1910.215(d): Mounting Grinding Wheels
Right before mounting, users must closely inspect and ring test grinding wheels for damage and check that the spindle speed does not exceed the wheel's marked maximum. Wheels that sound cracked must not be used, wheels must fit freely on the spindle with proper clearance, and contact surfaces must be in good condition.
Key takeaways
- 1910.215(d) is part of OSHA's general industry standards (29 CFR Part 1910, Subpart O).
- OSHA cited it 41 times in the last 3 years, in 41 inspections, with $43,669 in current penalties.
- 1 death is linked to inspections that cited this rule.
- Most citations: AK (9), OR (7), PA (4).
- Related part: 1910.215(d)(3) Surface condition (28 citations).
- Free 5-minute toolbox talk for your crew below.
In this article
What this rule covers
29 CFR 1910.215(d) ("Mounting") is one requirement inside 1910.215 Abrasive wheel machinery, an OSHA general industry standard (Part 1910, Subpart O). It includes 17 sub-paragraphs. The official text below is copied word for word from the Electronic Code of Federal Regulations (eCFR). The numbers, injury cases and training on this page show how OSHA enforces it on real job sites.
Official text
(d) Mounting — 41 citations
(1) Inspection. Immediately before mounting, all wheels shall be closely inspected and sounded by the user (ring test) to make sure they have not been damaged in transit, storage, or otherwise. The spindle speed of the machine shall be checked before mounting of the wheel to be certain that it does not exceed the maximum operating speed marked on the wheel. Wheels should be tapped gently with a light nonmetallic implement, such as the handle of a screwdriver for light wheels, or a wooden mallet for heavier wheels. If they sound cracked (dead), they shall not be used. This is known as the “Ring Test”. Open (d)(1) 13 citations
(i) Wheels must be dry and free from sawdust when applying the ring test, otherwise the sound will be deadened. It should also be noted that organic bonded wheels do not emit the same clear metallic ring as do vitrified and silicate wheels.
(ii) “Tap” wheels about 45° each side of the vertical centerline and about 1 or 2 inches from the periphery as indicated by the spots in Figure O-25 and Figure O-26. Then rotate the wheel 45° and repeat the test. A sound and undamaged wheel will give a clear metallic tone. If cracked, there will be a dead sound and not a clear “ring.”
(2) Arbor size. Grinding wheels shall fit freely on the spindle and remain free under all grinding conditions. A controlled clearance between the wheel hole and the machine spindle (or wheel sleeves or adaptors) is essential to avoid excessive pressure from mounting and spindle expansion. To accomplish this, the machine spindle shall be made to nominal (standard) size plus zero minus .002 inch, and the wheel hole shall be made suitably oversize to assure safety clearance under the conditions of operating heat and pressure.
(3) Surface condition. All contact surfaces of wheels, blotters and flanges shall be flat and free of foreign matter. Open (d)(3) 28 citations
(4) Bushing. When a bushing is used in the wheel hole it shall not exceed the width of the wheel and shall not contact the flanges.
(5) Blotters. When blotters or flange facings of compressible material are required, they shall cover entire contact area of wheel flanges. Blotters need not be used with the following types of wheels:
(i) Mounted wheels.
(ii) Abrasive discs (inserted nut, inserted washer, and projecting-stud type).
(iii) Plate mounted wheels.
(iv) Cylinders, cups, or segmental wheels that are mounted in chucks.
(v) Types 27 and 28 wheels.
(vi) Certain Type 1 and Type 27A cutting-off wheels.
(vii) Certain internal wheels.
(viii) Type 4 tapered wheels.
(ix) Diamond wheels, except certain vitrified diamond wheels.
(6) Multiple wheel mounting. When more than one wheel is mounted between a single set of flanges, wheels may be cemented together or separated by specially designed spacers. Spacers shall be equal in diameter to the mounting flanges and have equal bearing surfaces. When mounting wheels which have not been cemented together, or ones which do not utilize separating spacers, care must be exercised to use wheels specially manufactured for that purpose.
| Material used in construction of guard | Maximum thickness of cutting off wheel | Speed not to exceed | Cutting off wheel diameters | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 6 to 11 inches | Over 11 to 20 inches | Over 20 to 30 inches | Over 30 to 48 inches | Over 48 to 72 inches | ||||||||
| A | B | A | B | A | B | A | B | A | B | |||
| Structural steel (min. tensile strength 60,000 p.s.i.) | 1⁄2 inch or less | 14,200 SFPM | 1⁄16 | 1⁄16 | 3⁄32 | 3⁄32 | 1⁄8 | 1⁄8 | 3⁄16 | 3⁄16 | 1⁄4 | 1⁄4 |
| 1⁄2 inch or less | 16,000 SFPM | 3⁄32 | 1⁄8 | 1⁄8 | 1⁄8 | 3⁄16 | 1⁄8 | 1⁄4 | 3⁄16 | 5⁄16 | 1⁄4 | |
| Minimum material specifications | Diameter of wheel | Minimum thickness of band A | Minimum diameter of rivets | Maximum distance between centers of rivets |
|---|---|---|---|---|
| Inches | ||||
| Hot rolled steel SAE 1008 | Under 8 | 1⁄16 | 3⁄16 | 3⁄4 |
| 8 to 24 | 1⁄8 | 1⁄4 | 1 | |
| Over 24 to 30 | 1⁄4 | 3⁄8 | 11⁄4 | |
| Wheel diameter | Wheel hole diameter | B—Minimum flange diameter | D—Minimun thickness of flange at bore | E—Minimum thickness of flange at edge of undercut | F 1—(D-E) minimum thickness |
|---|---|---|---|---|---|
| 12 to 14 | 4 | 6 | 7⁄8 | 3⁄8 | 1⁄2 |
| 5 | 7 | 7⁄8 | 3⁄8 | 1⁄2 | |
| 6 | 8 | 7⁄8 | 3⁄8 | 1⁄2 | |
| Larger than 14 to 18 | 4 | 6 | 7⁄8 | 3⁄8 | 1⁄2 |
| 5 | 7 | 7⁄8 | 3⁄8 | 1⁄2 | |
| 6 | 8 | 7⁄8 | 3⁄8 | 1⁄2 | |
| 7 | 9 | 7⁄8 | 3⁄8 | 1⁄2 | |
| 8 | 10 | 7⁄8 | 3⁄8 | 1⁄2 | |
| Larger than 18 to 24 | 6 | 8 | 1 | 1⁄2 | 1⁄2 |
| 7 | 9 | 1 | 1⁄2 | 1⁄2 | |
| 8 | 10 | 1 | 1⁄2 | 1⁄2 | |
| 10 | 12 | 1 | 1⁄2 | 1⁄2 | |
| 12 | 14 | 1 | 1⁄2 | 1⁄2 | |
| Larger than 24 to 30 | 12 | 15 | 1 | 1⁄2 | 1⁄2 |
| Larger than 30 to 36 | 12 | 15 | 13⁄8 | 7⁄8 | 1⁄2 |
| 1 For wheels under 11⁄4 inches thick F dimension shall not exceed 40 percent of wheel thickness. | |||||
| A—Diameter of wheel | B—Minimum outside diameter of flanges | C—Radial width of bearing surface | D—Minimum thickness of flange at bore | E—Minimum thickness of flange at edge of recess | |
|---|---|---|---|---|---|
| Minimum | Maximum | ||||
| 1 | 3⁄8 | 1⁄16 | 1⁄8 | 1⁄16 | 1⁄16 |
| 2 | 3⁄4 | 1⁄8 | 3⁄16 | 1⁄8 | 3⁄32 |
| 3 | 1 | 1⁄8 | 3⁄16 | 3⁄16 | 3⁄32 |
| 4 | 13⁄8 | 1⁄8 | 3⁄16 | 3⁄16 | 1⁄8 |
| 5 | 13⁄4 | 3⁄16 | 1⁄4 | 1⁄4 | 1⁄8 |
| 6 | 2 | 1⁄4 | 1⁄2 | 3⁄8 | 3⁄16 |
| 7 | 21⁄2 | 1⁄4 | 1⁄2 | 3⁄8 | 3⁄16 |
| 8 | 3 | 1⁄4 | 1⁄2 | 3⁄8 | 3⁄16 |
| 10 | 31⁄2 | 5⁄16 | 5⁄8 | 3⁄8 | 1⁄4 |
| 12 | 4 | 5⁄16 | 5⁄8 | 1⁄2 | 5⁄16 |
| 14 | 41⁄2 | 3⁄8 | 3⁄4 | 1⁄2 | 5⁄16 |
| 16 | 51⁄2 | 1⁄2 | 1 | 1⁄2 | 5⁄16 |
| 18 | 6 | 1⁄2 | 1 | 5⁄8 | 3⁄8 |
| 20 | 7 | 5⁄8 | 11⁄4 | 5⁄8 | 3⁄8 |
| 22 | 71⁄2 | 5⁄8 | 11⁄4 | 5⁄8 | 7⁄16 |
| 24 | 8 | 3⁄4 | 11⁄4 | 5⁄8 | 7⁄16 |
| 26 | 81⁄2 | 3⁄4 | 11⁄4 | 5⁄8 | 1⁄2 |
| 28 | 10 | 7⁄8 | 11⁄2 | 3⁄4 | 1⁄2 |
| 30 | 10 | 7⁄8 | 11⁄2 | 3⁄4 | 5⁄8 |
| 36 | 12 | 1 | 2 | 7⁄8 | 3⁄4 |
| 42 | 14 | 1 | 2 | 7⁄8 | 3⁄4 |
| 48 | 16 | 11⁄4 | 2 | 11⁄8 | 1 |
| 60 | 20 | 11⁄4 | 2 | 11⁄4 | 11⁄8 |
| 72 | 24 | 11⁄2 | 21⁄2 | 13⁄8 | 11⁄4 |
| 1 Flanges for wheels under 2 inches diameter may be unrelieved and shall be maintained flat and true. | |||||
| Wheel diameter | Wheel hole diameter | B—Minimum flange diameter | D—Minimum thickness of flange at bore | E—Minimum thickness of flange at edge of undercut | F 2—(D-E) minimum thickness |
|---|---|---|---|---|---|
| 20 | 6 | 8 | 1 | 1⁄2 | 1⁄2 |
| 20 | 8 | 10 | 11⁄2 | 3⁄4 | 3⁄4 |
| 24 | 12 | 15 | 2 | 1 | 1 |
| 30 | 12 | 15 | 2 | 1 | 1 |
| 36 | 12 | 15 | 2 | 1 | |
| 1 Flanges shall be of steel, quality SAE 1040 or equivalent, annealed plate, heat treated to R. 25-30. | |||||
| 2 For wheels under 11⁄4 inch thick F dimension shall not exceed 40 percent of wheel thickness. | |||||
| Wheel diameter | Wheel hole diameter | B—Minimum outside diameter of flange | D—Minimum thickness of flange at bore | E—Minimum thickness of flange at edge of undercut |
|---|---|---|---|---|
| 12 to 14 | 5 | 7 | 1⁄2 | 7⁄16 |
| Larger than 14 to 20 | 5 | 7 | 5⁄8 | 7⁄16 |
| 6 | 8 | 5⁄8 | 7⁄16 | |
| 8 | 10 | 5⁄8 | 7⁄16 | |
| 10 | 111⁄2 | 5⁄8 | 7⁄16 | |
| 12 | 131⁄2 | 5⁄8 | 7⁄16 | |
| Larger than 20 to 30 | 8 | 10 | 3⁄4 | 1⁄2 |
| 10 | 111⁄2 | 3⁄4 | 1⁄2 | |
| 12 | 131⁄2 | 3⁄4 | 1⁄2 | |
| 16 | 171⁄2 | 3⁄4 | 1⁄2 | |
| Larger than 30 to 42 | 12 | 131⁄2 | 3⁄4 | 1⁄2 |
| 16 | 171⁄2 | 3⁄4 | 1⁄2 | |
| 18 | 191⁄2 | 3⁄4 | 1⁄2 | |
| 20 | 211⁄2 | 3⁄4 | 1⁄2 | |
| Larger than 42 to 60 | 16 | 20 | 1 | 3⁄4 |
| 20 | 24 | 1 | 3⁄4 | |
| 24 | 29 | 11⁄8 | 7⁄8 | |
| Note: These flanges may be clamped together by means of a central nut, or by a series of bolts or some other equivalent means of fastening. For hole sizes smaller than shown in this table, use table 12. | ||||
| Material used in construction of guard | Maximum thickness of grinding wheel | Grinding wheel diameters | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 3 to 6 inches | Over 6 to 12 inches | Over 12 to 16 inches | Over 16 to 20 inches | Over 20 to 24 inches | Over 24 to 30 inches | Over 30 to 48 inches | |||||||||
| A | B | A | B | A | B | A | B | A | B | A | B | A | B | ||
| Material | 2 | 1⁄4 | 1⁄4 | 3⁄8 | 5⁄16 | 1⁄2 | 3⁄8 | 5⁄8 | 1⁄2 | 7⁄8 | 5⁄8 | 1 | 3⁄4 | 11⁄4 | 1 |
| satis- | 4 | 5⁄16 | 5⁄16 | 3⁄8 | 5⁄16 | 1⁄2 | 3⁄8 | 3⁄4 | 5⁄8 | 1 | 5⁄8 | 11⁄8 | 3⁄4 | 13⁄8 | 1 |
| factory 1 | 6 | 3⁄8 | 5⁄16 | 1⁄2 | 7⁄16 | 5⁄8 | 1⁄2 | 1 | 5⁄8 | 11⁄8 | 3⁄4 | 11⁄4 | 7⁄8 | 11⁄2 | 11⁄8 |
| for | 8 | 5⁄8 | 9⁄16 | 7⁄8 | 3⁄4 | 1 | 3⁄4 | 11⁄8 | 3⁄4 | 11⁄4 | 7⁄8 | 11⁄2 | 11⁄8 | ||
| speeds | 10 | 3⁄4 | 11⁄16 | 7⁄8 | 3⁄4 | 1 | 3⁄4 | 11⁄8 | 3⁄4 | 11⁄4 | 7⁄8 | 11⁄2 | 11⁄8 | ||
| up to | 16 | 11⁄8 | 1 | 11⁄4 | 1 | 15⁄16 | 1 | 17⁄16 | 11⁄16 | 13⁄4 | 13⁄8 | ||||
| 8,000 | 20 | 13⁄8 | 11⁄8 | 13⁄8 | 11⁄8 | 11⁄2 | 13⁄8 | 2 | 15⁄8 | ||||||
| SFPM. | |||||||||||||||
| Cast iron (min. tensile strength 20,000 p.s.i.) Class 20. | |||||||||||||||
| Material | 2 | 1⁄4 | 1⁄4 | 3⁄8 | 5⁄16 | 1⁄2 | 3⁄8 | 5⁄8 | 1⁄2 | 3⁄4 | 5⁄8 | 7⁄8 | 3⁄4 | 1 | 7⁄8 |
| satis- | 4 | 5⁄16 | 5⁄16 | 3⁄8 | 5⁄16 | 1⁄2 | 3⁄8 | 5⁄8 | 1⁄2 | 3⁄4 | 5⁄8 | 7⁄8 | 3⁄4 | 11⁄8 | 7⁄8 |
| factory 1 | 6 | 3⁄8 | 5⁄16 | 1⁄2 | 7⁄16 | 5⁄8 | 1⁄2 | 3⁄4 | 5⁄8 | 7⁄8 | 5⁄8 | 1 | 3⁄4 | 11⁄4 | 7⁄8 |
| for | 8 | 1⁄2 | 7⁄16 | 5⁄8 | 1⁄2 | 3⁄4 | 5⁄8 | 7⁄8 | 5⁄8 | 1 | 3⁄4 | 11⁄4 | 7⁄8 | ||
| speeds | 10 | 1⁄2 | 7⁄16 | 5⁄8 | 1⁄2 | 3⁄4 | 5⁄8 | 7⁄8 | 5⁄8 | 1 | 3⁄4 | 11⁄4 | 7⁄8 | ||
| up to | 16 | 13⁄16 | 11⁄16 | 13⁄16 | 11⁄16 | 1 | 3⁄4 | 11⁄8 | 7⁄8 | 13⁄8 | 1 | ||||
| 9,000 | 20 | 7⁄8 | 3⁄4 | 1 | 3⁄4 | 11⁄8 | 7⁄8 | 11⁄2 | 11⁄8 | ||||||
| SFPM. | |||||||||||||||
| Malleable iron (min. tensile strength 50,000 p.s.i.) Grade 32510. | |||||||||||||||
| Materials | 2 | 1⁄4 | 1⁄4 | 5⁄16 | 5⁄16 | 3⁄8 | 3⁄8 | 1⁄2 | 7⁄16 | 5⁄8 | 1⁄2 | 3⁄4 | 5⁄8 | 7⁄8 | 3⁄4 |
| satis- | 4 | 1⁄4 | 1⁄4 | 1⁄2 | 1⁄2 | 1⁄2 | 1⁄2 | 9⁄16 | 1⁄2 | 5⁄8 | 1⁄2 | 3⁄4 | 5⁄8 | 1 | 3⁄4 |
| factory 1 | 6 | 3⁄8 | 1⁄4 | 3⁄4 | 5⁄8 | 3⁄4 | 5⁄8 | 3⁄4 | 5⁄8 | 13⁄16 | 11⁄16 | 13⁄16 | 11⁄16 | 11⁄8 | 3⁄4 |
| for | 8 | 7⁄8 | 3⁄4 | 7⁄8 | 3⁄4 | 7⁄8 | 3⁄4 | 7⁄8 | 3⁄4 | 15⁄16 | 13⁄16 | 13⁄8 | 1 | ||
| speeds | 10 | 1 | 7⁄8 | 1 | 7⁄8 | 1 | 7⁄8 | 11⁄8 | 15⁄16 | 11⁄8 | 1 | 17⁄16 | 11⁄16 | ||
| up to | 16 | 11⁄4 | 11⁄8 | 11⁄4 | 11⁄8 | 11⁄4 | 11⁄8 | 11⁄4 | 11⁄8 | 113⁄16 | 17⁄16 | ||||
| 16,000 | 20 | 13⁄8 | 11⁄4 | 13⁄8 | 11⁄4 | 17⁄16 | 15⁄16 | 21⁄16 | 111⁄16 | ||||||
| SFPM. | |||||||||||||||
| Steel castings (min. tensile strength 60,000 p.s.i.) Grade V60-30. | |||||||||||||||
| Structural | 2 | 1⁄8 | 1⁄16 | 5⁄16 | 1⁄4 | 5⁄16 | 1⁄4 | 5⁄16 | 1⁄4 | 5⁄16 | 1⁄4 | 3⁄8 | 5⁄16 | 1⁄2 | 3⁄8 |
| steel | 4 | 1⁄8 | 1⁄16 | 3⁄8 | 5⁄16 | 3⁄8 | 5⁄16 | 3⁄8 | 5⁄16 | 3⁄8 | 5⁄16 | 3⁄8 | 5⁄16 | 1⁄2 | 3⁄8 |
| (min. | 6 | 3⁄16 | 1⁄16 | 1⁄2 | 3⁄8 | 7⁄16 | 3⁄8 | 7⁄16 | 3⁄8 | 7⁄16 | 3⁄8 | 7⁄16 | 3⁄8 | 3⁄4 | 1⁄2 |
| tensile | 8 | 1⁄2 | 3⁄8 | 9⁄16 | 7⁄16 | 9⁄16 | 7⁄16 | 9 | |||||||
| strength | 10 | 9⁄16 | 7⁄16 | 5⁄8 | 1⁄2 | 5⁄8 | 1⁄2 | 5⁄8 | 1⁄2 | 5⁄8 | 1⁄2 | 7⁄8 | 5⁄8 | ||
| 60,000 | 16 | 5⁄8 | 9⁄16 | 3⁄4 | 5⁄8 | 3⁄4 | 5⁄8 | 13⁄16 | 11⁄16 | 11⁄16 | 13⁄16 | ||||
| p.s.i.) | 20 | 13⁄16 | 11⁄16 | 13⁄16 | 11⁄16 | 7⁄8 | 3⁄4 | 13⁄16 | 15⁄16 | ||||||
| 1 The recommendations listed in the above table are guides for the conditions stated. Other material, designs or dimensions affording equal or superior protection are also acceptable. | |||||||||||||||
| Overall thickness of wheel (T) | Maximum exposure of wheel (C) |
|---|---|
| 1⁄2 | 1⁄4 |
| 1 | 1⁄2 |
| 2 | 3⁄4 |
| 3 | 1 |
| 4 | 11⁄2 |
| 5 and over | 2 |
| A—Diameter of wheel | B 1—Minimum outside diameter of flange | T—Minimum thickness of flange |
|---|---|---|
| 1 | 5⁄8 | 1⁄8 |
| 2 | 1 | 1⁄8 |
| 3 | 1 | 3⁄16 |
| 4 | 1 3⁄8 | 3⁄16 |
| 5 | 13⁄4 | 1⁄4 |
| 6 | 2 | 3⁄8 |
| 1 Note: Must be large enough to extend beyond the bushing. Where prong anchor or cupback bushing are used, this footnote does not apply. | ||
[39 FR 23502, June 27, 1974, as amended at 43 FR 49750, Oct. 24, 1978; 49 FR 5323, Feb. 10, 1984; 61 FR 9240, Mar. 7, 1996]
Source: eCFR, text current as of 2026-10-15. Read all of 1910.215.
Injuries linked to this rule
1 death is linked to inspections where OSHA cited 1910.215(d).
At 9:00 a.m. on January 19, 2024, two employees (Employee #1 and Employee #2) were setting up the site to create another stack of steel pipes (30 inches in diameter by 40 feet long, weighing over 2,000 pounds each.) The employees removed the chock block…
Where and how often it was cited
| Year | Citations |
|---|---|
| 2023 | 2 |
| 2024 | 15 |
| 2025 | 11 |
| 2026 | 13 |
Top states: AK (9), OR (7), PA (4), IN (4), NV (3)
Largest penalties
| Employer | Location | Penalty for this rule |
|---|---|---|
| TALLADEGA FOUNDRY & MACHINE CO., INC. | TALLADEGA, AL | $8,441 |
| GOLDEN ALASKA SEAFOODS | DUTCH HARBOR, AK | $5,958 |
| TRIDENT SEAFOODS CORPORATION | DUTCH HARBOR, AK | $5,065 |
| GLACIER FISH COMPANY LLC | DUTCH HARBOR, AK | $5,065 |
| CAESARS ENTERTAINMENT, INC | RENO, NV | $4,148 |
Free toolbox talk
A 5-minute crew talk on 1910.215(d), plus alerts when this rule changes. Free.
OSHA interpretation letters
Related parts of this rule
- 1910.215(d)(3) Surface condition 28 citations
- 1910.215(d)(1) Inspection 13 citations
Get your crew competent
Trainers on Black Belt Safety: Marc Harvey, Dana Reyes
Trainers and suppliers: feature your business on this rule for $25/month.
Frequently asked questions
What is the ring test?
Gently tapping a dry wheel with a light nonmetallic tool; a sound wheel gives a clear metallic tone and a cracked one sounds dead.
What must be checked before mounting?
The spindle speed, to be sure it does not exceed the maximum operating speed marked on the wheel.
Can a wheel that sounds dead be used?
No. Wheels that sound cracked must not be used.
About this page
Sources
- 29 CFR 1910.215 (eCFR), text current as of 2026-10-15
- U.S. Department of Labor enforcement data: OSHA inspections, citations and accident records, copied nightly; data as of 2026-10-22
3-year window. Federal OSHA only; state-plan rules are not counted. Plain-language text is a summary, not legal advice; the official text controls. Black Belt Safety is not part of OSHA or the Department of Labor.