wrote in message
oups.com...
Does having a precise exact fitting loose tenon add much to the
strength of the joint? How much extra gluing surface to you get from
that corner compared to the flat sides of the loose tenon? Not much.


While the loose tennon is far superior and stronger than most other joints
and I agree that a tennon not filling the width is probably not too
important, to answer your question about the extra gluing surface, Because
the sides are round they will add more surface area than if all sides were
flat.
Taking the 10 x 24 x 50 domino tennon for an example, the short sides
collectively have a length of 31.4mm as compared to both wide sides having
collectively 48mm. So the narrower sides are a significant amount of the
possible glue surface.
IMHO this does not add much strength to keep the tennon from sliding in the
mortise as much as it would to keep the tennon from pulling out of the
mortise.