-free grain. You pay the same £12.90 as the 40 grit ten-pack, and you are buying a finer blending grit rather than a heavy stock-removal disc.
Pros
Cons
Best for: You want an 80 grit zirconia disc for blending and light rust on mild steel, at the same shelf price as the 40 grit ten-pack.
Less suitable: You need 40 grit for heavy weld grinding, or a disc the listing marks as iron-free.
Specifications
Common questions
What size is this disc?
The title and the diameter field describe 125 mm. The pack line is ten 80 grit pieces. The stored bore is 22.23 mm typical.
Is stainless steel named?
The materials line lists metal, iron, stainless steel, steel, sheet metal and steel pipe. The listing does not say the grain is iron-free.
Which profile and speed are listed?
The title says T29 and the maximum speed is 12,250 rpm. The profile field prints ANSI B7.1-2010, so the shape is clearer in the title than in that identifier.
The Merryland 10-pack of 40 grit discs is ten 125 mm Type 29 flap wheels at £12.90, rated 4.6 from 330 amazon.co.uk reviews, the largest sample in this set, with a maximum speed of 12,250 rpm. Reviewers say they last, get metal grinding done, and run quieter than a rigid grinding disc. The title and the pack line agree on 40 grit and ten pieces, so you are not decoding a mixed box. One review is titled as cheap quality while the visible text still calls the discs very good, and the stored file records no repeated defect theme. Zirconium grain and a Type 29 face suit weld and stock removal, and the materials line includes stainless steel without saying the disc is iron-free. You get the deepest UK review file at the joint-lowest cash outlay in this set, and 40 grit is the wrong disc once you only need to blend a surface.
Pros
Cons
Best for: You want a first coarse zirconia pack for welds and stock removal, with a printed speed and a large UK review file.
Less suitable: You need 80 grit or finer for a visible finish, or a disc sold as iron-free.
Specifications
Common questions
What size is this disc?
The title and the diameter field describe 125 mm. The pack line is ten 40 grit Type 29 pieces. The stored bore is 22.23 mm typical.
Is stainless steel named?
The materials line lists metal, iron, stainless steel, steel, sheet metal and steel pipe. The listing does not say the grain is iron-free.
Which profile and speed are listed?
The identifier field reads 40 T29, and the maximum speed is 12,250 rpm. That is a conical Type 29 face, not a flat Type 27.
The Merryland 20-pack is twenty 125 mm 40 grit Type 29 flap discs at £21.90, rated 4.6 from 221 amazon.co.uk reviews, listed at 12,250 rpm and about 2 kg. Reviewers say they fit a Bosch angle grinder, last a long time, and work on welds. That is about £1.10 a disc against £1.29 for the ten-pack of the same grit, so the saving shows up if you will use the extra ten. The grain field says zirconium corundum, and stainless steel is named in the materials without an iron-free claim. The stored review file does not show a repeated defect theme. You spend £21.90 up front for the lower price per disc, and you are still on coarse 40 grit rather than a finishing set.
Pros
Cons
Best for: You will get through a lot of coarse 40 grit discs on mild steel and you want the lower price per disc.
Less suitable: You only need a handful of discs this month, or you need 80 grit and finer in the same box.
Specifications
Common questions
What size is this disc?
The title and the diameter field describe 125 mm. The pack line is twenty 40 grit Type 29 pieces. The stored bore is 22.23 mm typical.
Is stainless steel named?
The materials line lists metal, iron, stainless steel and steel. The listing does not say the grain is iron-free.
Which profile and speed are listed?
The identifier field reads 40 T29, and the maximum speed is 12,250 rpm. Reviewers report a fit on a Bosch angle grinder and use on welds.
The GZKTY pack is twenty 125 mm flap discs at £18.99, rated 4.6 from 119 amazon.co.uk reviews, sold as a 40/60/80/120 mix on a Type 29 zirconia hub. Reviewers call the set good value and say the discs do the jobs they bought them for. The Amazon grit field still prints 40, so the mix lives in the title and the variant line rather than in that single number. Maximum speed is missing from the technical fields, so you cannot check the disc against your grinder from the listing alone. Stainless steel appears beside metal and wood in the materials line, and the listing does not say the grain is iron-free. You get a lot of discs for under £19, and you still have to read the rpm stamped on the disc before it goes on a 125 mm grinder.
Pros
Cons
Best for: You want one mixed zirconia box for occasional rust, welds and a light finish, and you will read the rpm on the disc itself.
Less suitable: You need a printed maximum speed before you order, or a single grit you can reorder without guessing.
Specifications
Common questions
What size is this disc?
The title and the diameter field describe 125 mm. The title states a 20-pack in 40, 60, 80 and 120 grit. The stored bore is 22.23 mm typical.
Is stainless steel named?
The materials line lists metal, stainless steel and wood. The listing does not say the grain is iron-free.
Which profile and speed are listed?
The identifier field reads zirconia corundum T29. Maximum speed is not in the technical fields. The Amazon grit number shows 40 for this mixed title.
The Flintronic pack is ten 125 mm flap discs at £12.99, rated 4.3 from 43 amazon.co.uk reviews, sold as four 40 grit, two 60, two 80 and two 120, in aluminium oxide with a Type 27 profile. The technical fields list a maximum speed of 13,300 rpm, which sits above the 12,200 rpm figure Eisenblätter UK gives for a 125 mm flap disc at 80 m/s, so you still match that printed speed to the plate on your grinder. A reviewer said they take old paint off and do not last long. The title writes the bore as 22 mm, while the usual bore for this diameter is 22.23 mm. Stainless steel, cast iron, sheet metal and wood are all named, and nothing in the listing says the grain is iron-free. You get the only flat Type 27 mix in this set, and the star rating and the life comment are weaker than the Merryland rows.
Pros
Cons
Best for: You want a flat Type 27 mix for paint and light surface work, and you will check the bore and the grinder speed.
Less suitable: You need a long-lasting zirconia disc for welds, or a single grit with a few hundred reviews.
Specifications
Common questions
What size is this disc?
The title and the diameter field describe 125 mm. The title writes the bore as 22 mm. The usual bore for this diameter is 22.23 mm, which is what the stored bore field says.
Is stainless steel named?
The materials line lists stainless steel, cast iron, sheet metal and wood. The listing does not say the grain is iron-free.
Which profile and speed are listed?
The identifier field reads T27, the flat profile in this set. The maximum speed is 13,300 rpm, above the 12,200 rpm figure for a 125 mm disc at 80 m/s, so match it to the plate on your grinder.
Seven amazon.co.uk 125 mm flap disc packs were scored for this page. Weights sum to 100. Speed context is the Eisenblätter UK table, about 12,200 rpm for a 125 mm disc at 80 m/s, not a measurement taken here. Review themes come from the stored UK review notes. There was no lab test. Shelf prices run from £12.90 to £24.99.
Amazon evidence
35%Star rating on amazon.co.uk, with a heavy deduction when the count is below about 50 and a lighter deduction below 200. A 5.0 from four reviews does not outrank a 4.6 from a few hundred.
Listing fit
30%A printed maximum rpm, a grit story that matches the title, zirconia for steel stock removal, and a profile you can read as Type 29 or Type 27. A missing speed line loses this block. Stainless in a materials line does not count as an iron-free claim.
Review outcome
20%UK themes for welds, rust and paint score higher than a disc that does not last long, unmarked grits, or a sample too small to show a defect pattern.
Value
15%Shelf price in GBP against disc count, only among packs you can actually specify. A lower price per disc does not win this block when the speed is missing.
The checks run in this order: diameter and bore, maximum rpm, profile, grit and grain, then whether the pack is really one grit. The table is seven amazon.co.uk 125 mm flap disc listings. A rigid grinding wheel and a cutting disc are different comparisons. No disc was timed. A 5.0 from four reviews is not the same evidence as a 4.6 from a few hundred.
A 125 mm flap disc is a coated abrasive wheel for an angle grinder. Overlapping abrasive flaps sit on a fibreglass or plastic hub. The usual bore is 22.23 mm, which is 7/8 inch, not a 22.0 mm hole. You use these discs to clean welds, deburr, lift rust and blend on steel, stainless steel and sometimes wood. A rigid grinding disc is the wrong shape when the surface is contoured or when you only need to blend. The seven packs on this page are amazon.co.uk listings from October 2026.
A 115 mm disc or a 50 mm die-grinder disc does not belong under a 125 mm guard. This comparison kept only 125 mm listings.
A cutting disc is for the edge. A flap disc works on the face, at an angle, for welds, rust and blending. Do not swap them.
The grinder speed must not exceed the disc marking. A title that says stainless is not an iron-free claim. Do not use a mild-steel disc on stainless and assume it is clean.
Type 29 is the conical face for edges, welds and stock removal at about 15 to 25 degrees. Type 27 is flatter and suits surface work. Flintronic is the only Type 27 pack here. The Merryland 40 grit packs and the GZKTY, MIDO and Gmozkrn listings read as Type 29. The Merryland 80 grit title says T29 while the profile field prints ANSI B7.1-2010. How the two profiles meet the work is on the [Type 29 and Type 27](/hub/sanders/flap-discs-125/sub/flap-discs-125-t29-vs-t27) page. Grit follows the job.
The grinder no-load speed must not exceed the disc. For 125 mm at 80 m/s, the Eisenblätter UK table gives about 12,200 rpm, which is also the figure EN 13743 tables often allow. Merryland prints 12,250 rpm. MIDO prints 12,200 rpm. Flintronic prints 13,300 rpm, so you still match that number to the plate on the grinder. GZKTY and Gmozkrn have no maximum speed in the technical fields. A missing speed line is why a cheaper price per disc does not win the value block.
Three typical situations, each with a recommendation from this comparison.
You want one mixed zirconia box for rust, welds and a light finish. The GZKTY 20-pack is £18.99, 4.6 from 119 reviews, Type 29, titled 40/60/80/120. Maximum speed is not in the technical fields, so you read the rpm on the disc.
You want a predictable 40 grit Type 29 disc and a large review file. The Merryland 10-pack is the top pick at £12.90, 4.6 from 330 reviews, with 12,250 rpm printed. It is coarse, so blending still needs another grit.
None of these seven listings claim an iron-free grain. The Merryland 40 grit 10-pack names stainless steel beside other metals, at £12.90 with 330 reviews. If cross-contamination matters, do not treat that line as an INOX disc.
The top pick is the Merryland 10-pack of 40 grit Type 29 discs, at £12.90, with 4.6 from 330 amazon.co.uk reviews and a listed maximum speed of 12,250 rpm. It has the largest review file in this set. The best value is the Merryland 20-pack of the same 40 grit, at £21.90, with 4.6 from 221 reviews, about £1.10 a disc against £1.29 for the ten-pack. A 5.0 from four reviews does not outrank a 4.6 from a few hundred. A lower price per disc does not win when the maximum speed is missing from the listing.
Merryland 40 grit 20-pack
Best price per disc among single-grit packs with a printed speed and more than 200 reviews. Twenty 40 grit discs at £21.90, about £1.10 each, 4.6 from 221 reviews, 12,250 rpm.
Editorial
Peter F. is the editor for DIY & tools at productscompared.co.uk. Comparisons in this category are checked against amazon.co.uk listings, review evidence and public UK sources.
Guides on what to look for, how to use a product, and common mistakes.
Sources taken from the research digest. Prices, stars and review counts are the stored amazon.co.uk listing figures.
This article contains affiliate links. If you buy through these links we may earn a small commission, at no extra cost to you. Prices, stars and review counts come from stored amazon.co.uk listings. We did not run a lab test.
