# Resin-bonded grinding wheels

Resinoid wheel construction, grain and bond markings, exact product examples, dimensional and speed labels, and evidence limits.

Reviewed: 2026-10-29

Tags: abrasives, grinding, bonded-abrasives

## Identity and related forms

Klingspor **A 24 R SUPRA 13413** is **180 × 7 × 22.23 mm** (diameter × width × bore), with **80 m/s** and **8,500 rpm** maxima. Item 13402 shares the product name but is **125 × 6 × 22.23 mm** and lists **12,250 rpm**. [Klingspor A 24 R sheet](https://www.klingspor.de/en/products/kronenflex-grinding-discs/a-24-r-supra/pdf) In a resinoid wheel, cured resin binds the grain and fillers through the wheel body. [Norton construction comparison, February 24, 2022](https://www.nortonabrasives.com/en-us/resources/expertise/right-angle-grinding-abrasives-know-your-options)

In United Abrasives’ A 24 R BF example, A is alumina, 24 is grit, R is wheel grade and BF is reinforced resinoid bond. In the bond position, R means rubber and V means vitrified. [United Abrasives marking chart](https://www.unitedabrasives.com/resources/general-safety-information/ansi-standard-marking-system-wheel-configurations/)

Grinding and cutting-off are separate intended uses. FEPA's angle-grinder leaflet illustrates Type 27 grinding wheels and Type 41 and 42 cutting-off wheels. Reinforcement does not make a cutting-off wheel suitable for side grinding. A grinding wheel's suitability for cutting also requires an explicit product statement. [FEPA leaflet, both pages, June 2016](https://fepa-abrasives.org/wp-content/uploads/2020/04/fepa-safety-leaflet-bonded-abrasives-english-baf.pdf)

## Grain, resin, reinforcement, and fillers

Klingspor's Kronenflex construction reference describes liquid and dry resins, fillers, a metal ring, and glass-fiber reinforcement. It states that its grinding discs contain at least three glass-fiber layers. This is a supplier construction statement, not a layer-count requirement for every resin-bonded wheel. Neither the statement nor the sampled product sheets identifies the resin chemistry, filler recipe, or reinforcement mass of an individual wheel. [Klingspor construction reference](https://www.klingspor.de/en/products/anwendung/kronenflex-trennscheiben)

Weiler's family SDS WSDS-046, revision B, February 18, 2022, lists these concentration intervals in section 3. [Weiler SDS, sections 1 and 3](https://mexico.weilerabrasives.com/hubfs/NA%20SDS%20Sheets/WSDS-046%20Industrial%20Resinoid%20Bonded%20Grinding%20Wheels%20SDS%20%28EN%29%20Rev.%20B%20V2.pdf)

| Listed constituent | "Conc. %" interval |
| --- | --- |
| Aluminum oxide; silicon carbide | 0–95 each |
| Zirconium oxide | 0–50 |
| Cured resin; inorganic fluoride | 0–30 each |
| Iron pyrite | 0–20 |
| Calcium compounds; sulfur compounds; woven fiberglass | 0–15 each |
| Iron oxide; titanium dioxide | 0–5 each |

"Conc. %" has no stated mass or volume basis. These product-family ranges establish neither grain purity nor any item's recipe. "Cured resin" leaves chemistry unspecified. Zero lower bounds do not prove an ingredient is absent. Section 15 attributes iron oxide, titanium dioxide, and silica to possible trace occurrence rather than deliberate addition. Its respirable-silica exposure claim supplies no test protocol. [Weiler SDS, section 3 table and section 15 note](https://mexico.weilerabrasives.com/hubfs/NA%20SDS%20Sheets/WSDS-046%20Industrial%20Resinoid%20Bonded%20Grinding%20Wheels%20SDS%20%28EN%29%20Rev.%20B%20V2.pdf)

## Grade, structure, and product names

Wheel grade describes wheel hardness, separately from the abrasive material. Norton cautions that the same grade letter need not mean equal hardness or behavior across manufacturers. Structure describes relative grain spacing or porosity. Its numerical scale is distinct from grit size, and some specifications omit it. Norton's omitted-structure convention is not evidence of an unreported structure in another supplier's wheel. [Norton marking explanation, March 26, 2021](https://www.nortonabrasives.com/en-us/grinding-wheel-basics)

Grit grades describe particle-size distributions rather than one particle diameter or achieved surface roughness. Bonded FEPA F grades and coated FEPA P grades have different distribution requirements. UAMA explains the distinction with historical standard editions. That explanation does not establish the grading standard of an unqualified product number such as "24." [UAMA particle characterization and size standards](https://uama.org/abrasives-101/)

The Klingspor sheets contain product names and pictured specification marks that differ:

| Sheet and pictured item | Product name | Specification printed in the illustration |
| --- | --- | --- |
| A 24 R sheet, item 13413 | A 24 R SUPRA | `27-A30M-BF`. [Sheet, page 1 artwork](https://www.klingspor.de/en/products/kronenflex-grinding-discs/a-24-r-supra/pdf) |
| A 24 N sheet, item 13412 | A 24 N SUPRA | `27-A30K-BF`. [Sheet artwork](https://www.klingspor.de/en/products/kronenflex-grinding-discs/a-24-n-supra/pdf) |

The pictured specifications have grit 30 and grades M and K, respectively, under the marking convention above. Neither includes a separate structure number. The sheets do not explain the differences from their product names. Artwork is not verification of a delivered item's label. [United Abrasives marking chart](https://www.unitedabrasives.com/resources/general-safety-information/ansi-standard-marking-system-wheel-configurations/), [Norton specification positions](https://www.nortonabrasives.com/en-us/grinding-wheel-basics)

## Exact dimensions and speed labels

These examples come from English-language sheets on Klingspor's German site. Both identify aluminum-oxide grain and fiber-reinforced synthetic resin. Their form drawings show a depressed center. The values below retain each sheet's maximum labels, not an optimum-speed interpretation.

| Product and exact item | Diameter × width × bore, mm | Vmax, m/s | Max. RPM | Source |
| --- | --- | --- | --- | --- |
| A 24 R SUPRA, 13402 | 125 × 6 × 22.23 | 80 | 12,250 | [A 24 R sheet, page 1](https://www.klingspor.de/en/products/kronenflex-grinding-discs/a-24-r-supra/pdf) |
| A 24 R SUPRA, 13413 | 180 × 7 × 22.23 | 80 | 8,500 | [A 24 R sheet, page 2](https://www.klingspor.de/en/products/kronenflex-grinding-discs/a-24-r-supra/pdf) |
| A 24 N SUPRA, 13412 | 180 × 6 × 22.23 | 80 | 8,500 | [A 24 N sheet](https://www.klingspor.de/en/products/kronenflex-grinding-discs/a-24-n-supra/pdf) |

The A 24 R artwork identifies item 13413, not the 125 mm item. Both sheets use graphical bond, aggression, and service-life scales without a test method or physical units. Those scales establish no transferable life or removal-rate ratio. [A 24 R sheet](https://www.klingspor.de/en/products/kronenflex-grinding-discs/a-24-r-supra/pdf), [A 24 N sheet](https://www.klingspor.de/en/products/kronenflex-grinding-discs/a-24-n-supra/pdf)

**Derived relationship.** Circular geometry gives `v = πDn / 60,000`, with diameter `D` in mm, speed `n` in rpm, and peripheral speed `v` in m/s. At the listed 180 mm and 8,500 rpm, the result is about 80.1 m/s. The sheet does not explain its rounding conventions. Arithmetic cannot resolve that difference, increase a marked limit, or establish a process setting.

Diameter, width, and bore are separate dimensions. Reinforcement is a construction property. Machine fit also depends on the mounting assembly and guards. FEPA separately illustrates flange alignment, guards, damage, expiry and traceability marking, and machine-versus-wheel speed limits. A matching bore alone does not qualify an assembly. [FEPA leaflet, marking panel and illustrated guidance](https://fepa-abrasives.org/wp-content/uploads/2020/04/fepa-safety-leaflet-bonded-abrasives-english-baf.pdf)

## Applications and standards boundaries

Klingspor lists surface grinding, edge beveling, and deburring for A 24 R SUPRA and describes steel, stainless steel, and castings. Its EN 12413 and oSa statements are manufacturer claims. They do not establish complete-assembly conformity, a customer's capability, or a particular finish. [Klingspor A 24 R product page](https://www.klingspor.de/en/products/kronenflex-grinding-discs/a-24-r-supra)

ISO 525:2020, edition 5, covers bonded-abrasive shape types, dimensional symbols, specifications, designations, and marking. Its public abstract excludes coated and superabrasive products and distinguishes dimensional and tolerance standards. ISO reports confirmation in 2026. [ISO public scope and edition record](https://www.iso.org/standard/78476.html)

DIN Media lists DIN EN 12413:2019-12, adopting EN 12413:2019, as current. Its public introduction covers safety requirements for rotating bonded abrasives, associated tests, and manufacturer information. It excludes diamond, boron-nitride, and coated abrasive tools. Only public scope and edition information is used here. [DIN Media public record](https://www.dinmedia.de/de/norm/din-en-12413/306163035)

**Synthesis.** A resin bond, reinforced construction, or listed substrate does not establish wet-use suitability, permitted side loading, contact angle, pressure, removal rate, service life, or surface finish. Nor does it prove residue-free processing or compatibility with later welding, coating, or corrosion-sensitive service. These sources contain no matched contamination or downstream-compatibility tests.

Weiler distinguishes the article from grinding dust, including workpiece dust. Extreme heat or excessive speed may cause harmful emissions. Hazard classification does not establish performance. [Weiler SDS, sections 2, 7, 8, and 11](https://mexico.weilerabrasives.com/hubfs/NA%20SDS%20Sheets/WSDS-046%20Industrial%20Resinoid%20Bonded%20Grinding%20Wheels%20SDS%20%28EN%29%20Rev.%20B%20V2.pdf)

## Source coverage and limits

Reviewed October 29, 2026 PDT. Coverage includes both pages of the A 24 R sheet, the complete one-page A 24 N sheet, their artwork and stock tables, all eleven Weiler SDS pages, both FEPA leaflet pages, and the cited public references. The Klingspor sheets are undated snapshots. The 2016 FEPA leaflet predates EN 12413:2019 and is not an edition-current normative text.

The product-name and artwork differences remain unresolved. Complete formulations, percentage bases, delivered-item labels, mounting qualification, lot tests, and matched performance trials are unavailable. Precision resin-bonded diamond and CBN wheels require their own product and standards coverage. No operating recipe or customer capability follows from these examples.

Related references cover [fiber sanding discs](fiber-sanding-discs.md), [flap discs](flap-discs.md), and [Finishing process references](../../processes/finishing/index.md).