Common thread and fastener sizes found on Classic motorcycles.
| American AF /SAE UNF UNC | ||||||
|---|---|---|---|---|---|---|
| spanner jaw (in) | bolt diam (in) | threads per inch | bolt diam (mm) | |||
| SAE Regular | SAE Fine | UNF | UNC | |||
| 1/8 | 48 | 40 | 3.17 | |||
| 7/16 | 1/4 | 36 | 28 | 28 | 20 | 6.35 |
| 1/2 | 5/16 | 32 | 24 | 24 | 18 | 7.93 |
| 9/16 | 3/8 | 32 | 24 | 24 | 16 | 9.53 |
| 5/8 | ||||||
| 11/16 | 7/16 | 28 | 20 | 20 | 14 | 11.11 |
| 3/4 | 1/2 | 28 | 20 | 20 | 13 | 12.70 |
| 7/8 | 9/16 | 24 | 18 | 18 | 12 | 14.28 |
| 15/16 | 5/8 | 24 | 18 | 18 | 11 | 11.00 |
| 1 1/8 | 3/4 | 20 | 16 | 16 | 10 | 19.05 |
| Metric ISO | |||||
|---|---|---|---|---|---|
| spanner jaw (mm) | bolt diam (mm) | pitch (mm) | tpi | ||
| Fine | Coarse | F | C | ||
| 10 | 6 | 0.75 | 1.00 | 33.86 | 25.4 |
| 11 | 7 | --- | 1.00 | --- | 25.4 |
| 13 | 8 | 1.00 | 1.25 | 25.4 | 20.32 |
| 17 | 10 | 1.00* 1.25 |
1.50 | 25.4 20.32 |
16.93 |
| 19 | 12 | 1.25* | 1.75 | 20.32 | 14.51 |
| 22 | 14 | 1.50 1.25* |
2.00 | 16.93 | 12.70 |
| 24 | 16 | --- | 2.00 | ---- | 12.70 |
| 27 | 18 | *1.50 | 2.50 | 16.93 | 10.16 |
| * spark plug threads | |||||
| Cycle | |
|---|---|
| bolt diam (in) | tpi |
| 1/8 | 40 |
| 1/4 | 26 |
| 5/16 | 26 |
| 3/8 | 26 |
| 7/16 | 26 or 20 |
| 1/2 | 26 or 20 |
| 9/16 | 26 or 20 |
| 5/8 | 26 or 20 |
| 11/16 | 26 or 20 |
| 3/4 | 26 or 20 |
| 7/8 | 24 or 20 |
| 1 | 24 |
| BSF | |
|---|---|
| bolt diam (in) | tpi |
| 1/4 | 26 |
| 5/16 | 22 |
| 3/8 | 20 |
| 7/16 | 18 |
| 1/2 | 16 |
| 9/16 | 16 |
| 5/8 | 24 |
| 11/16 | 14 |
| 3/4 | 12 |
| 7/8 | 11 |
| 1 | 10 |
| BSW | |
|---|---|
| bolt diam (in) | tpi |
| 1/8 | 40 |
| 1/4 | 20 |
| 5/16 | 18 |
| 3/8 | 16 |
| 7/16 | 14 |
| 1/2 | 12 |
| 9/16 | 12 |
| 5/8 | 11 |
| 11/16 | 11 |
| 3/4 | 10 |
| BSP | |
|---|---|
| tube bore (in) | tpi |
| 1/8 | 28 |
| 1/4 | 19 |
| 3/8 | 19 |
| 1/2 | 14 |
| BA | |
|---|---|
| size no. | pitch (mm) |
| 0 | 1.00 |
| 1 | 0.90 |
| 2 | 0.81 |
| 3 | 0.73 |
| 4 | 0.66 |