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
to grain (psi)

Tension parallel
to grain (psi)

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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