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
With that in mind, Chris, would it be better (or provide additional assistance) if you just clamped both sides of the bottom board with one clamp? Just applying pressure to both faces of the board? Do you ever have blowouts on the inside face of the bottom board? Maybe that would prevent those, as well?
Understandably, that would be difficult to do towards the middle of a board, but maybe clamping cauls, then? Or would that be too much trouble?
(Apologies; I’m sure it’s difficult to know what to do with me when I actually ask a legitimate question instead of posting snarcasm.)
(And yes, I’m quite aware of my word use. Hahaha… there are times when you can say “actually” and it works.)
One clamp on the outside has always been enough in my experience.
However, if things started splitting on the inside, I’d clamp both sides, using a caul if necessary.
The missing link is that there is a rebate on the underside of the top board. I must admit that I though it looked funny when I saw this posted on IG (and derided in 6 minutes or less) but this makes perfect sense as a clamp would be unlikely to help when nailing in the middle of a wide board (as opposed to near the edge) anyway.
“Compression is your friend, not only in nailing, but in dovetailing, drawboring and in making joints for stick chairs.” – Also snake bites!
And, depending on how carp the pine board is, it also stops you from popping out a little piece of the face board on the end too DAMHIK.