Q: We are exploring the possibility of changing species. It is critical that we have good tension and compression strength as well as good nail holding. Can you give me comparison values for the species listed below?
A: I went to the U.S. Dept. of Agriculture's Wood Handbook (Ag Handbook No. 72) and obtained the following values. Keep in mind that a good predictor of strength is the density of the wood. Density of wood is usually measured relative to the density of water and the ratio is called the specific gravity (SG). The following values are for clear wood at 12 percent MC. For nail holding, a 6d nail was used and was pulled straight out.
Species SG Compression parallel to grain (psi) Tension parallel to grain (psi) Nail holding (psi)
Species | SG | Compression parallel | Tension parallel | Nail holding (psi) |
Hard maple | 0.63 | 15,800 | 7,830 | 279 |
Soft maple | 0.47 | 8,900 | 5,200 | 134 |
Yellow birch | 0.62 | 16,600 | 8,170 | 268 |
White birch | 0.55 | 12,300 | 5,690 | 199 |
American beech | 0.64 | 14,900 | 7,300 | 291 |
White ash | .60 | 15,000 | 7,410 | 247 |
Red oak | 0.63 | 14,300 | 6,760 | 279 |
White oak | 0.68 | 15,200 | 7,400 | 338 |
Hickory (true) | .072 | 19,200 | 8,940 | 390 |
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