Screw and nail holding strength by species
Ultimate withdrawal load in pounds per inch of penetration, for a #8 and a #10 wood screw, a 16d common nail and a 3/8" lag. Laboratory loads, not design values — divide by five before you build to one.
| Species | Specific gravity | #8 screw | #10 screw | 16d nail | 3/8" lag | #10 at a 5× factor |
|---|---|---|---|---|---|---|
| Hickory | 0.72 | 1335 lb | 1546 lb | 559 lb | 2181 lb | 309 lb |
| White oak | 0.68 | 1191 lb | 1379 lb | 485 lb | 2002 lb | 276 lb |
| Red oak | 0.63 | 1022 lb | 1184 lb | 401 lb | 1785 lb | 237 lb |
| Hard maple | 0.63 | 1022 lb | 1184 lb | 401 lb | 1785 lb | 237 lb |
| Sapele | 0.62 | 990 lb | 1147 lb | 385 lb | 1743 lb | 229 lb |
| Ash | 0.6 | 927 lb | 1074 lb | 355 lb | 1659 lb | 215 lb |
| Walnut | 0.55 | 779 lb | 902 lb | 285 lb | 1456 lb | 180 lb |
| Soft maple | 0.54 | 751 lb | 870 lb | 273 lb | 1417 lb | 174 lb |
| Cherry | 0.5 | 644 lb | 746 lb | 225 lb | 1262 lb | 149 lb |
| Mahogany | 0.5 | 644 lb | 746 lb | 225 lb | 1262 lb | 149 lb |
| Douglas fir | 0.48 | 593 lb | 687 lb | 203 lb | 1187 lb | 137 lb |
| Poplar | 0.42 | 454 lb | 526 lb | 145 lb | 972 lb | 105 lb |
| White pine | 0.35 | 315 lb | 365 lb | 92 lb | 739 lb | 73 lb |
| Cedar | 0.32 | 264 lb | 305 lb | 74 lb | 646 lb | 61 lb |
Reading it
- From the USDA Wood Handbook's withdrawal equations: 15,700·G²·D for a wood screw, 7,850·G^2.5·D for a nail and 7,450·G^1.5·D^0.75 for a lag, per inch of penetration.
- Every figure but the last column is an ultimate load from a test machine on clear, conditioned wood. The last column is the same #10 after dividing by five, which is the common factor for a static load — a sustained or overhead load wants more.
- Side grain only. End-grain withdrawal runs at roughly three quarters of this at best and is unreliable enough that the Wood Handbook advises against designing for it.
- Specific gravity is squared for a screw, so the spread down this table is the point: the same screw holds about four times as much in the top row as in the bottom. These are species averages — a good bet across a stack of boards and no promise about the one in your hand.
- Nothing here predicts the fastener itself snapping or the wood splitting, and nothing here governs a structural connection. That is the NDS, the hardware maker, and an engineer.
For the case this table does not cover
- Screw and nail holding strength
What a screw, nail or lag holds before it pulls out, by species and by how deep the thread goes.
- Screw length
How long a screw to put through one board into another, and whether the tip comes out the far side.