Penny nails are sized based on the 'penny' system, where each increase in penny size corresponds to a specific length increase. The term "penny" in nail sizing has origins in old British currency, where the abbreviation "d" for the denarius (an old Roman coin) became associated with the old British penny.
Here's a breakdown of how penny size translates to nail length, using information from the reference:
Penny Nail Sizes and Lengths
| Penny Size | Length (inches) | Length (cm) |
|---|---|---|
| Base Size | 1 inch | 2.54 cm |
| +1 | + 1/4 inch | + 0.635 cm |
| 2d | 1 ¼ | 3.175 cm |
| 3d | 1 ½ | 3.81 cm |
| 4d | 1 ¾ | 4.445 cm |
| 5d | 2 | 5.08 cm |
| 6d | 2 ¼ | 5.715 cm |
| 7d | 2 ½ | 6.35 cm |
| 8d | 2 ¾ | 6.985 cm |
Key Points:
- The base size is 1 inch (2.54 cm).
- Nail sizes go up ¼-inch (1.905 cm) for each penny from 2d onwards.
- For example, a 7-penny nail is 2 ¼ inches (5.715 cm) long.
Summary
In essence, the length of penny nails is determined by their "penny" designation. Each "penny" size increments the nail's length by ¼ of an inch from the base, which helps in selecting the appropriate nail for different woodworking or construction projects.
