On Sunday, November 18, 2018 at 3:47:48 PM UTC, John Rumm wrote:
On 17/11/2018 15:36, NY wrote:

I have a wooden chair with four legs that fit into the seat, with front
and back legs on each side held from splaying out by a fore-and-aft
cross-brace; those two braces are themselves joined by a side-to-side
brace. On one side, the braces have come loose from the holes in the
legs, making the chair rickety. I tried gluing them with PVA glue but
the glue joint broke almost immediately (after letting it set for
several hours).

The only glue that will cope with joints that are not snug fitting is
epoxy. PVA has not gap filling capacity.

I don't want to have to unglue and re-glue any of the other joints (in
case I make things worse). What is the best glue to use for sticking a
joint where one wooden piece fits into a hole in the side of another? I
can extract the cross-brace by about 10 mm, but there isn't enough play
to remove the brace totally to line the hole with glue, so I have to
rely on straining the joints to expose as much of the ends of the brace,
smearing glue around the exposed part of the brace (at both ends) and
then pushing it back together.

Disassembly, clean-up and re-gluing is probably the best approach.

For really good pull out resistance on a mortice and tenon joint, you
would need a wedged or "foxed" tenon. With chair leg joints you normally
have blind mortices, and so need hidden wedges.

Kind of like a round version of :

http://wiki.diyfaq.org.uk/index.php/...Blind_Mortices

(typically the mortice in the leg is widened toward its base, and then
the tenon on the stretcher, has a saw kerf cut down it across its
diameter. The wedge is then placed into the kerf once everything is
glued up, and the joint assembled and driven home)


In some chairs, where the holes in the elm seat go righ through, you can see that kind of wedge. But in others I think the motice in the seat don't go all through. Did they sometimes hide a wedge inside the mortice before driving the leg in? That would be neat. I'm talking here about those typical bentwood chairs I suppose.