Great figure. 14d especially, as it is a form of joinery that would
hardly occur to most of us, yet makes perfect sense to the medieval.
All of these methods avoid the problem of cross-grain glue joint
failure, which is pretty much inevitable. I was surprised to discover
how much movement a pinned joint can accommodate. There are plenty of
medieval examples of pinned cross-grain joinery, and they don't all
involve elongated holes (as in modern breadboard ends). For example, in
clamped-front chests of the XIIIc, the lid is often fixed to battens
with treenails - wooden pegs driven in just like nails. You'd think
this would not hold up long-term, but it does.
Sir Stan is correct that many, if not most, of these triptych panels
were decorated on both sides. Most of the time, the triptych was closed
up, and the painting on the "back" was exposed to view. This painting
was nearly always simpler than what was on the inside, frequently just
armory of the donor; in some cases portraits of saints, done in muted
colors or grisaille. It was the "everyday" appearance. It didn't seem
to bother the medievals to have exposed fasteners on that side; nails,
clips, wedges, etc. There may or may not have been a moulding applied
to the "back" side. Basically it was not considered the "pretty" part.
This is almost the opposite of our modern expectation - the side most
often viewed should look the best!
One other thing that made your glue joint failure inevitable was the use
of flatsawn lumber for the panels. Not only does this move more than
quartersawn, but it moves differently: it bows as it moves. Panels for
paintings should always be made from quartersawn wood.
Nice job with the beveled moulding on the bottom rail. Some (most?) of
these mouldings were actually M&T framed; I did that with the side-panel
tracery on the West Kingdom Court Thrones and found it a bit tricky to
cut, but a nifty joint when done. I have photos if anybody's interested.
On 6/27/2011 6:06 PM, sdhunter3 wrote:
> The omitted figure: (Fig. 14a-d). Has been uploaded to my Triptych directory.
> There are several examples of triptychs with decoration and molding applied to the outside surface of the panels.