Holes should always be bored when there is any chance of splitting, or when slender nails are driven into hard wood (lest they bend), but remember that the hole, particularly in the inner piece, should not be quite as large as the nail. With nails having large heads it does not matter in hard wood if the holes in the outer piece are about as large as the nails, provided the latter drive tightly into the inner piece.
Fig. 605.
The hole made by a brad-awl is better, when it does not split the wood, than one made by a bit or drill, because it does not remove the wood but merely presses it aside, so that when the nail is driven the fibres tend to spring back to their original position and close in around the nail, helping to hold it in place.
In driving the old-fashioned nails, which have two sides parallel, while the other two incline toward the point or taper, they should be used on the same principle on which you use the brad-awl. If placed the other way, the wedge shape of the nail will tend to separate the fibres and split the wood (Fig. 605). With nails having two sides smooth and two rough, as you pick them up you can tell by the fingers which way to hold them, the rough sides going across the grain and the smooth sides with it.
Nails will drive into hard wood easier if you touch the points to grease, tallow, lard, or soap.
Fig. 606.
Fig. 607.