# Vitrified grinding wheels

Vitrified wheel bonds, abrasive families, specification codes, exact product examples, and the limits of composition and speed evidence.

Reviewed: 2026-10-29

Tags: abrasives, grinding, reference

## Identity and construction

Norton Type 05 items **66253044790** (32A46-IVBE, grade I) and **66253044382** (32A46-JVBE, grade J) both list **8 × 1 × 1-1/4 in**. Their maximum-speed fields show **3105** and **3600**, respectively, with no unit displayed in the table. [Norton 32A item table](https://www.nortonabrasives.com/en-us/product/norton-32a-type-05-toolroom-wheel) Vitrified wheels use a glass or glass-ceramic bond. Pores accommodate chips and coolant. [Norton bond selection, July 20, 2017](https://www.nortonabrasives.com/en-us/resources/expertise/bond-selection-production-grinding)

Norton’s Premium Blue 3SG page lists ceramic alumina grain, calls the bond “high performance,” and prints 3X in the product table. That wording leaves the specific bond unresolved. [Norton Premium Blue 3SG product page and complete part table](https://www.nortonabrasives.com/en-us/product/norton-premium-blue-3sg-type-01-bench-and-pedestal-wheel)

Conventional wheels include aluminum oxide and silicon carbide. Superabrasive wheels contain diamond or cubic boron nitride, abbreviated CBN or cBN. Norton describes superabrasive segments mounted on a hub or core. A vitrified stone or stick shares a bond family without becoming a rotating wheel. ISO 525 explicitly lists wheels, segments, sticks, and stones as different bonded-abrasive forms and excludes coated and superabrasive products from its scope. [Norton wheel construction](https://www.nortonabrasives.com/en-us/grinding-wheel-basics), [ISO 525:2020 public abstract](https://www.iso.org/standard/78476.html)

## Grade, grit, structure, and bond codes

Norton's example `32A46-I8VBE` separates these specification positions. The explanation is a supplier convention, not a complete formulation. [Norton specification explanation, March 26, 2021](https://www.nortonabrasives.com/en-us/grinding-wheel-basics)

| Position | Meaning in the Norton example | Boundary |
| --- | --- | --- |
| `32A` | Abrasive identification | Supplier grain designation, not a chemical assay. |
| `46` | Abrasive grit size | Separate from wheel grade and pore spacing. |
| `I` | Wheel grade or hardness | The same letter need not give equal behavior across suppliers. |
| `8` | Structure, or relative grain spacing and porosity | Larger numbers mean a more open structure in this convention. This is not a measured pore-volume percentage. |
| `VBE` | Bond and modifiers | `V` identifies vitrified bond. Remaining characters distinguish the supplier's bond variants. |

Norton treats an omitted structure number as 8 in that explanation. The convention supplies neither a measured pore size nor a universal rule for other manufacturers. [Norton omitted-structure and bond notes](https://www.nortonabrasives.com/en-us/grinding-wheel-basics)

Norton relates bond grade to grain retention and release, separately from grain toughness and friability. That is not the intrinsic hardness of an individual grain. [Norton specification factors](https://www.nortonabrasives.com/en-us/resources/expertise/7-factors-used-determine-grinding-wheel-specification)

United Abrasives calls the grade position bond hardness. Its chart distinguishes `V` from resin `B`, reinforced resin `BF`, and rubber `R`. [United Abrasives marking chart](https://www.unitedabrasives.com/resources/general-safety-information/ansi-standard-marking-system-wheel-configurations/)

Grit grades describe distributions of particle sizes. UAMA explains that size also depends on the measurement method and particle shape. A grit number alone establishes neither one particle diameter nor an achieved surface roughness. The grading system and edition remain separate from the wheel's structure code. [UAMA particle characterization and sizing discussion](https://uama.org/abrasives-101/)

## Exact conventional-wheel examples

The following are selected rows, not a complete catalog. `D × T × H` means diameter, thickness, and arbor-hole diameter. `B` below is the web table's recess diameter, not the bond code. Dimensions are inches. Both web tables label their numeric speed field "Max Operating Speed" without displaying a unit in the retrieved header or rows. Values are retained as printed rather than converted into operating settings.

| Exact Norton item | Specification and form | D × T × H, in | Recess B diameter, in | Printed maximum-speed field | Source |
| --- | --- | --- | --- | --- | --- |
| 66252942205 | `32A60-KVBE`, Type 05 | 7 × 3/4 × 1-1/4 | 2-3/4 | 3600 | [32A table](https://www.nortonabrasives.com/en-us/product/norton-32a-type-05-toolroom-wheel) |
| 66253044790 | `32A46-IVBE`, Type 05 | 8 × 1 × 1-1/4 | 3-1/4 | 3105 | [32A table](https://www.nortonabrasives.com/en-us/product/norton-32a-type-05-toolroom-wheel) |
| 66253044382 | `32A46-JVBE`, Type 05 | 8 × 1 × 1-1/4 | 3-1/4 | 3600 | [32A table](https://www.nortonabrasives.com/en-us/product/norton-32a-type-05-toolroom-wheel) |
| 66253116265 | `39C60-IVMT`, Type 01 | 10 × 1-1/2 × 1-1/4 | Not listed | 3250 | [39C table](https://www.nortonabrasives.com/en-us/product/norton-39c-type-01-bench-and-pedestal-wheel) |
| 66253319968 | `39C60-JVMT`, Type 01 | 14 × 2 × 1-1/2 | Not listed | 2320 | [39C table](https://www.nortonabrasives.com/en-us/product/norton-39c-type-01-bench-and-pedestal-wheel) |

The 32A page describes monocrystalline aluminum oxide, vitrified bond, and a recess on one side. Its introductory text says "2A" although its title and specifications say `32A`. The 39C page identifies green silicon carbide and vitrified bond. Its introduction spells the abrasive "silicone carbide," while its features and table say silicon carbide. These textual discrepancies remain unresolved. Neither page gives a complete bond recipe or reinforcement construction. [32A description](https://www.nortonabrasives.com/en-us/product/norton-32a-type-05-toolroom-wheel), [39C description](https://www.nortonabrasives.com/en-us/product/norton-39c-type-01-bench-and-pedestal-wheel)

**Synthesis.** The two 8-inch examples have the same listed dimensions, grit, and bond suffix but different grade letters and maximum-speed fields. Diameter alone cannot determine a wheel's rating. A matching bore also leaves recess depth, tolerances, flange geometry, guards, and assembly suitability unresolved.

## Composition and fired-phase evidence

Radiac SDS06, revision printed `08/07/2024`, covers wheels or stones marked `V`. Section 3 reports these ceilings for variable compositions, with exact composition withheld. [Radiac SDS06, sections 1 and 3](https://img.tyrolit.com/files/b3dywrhp/production/365a1636590461ee147eb926f2d0e73172ce332d.pdf)

| Listed constituent | Concentration ceiling |
| --- | --- |
| Aluminum oxide | ≤95% |
| Silicon carbide | ≤95% |
| Glass or glass/porcelain | ≤40% |
| Titanium dioxide | ≤1% |
| Quartz silica | ≤1% |
| Possible sulfur, paraffin, or resin treatment | ≤35% for each listed treatment |

The table gives no mass or volume basis. Whole-product family ceilings establish neither a recipe, grain purity, nor isolated bond chemistry. Section 9 gives relative density 1.5–3.1 without a method. It cannot establish grain density, porosity, or packed-wheel bulk density. [Radiac SDS06, sections 3 and 9](https://img.tyrolit.com/files/b3dywrhp/production/365a1636590461ee147eb926f2d0e73172ce332d.pdf)

**Synthesis.** An oxide analysis or unfired recipe does not identify fired phases. The disclosures do not establish a lot-specific phase assay or silica absence. Resin treatment does not redefine the bond. No firing cycle, pore geometry, filler fraction, or reinforcement specification is supplied for the compared items.

## Superabrasives and speed terminology

Diagrind separately lists `V`, vitrified, and `VM`, vitreous metal, as bond families. Its `V` row describes diamond for carbide and CBN for steel, nominal diameters 1/8–2 inches, and a shared "Cutting Speed" of 4,000–6,000 surface feet per minute, or SFPM. It does not label that range a maximum. The CBN diameter text contains a leading decimal before the fraction. Both coolant notes concern wheels over 2 inches, outside the stated size range. Those inconsistencies do not establish a corrected range or wet-use condition. [Diagrind complete bond-selection table](https://www.diagrind.com/bond-selection-guide)

**Derived relationship.** Circular geometry gives `v = πDn / 60,000`, where `D` is diameter in mm, `n` is rpm, and `v` is peripheral speed in m/s. A hypothetical 200 mm wheel at 3,000 rpm has a peripheral speed of about 31.4 m/s. This calculation supplies no permissible, optimum, or maximum operating speed and does not interpret a unitless catalog field.

## Public standards and qualification boundaries

The following records establish public scope and edition status, not the contents of paid standards or conformity of a supplied wheel.

| Public record | Scope and edition boundary |
| --- | --- |
| [ISO 525:2020](https://www.iso.org/standard/78476.html) | Edition 5, confirmed in 2026. Bonded-abrasive shapes, designation, and marking. Excludes superabrasives and coated abrasives. Dimensions, unbalance, and tolerances have separate referenced standards. |
| [ISO 6104:2005](https://www.iso.org/standard/36553.html) | Edition 2, confirmed in 2025. Survey, designation, and nomenclature of rotating diamond or CBN tools. |
| [ISO 22917:2016](https://www.iso.org/standard/64774.html) | Edition 2, confirmed in 2022. Limit deviations and run-out tolerances for diamond or CBN precision tools with the bonded cores, circular bores for clamping flanges, or cylindrical spindles for collets identified in its abstract. |
| [DIN EN 12413:2019-12](https://www.dinmedia.de/de/norm/din-en-12413/306163035) | DIN Media lists the adoption of EN 12413:2019 as current. Safety requirements for rotating bonded abrasives, excluding diamond, boron-nitride, and coated products. |
| [DIN EN 13236:2019-07](https://www.dinmedia.de/de/norm/din-en-13236/293279098) | DIN Media lists the adoption of EN 13236:2019 as current. Safety requirements for superabrasives. A separately listed [2026 draft](https://www.dinmedia.de/de/norm-entwurf/din-en-13236/403985301) is not evidence that this published edition has been replaced. |

**Synthesis.** Vitrified bond does not transfer a conventional-wheel standard's scope to diamond or CBN. A public standard record, nominal dimensions, or a supplier application claim does not establish lot acceptance, complete-assembly conformity, or customer qualification.

The Radiac SDS distinguishes wheel ingredients from dust and fumes produced by the workpiece and coatings. Its hazard information supplies no process-performance test. [Radiac SDS06, sections 2 and 10](https://img.tyrolit.com/files/b3dywrhp/production/365a1636590461ee147eb926f2d0e73172ce332d.pdf)

## Source coverage and limits

Reviewed October 29, 2026 PDT. Coverage includes the complete retrieved Norton Basics and Bond Selection article bodies, the 32A and 39C product descriptions and part tables, the Premium Blue table, Diagrind's complete bond table, all seven Radiac SDS pages, and the cited public standards records. Product pages and Diagrind's table have no stated technical revision. The Norton explanatory articles date to 2021 and 2017. The SDS revision is retained in its printed numeric form.

Missing evidence includes delivered-item speed units and labels, full mounting drawings, formulations, phase assays, quantified porosity methods, and matched performance trials. No universal dressing method, coolant recipe, wet-use permission, contact pressure, service life, removal rate, finish, or contamination-free result follows. Publication and customer process qualification remain separate decisions.

Related references cover [resin-bonded grinding wheels](resin-bonded-grinding-wheels.md), [nonwoven abrasive pads](nonwoven-abrasive-pads.md), and [Finishing process references](../../processes/finishing/index.md).