BS 1804-3
BS 1804-3 specifies metric parallel and taper steel dowel pins with screw threads for extraction. The drawing distinguishes the four pin forms covered by the standard.
Pin types and dimensional references
| Type | Pin form | Extraction feature | Principal dimensions |
|---|---|---|---|
| A | Parallel | External thread | D, L, thread |
| B | Parallel | Internal thread | D, L, thread |
| C | Taper | External thread | D, L, thread |
| D | Taper | Internal thread | D, L, thread |
Dimension references
| Symbol | Dimension | Unit |
|---|---|---|
| D | Nominal pin diameter | mm |
| L | Overall pin length | mm |
| Thread | Extraction thread size and depth | Metric |
Type B metric extraction thread schedule
| Nominal pin diameter (mm) | Internal thread | Thread depth (mm) |
|---|---|---|
| 3 | M2 | 3.5 |
| 4 | M2.5 | 4 |
| 5 | M3 | 5 |
| 6 | M4 | 6 |
| 8 | M5 | 8 |
| 10 | M6 | 10 |
| 12 | M8 | 12 |
| 16 | M10 | 16 |
| 20 | M12 | 18 |
| 25 | M16 | 24 |
Note: The Type B tapping schedule is a published supplier range for metric BS 1804-3 extraction dowels. Check the specified standard edition and product drawing before using it for manufacture; this is not the full standard size schedule.