Nails, Screws, Bolts, and Other Fasteners - Carpenter's and Builder's Math, Plans, and Specifications - page 13

1. When using box nails in lumber of medium hardness, the
penny of the nail should not be greater than the thickness,
in eighths of an inch, of the board into which the nail is being
driven.

2.

In very soft woods, the nails may be one penny larger, or in
some cases, two pennies larger.

3.

In hard woods, nails should be one penny smaller.

4.

When nailing boards together, the nail point should penetrate
within 1

/ 4 inch of the far side of the second board.
The kind of wood is, of course, a big factor in determining the
size of nail to use. The dry weight of the wood is the best basis for the
determination of its grain substance or strength. The greater its dry
weight, the greater its power to hold nails. However, the splitting
tendency of hard wood tends to offset its additional holding power.
Smaller nails can be used in hard lumber than in soft lumber (see
Figure 1-12). Positive rules governing the size of nails to be used as
related to the density of the wood cannot be laid down. Experience
is the best guide.

10 d

7 d

SOFT
WOOD

HARD
WOOD

8 / 8 (1 IN.)

Figure 1-12 Application of rules 2 and 3 in determining the
proper size of nail to use.

Table 1-5 shows the approximate number of wire nails per pound.

Driving Nails
In most cases, it is not necessary to drill pilot holes for nails to avoid
splitting the wood. However, in some instances it is advisable to
first drill holes nearly the size of the nail before driving, to guard