I’ve gotten some questions (and derision) about a photo we posted on Instagram from “The Anarchist’s Design Book,” that shows assembling a six-board chest with rosehead nails.
In the photo I have the clamps oriented to prevent splits. And that’s where the questioning begins.
Question: Why aren’t the clamps oriented across the width of the top board? That would seem to prevent splits.
Answer: I’m not trying to prevent the top board from a splitting. A properly sized pilot hole will do that. I’m trying to prevent the bottom board from splitting.
When you use cut or wrought nails, the depth of the pilot hole should be only half or two-thirds the length of the nail. This makes the nail do some of the work and is what gives these nails their excellent holding power.
However, in soft woods (such as this white pine) you can sometimes rupture the fibers because – and this is important – the fibers can do one of two things: They can compress or they can split.
If I apply a clamp across the bottom part of this joint, the fibers will compress when I drive the nail in. If I don’t, they are likely to rupture.
After I remove the clamps, the fibers remain intact. The fibers around the nails are compressed and the bonds between the fibers remain.
Compression is your friend, not only in nailing, but in dovetailing, drawboring and in making joints for stick chairs.
— Christopher Schwarz