Loose Tenons

[wizer]

I have always wondered about loose tenons. If you're not doing through m&t's (or even if you where) Why would you not use loose tenons? To my mind you save on wood (using offcuts and scrappy bits for tenon stock).

Is this a correct way of thinking? Is there a reason why Loose tenons don't seem to be used nearly as much?

Just wondering, for the sake of conversation..

[engineerone]

you would i guess say that the festo domino is a loose tenon

having recently made a number of m/t's i just found it easier to do it the "proper" old fashioned way. i think from a personal point of view the problem would be making sure the loose tenons are actually cut in the right way to give you the proper grain orientation to ensure the best strength,

many people use ply for loose tenons and of course biscuits could also be called loose tenons. so i guess people do use them more than you might think. but would seem to me that people would prefer to use a composite ie ply for a loose tenon.

paul

[Scrit]

The "proper way" in door and window construction involves wedged or foxed tenons to secure the joint. In that case even if the glue joint fails completely the wedges alone are normally sufficient to hold the structure together, as I'm certain Jacob will attest. I suppose that the biscuit is a sort of half way house between a wedged tenon and a loose tenon in that it swells in contact with a water-based glue to effectively "lock" the joint, so that even if the glue fails the biscuit probably won't. Whilst I'm an adherent of modern glues, few if any have been long enough to demonstrate that they will survive a hundred or more years in an exterior environment and loose tenons and Dominos do depend on the strength of the glue joint alone (not always good if you are glueing cross grain joints due to differential expansion/contraction), therefore I'm one of those sceptics who thinks that loose tenons may have their place, but only for interior or short-lifespan exterior items. The clincher for me is that the standard Domino biscuit (like the Lamello biscuits) is made from beech, a species totally unsuitable for exterior use.

Scrit

[thallow]

I used loose tenons on this:



purely from a practical viewpoint (ie no morticiser or bandsaw at th time - I simply used my router table with a jig to make the mortice (a la domino) and then made a 'peg' out of the same piece of oak that needed to be hammered home into the mortice; the words eggs, granny & suck spring to mind but the pegs were made from one length of aok and then just chopped to size. Worked a treat and will use it again whilst I get my M&T up to speed!

[wizer]

Cheers guys. I wonder what the best material is for loose tenons? Beech? Ply? or does it have to match the timber it's going in to? (I suspect not)

[Scrit]

May 5, 2008 19:08:55 GMT wizer said:

Cheers guys. I wonder what the best material is for loose tenons? Beech? Ply? or does it have to match the timber it's going in to? (I suspect not)

If your project is going to be indoors it can be almost anything you like, really. Probably better if it is the same material as the main structure though, as that will move at the same rate as the rest of the timber.

Scrit