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ASME B5.35-1983 (2018) — Machine Mounting Specifications for Abrasive Discs and Plate Mounted Wheels
🛠️ ASME B5.35-1983 (2018) is the American National Standard for the mounting of abrasive discs and plate mounted wheels. The standard was first approved as an American Standard on September 17, 1957, revised and redesignated a USA Standard on January 3, 1969, approved in this revision by ANSI on October 17, 1983, and reaffirmed in 1994 and again in 2018. What distinguishes this class of wheels from conventional grinding wheels is the mounting method: grinding is done on the exposed flat side of the wheel, and power is transmitted through inserted nuts, inserted washers, projecting studs anchored in one side of the wheel, or a mounting plate of steel or other rigid material cemented to one side. The steel wheels (machine face plates) on which these discs are mounted must be drilled with holes matching the location and pattern of the mounting elements.
💡 In one sentence, the standard specifies the location and size of the mounting elements (nuts, washers, studs, mounting plates) on the disc and the corresponding holes in the machine face plate, so that the “disc-to-machine” interface is standardized and interchangeable.
1. Standard Framework 📌
Section 1 (Purpose) states the goal: to provide standards used in the design of machine face plates matching the location of nuts, washers, or studs of abrasive discs, and the plain or tapped holes of plate mounted wheels. Section 2 (Scope): ANSI standard practice for the location and size of bolt holes for mounting abrasive discs and plate mounted wheels. Section 3 (General) classifies products into six mounting types and requires that the mounting elements be laid out in a pattern matching the corresponding holes in the machine face plate:
| Mounting Type | Carrying Structure | Power Path | Standard Clause |
|---|---|---|---|
| Inserted nut | Threaded nuts anchored in the mounting side | Bolt through face plate into anchored nut | 3.3, Figs. 1.1/1.2 |
| Inserted washer | Washers anchored in the mounting side | Bolt/screw clamps the washer | 3.4, Fig. 2 |
| Tapped mounting plate | Mounting plate cemented to the disc | Bolt from behind into tapped plate holes | 3.5, Fig. 3 |
| Projecting stud | Studs embedded in the mounting side | Face-plate holes slip over studs, nuts tighten | 3.6, Fig. 4 |
| Cylinder type | Similar to Type 2 wheels; nut/stud/plate mounting | One of the three above | 3.7, Fig. 5 |
| Plate mounted wheel | Steel or rigid plate cemented to one side | Plate holes match face-plate holes, bolted | 3.8, Fig. 6 |
Two core specification sections follow: Section 4, standard hole spacing for steel wheels (machine face plates) for abrasive discs of 10 in. through 30 in. diameter, and Section 5, standard hole spacing for steel wheels for plate mounted wheels. Figures 7–17 show the hole layouts for discs of 10/12/14/15/16, 18/20/22/23/24, 26/30, 36, 40, 42, 48, 53, 72, and 84 in. diameter, plus 10/11/14/18/20 in. cylinder-type discs.
⚠️ Only discs within the diameters tabulated in the standard are guaranteed this hole layout. Non-standard diameters or modified hole patterns must be agreed between user and manufacturer; never drill “approximately matching” patterns, which can cause eccentricity, vibration, and disc ejection.
2. Steel Wheel (Face Plate) Requirements and Hole Patterns 🔧
The machine face plate is the critical interface part: its drilled hole pattern must correspond exactly to the disc’s mounting-element pattern. The standard specifies the hole count, hole diameter, bolt-circle diameter, and bolt size for each disc diameter, and the minimum thickness of steel disc wheels (Table 1). Representative examples:
| Disc Diameter (in.) | Hole Count | Bolt Circle (typical, in.) | Bolt Size (example) | Steel Wheel Min. Thickness |
|---|---|---|---|---|
| 10–16 | 3 or 4 | Per spec | Per spec | Per Table 1 |
| 18–24 | 4 or 6 | Per spec | 1/2 in. class | Per Table 1 |
| 26–30 | 6 | Per spec | 1/2–5/8 in. class | Per Table 1 |
| 36–48 | 6–8 | Per spec | 5/8 in. class | Per Table 1 |
| 53–84 | 8+ | Per spec | 3/4 in. class | Per Table 1 |
For the inserted-nut mounting (Fig. 1.2): a clearance hole and counterbore in the face plate receive a 3/8 in.-16 × L in. socket head cap screw that passes through the plate into the anchored nut; the counterbore is machined as shown and the drill size is noted in the figure. Tapped-plate mountings use tapped holes in the plate, requiring no nut.
🚨 The accuracy of the holes and threaded elements directly determines the disc’s radial position. Asymmetric spacing or oversized holes make the disc eccentric; at high speed this causes severe vibration and raises the risk of wheel burst. Drill the face plate in one setup to the standard layout and check every hole.
3. Errata Notice 📝
In October 1985, ASME issued an Errata to ANSI/ASME B5.35-1983, Machine Mounting Specifications for Abrasive Discs and Plate Mounted Wheels. The correction:
- Location: Page 2, Fig. 1.2 — Detail of Mounting Hole and Screw for Inserted Nut Type Mounting.
- Error: the figure showed the 3/8 in.-16 × L in. socket head cap screw and its counterbore with a pointed (conical) bottom.
- Correction: the screw and counterbore must be shown with a flat bottom, so the counterbore’s bottom face is flat and seats the head of the bolt properly, as illustrated; the note adds “minimum thickness per Table 1” for the steel disc wheel, and the drill size (W drill, about 0.316 in.) is given in the figure.
✅ Engineering significance: a pointed counterbore leaves the bolt head unsupported and reduces the seating area, risking head damage or loosening under preload; with the corrected flat bottom, the head seats evenly, joint stiffness improves, and the mounting is more reliable. Holders of earlier printings should apply the corrected figure.
4. Engineering Practice Essentials 🛠️
- 🔍 Mounting selection: standard mass-produced discs favor inserted-nut mountings (quick change); applications needing a flat back prefer tapped mounting plates; heavy large-diameter wheels favor projecting studs for a larger drive diameter.
- 🔧 Hole verification: after drilling a new face plate, verify hole count and bolt-circle diameter against the standard layout so discs of different patterns are never mixed.
- 📊 Balancing and test run: balance the assembled disc (static or dynamic) and run it unloaded per B7.1 before grinding; only proceed once speed is stable and vibration is minimal.
- 📋 Wear management: replace discs when worn to the minimum thickness; read the specification number on the disc side (diameter/mounting type) so replenishment matches the existing hole pattern.
5. Frequently Asked Questions ❓
❓ Q: How do abrasive discs differ from ordinary grinding wheels?
A: Ordinary wheels grind on the periphery or face and are usually mounted on an arbor; abrasive discs are flat bonded abrasives ground on the exposed flat side, with power transmitted through embedded nuts/washers/studs or a mounting plate, so they must match the face-plate hole pattern.
A: Ordinary wheels grind on the periphery or face and are usually mounted on an arbor; abrasive discs are flat bonded abrasives ground on the exposed flat side, with power transmitted through embedded nuts/washers/studs or a mounting plate, so they must match the face-plate hole pattern.
❓ Q: Why specify the face-plate holes separately?
A: Because the disc’s mounting elements are the “male” feature and the face-plate holes the “female” feature — only when both sides are made to the same pattern can a disc mount interchangeably on any equivalent machine. That is precisely what a “machine mounting specification” provides.
A: Because the disc’s mounting elements are the “male” feature and the face-plate holes the “female” feature — only when both sides are made to the same pattern can a disc mount interchangeably on any equivalent machine. That is precisely what a “machine mounting specification” provides.
❓ Q: The errata changed only one figure — does it matter?
A: Fig. 1.2 is the detail drawing for the most common inserted-nut mounting. Changing the counterbore from pointed to flat bottom directly affects machining and loading, so it is a substantive manufacturing correction that must reach the shop drawings.
A: Fig. 1.2 is the detail drawing for the most common inserted-nut mounting. Changing the counterbore from pointed to flat bottom directly affects machining and loading, so it is a substantive manufacturing correction that must reach the shop drawings.
🔍 Q: What is the current status of this standard?
A: It is marked “REAFFIRMED 2018,” so the technical content remains in force after reaffirmation by ASME in 2018, and the 1985 errata continues to apply. Design, manufacture, and acceptance should follow both the main text and the errata.
A: It is marked “REAFFIRMED 2018,” so the technical content remains in force after reaffirmation by ASME in 2018, and the 1985 errata continues to apply. Design, manufacture, and acceptance should follow both the main text and the errata.
