6561Re: Treenailing? WAS: Grain in joints and finishing questions
- Jul 1, 2006--- In email@example.com, "msgilliandurham"
>Treenails are basically wooden nails. There really isn't much
> > I'm guessing from the context that "treenailing" is using some kind
> of narrow pegs as if they were metal nails -- but could you
> elaborate, please?
difference between pegs and treenails, except the latter sounds
cooler. It's more the way they are used that's different: Treenailing
implies (to me at least) fixing one board atop another, whereas
pegging is a way to lock mortise and tenon joints together.
Note well, however, that these terms aren't rigidly defined, so other
writers may use them in different ways. (I think in boatbuilding a
treenail means a peg with a head, like an unthreaded bolt, so it can't
be pulled through a board. But what I know about boatbuilding
wouldn't cloud your vision if it was in your eye, so...)
>When pegging a wide, cross-grain mortise-and-tenon joint, you can
> Elongated how, please?
elongate the peg holes in the tenon so that the tenoned board can move
without opening up the joint. For example, a breadboard end might be
fixed with three (or five) pegs. The center one is done the usual way
(i.e. drawbored - the hole in the tenon is offset slightly toward the
shoulder, relative to the holes in the mortise) so all movement is
away from the center. The other holes (also drawbored) can be
elongated slightly across the grain, so that the tabletop can shrink
or swell without cracking.
I don't think this was ordinarily done much in the MA because thick
riven planks don't actually move that much, and because the pegs are
flexible enough to accommodate some movement. But I wouldn't be
surprised to see it on clamped-front chests or tabletops in the late MA.
> Also, the book which started my thinking about this issue, saysThis is true only if the board is losing moisture and shrinking. The
> that "when assembing a box or drawer [this is one where the grain of
> all four sides is the same] turn the boards so tha annuual rings
> curve out [...] The board's natural tendency to cup will keep the
> corner joints tight at the edges."
outside of a log shrinks more than the inside, so it cups opposite the
curvature of the rings. It's also only true for plainsawn (flatsawn)
lumber. Quartersawn lumber has little tendency to cup.
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