ASTM A194 Grade 2H Nut Dimensions: ASME B18.2.2 Heavy Hex
ASTM A194/A194M-20a takes nut dimensions from ASME B18.2.2 for inch nuts and ASME B18.2.4.6M for metric nuts (3.1.5). Nuts are hexagonal, in the hex or heavy hex series as ordered; unless otherwise specified the heavy hex series is used, and nuts are double chamfered or have a machined or forged washer face, at the manufacturer's option (9.1). For a 1 in. heavy hex nut, ASME B18.2.2 Table 10 gives 1.575 to 1.625 in. across flats and 0.956 to 1.012 in. thickness.
ASME B18.2.2 Heavy Hex Nut Dimensions (Inch Series)
| Nominal Size | Width Across Flats F (in) | Thickness H (in) | Thread |
|---|---|---|---|
| 1/4 | 1/2 | 15/64 | 1/4-20 UNC |
| 5/16 | 9/16 | 19/64 | 5/16-18 UNC |
| 3/8 | 11/16 | 23/64 | 3/8-16 UNC |
| 1/2 | 7/8 | 31/64 | 1/2-13 UNC |
| 5/8 | 1-1/16 | 39/64 | 5/8-11 UNC |
| 3/4 | 1-1/4 | 47/64 | 3/4-10 UNC |
| 7/8 | 1-7/16 | 55/64 | 7/8-9 UNC |
| 1 | 1-5/8 | 63/64 | 1-8 UN |
| 1-1/8 | 1-13/16 | 1-7/64 | 1-1/8-8 UN |
| 1-1/4 | 2 | 1-7/32 | 1-1/4-8 UN |
| 1-3/8 | 2-3/16 | 1-11/32 | 1-3/8-8 UN |
| 1-1/2 | 2-3/8 | 1-15/32 | 1-1/2-8 UN |
| 1-3/4 | 2-3/4 | 1-23/32 | 1-3/4-8 UN |
| 2 | 3-1/8 | 1-31/32 | 2-8 UN |
| 2-1/4 | 3-1/2 | 2-13/64 | 2-1/4-8 UN |
| 2-1/2 | 3-7/8 | 2-29/64 | 2-1/2-8 UN |
| 2-3/4 | 4-1/4 | 2-45/64 | 2-3/4-8 UN |
| 3 | 4-5/8 | 2-61/64 | 3-8 UN |
| 3-1/4 | 5 | 3-3/16 | 3-1/4-8 UN |
| 3-1/2 | 5-3/8 | 3-7/16 | 3-1/2-8 UN |
| 3-3/4 | 5-3/4 | 3-11/16 | 3-3/4-8 UN |
| 4 | 6-1/8 | 3-15/16 | 4-8 UN |
Mechanical Properties
| Property | Value |
|---|---|
| Material | Carbon Steel Q&T (UNS K04100) |
| Hardness | 248-352 HBW (24-38 HRC) |
| Proof Load (1-inch 8UN) | 140,000 lbf min |
| Temperature Range | up to 800°F (427°C) |
This table is flagged for technical correction. ASTM A194/A194M-20a gives Grade 2H 248 to 327 HB or 24 to 35 HRC up to 1-1/2 in. or M36 (Table 2), a heavy hex proof stress of 175 000 psi [1205 MPa] (Table 5) and a 1 in. heavy hex proof load of 106 000 lbf (Table 3). Proof loads are not design loads.
Thread Series
- Up to and including 1 in.: UNC series, Class 2B fit (9.2.1).
- Over 1 in.: UNC or 8 UN series, Class 2B fit; the 8 UN series is furnished unless otherwise specified (9.2.2).
- Metric: coarse thread series, tolerance 6H (9.2.1, 9.2.2).
- Threads follow ASME B1.1 or B1.13M and are gauged to ASME B1.2 and B1.13M (9.2).
Related Pages
Grade 2H product page · ASME B18.2.2 heavy hex nuts · heavy hex jam nuts · Grade 2H substitutes · ASTM A194 PDF · A194 hub.