Advice for oak table part 1

[p111dom]

I've been asked by someone who found me on this forum actually to make them a simple dining table. However the location has me a little worried. The table is to be used as a multi purpose table in the clients home office which is a summer house (log cabin style) at the bottom of his garden. I have issues with two things. Firstly the issue of wood movement. While this building is heated when being used it's not when vacant and it isn't insulated. Standing in it you could feel the humidity in the air. Of course with this being Scotland the temperature in the winter at night can be as low as -17C. This could lead to a situation where the space is being heated to say 20C and then left to rapidly cool by 37C with in a couple of hours. I worried the that this may make the table warp to the extent that it walks it's way into the garden. Anyone else got any experience with something similar?

Please see the finishing section for part 2.

 

[marcus]

In spite of the extreme conditions you will probably be OK so long as you use seriously strong traditional joinery, and they are happy with a fairly rustic, solid, well braced design.

Through wedged tenons, etc, and very strong cleats for the top. And breadboard ends. Also it might help to make the top quite thin so that it doesn't pull too much if it wants to move.

Think of the wooden boats that live all year round in those parts, and survive perfectly happily, full of wooden furniture and fittings - and intermittently immersed in water too! They often have stoves in them which will heat up the inside temporarily.

If the customers are wanting a more delicate sort of design I would worry though!

In any case if it was me I'd get them to sign a disclamier that some movement is to be expected in those conditions. So long as nothing breaks (and made strongly there's no reason why it should), this is known as "character". All quality antiques have it - lovely!

Cheers.

Marcus

 

[p111dom]

That wasn't really the methods of joinery I was thinking about. I would mainly be using the Domino as it's pretty difficult to cut a tennon on a rail 5 or 6 feet long. All rails and top are 30mm thick oak 85 mm deep with the top held on with buttons spaced at minimum intervals of 10 inches. Slightly tapered legs 3 inches square. It would lie somewhere between fine and rustic. I was going to brace the top more than I normally would. Do you think that would be ok. Glue would be Titebond 2.

 

[MikeG.]

P111Dom,

I would design this very simply, and be very cautious of having any cross-grain situations. I wouldn't glue braces under the table-top, for instance.......and whilst breadboard ends would hold everything nice and straight, they would have to be carefully designed and made to allow for a lot of movement.

Don't let this put you off, it is very do-able. As long as your client (I think I remember how the contact happened!) is aware that the circumstances of the location are going to have a strong bearing on the design.

Good luck with it. How about posting a sketch of your proposals?

Mike

 

[marcus]

I would mainly be using the Domino as it's pretty difficult to cut a tennon on a rail 5 or 6 feet long.

This could be a time to rise to the challenge! Shoulders by hand or on the table saw, cheeks on the bandsaw is one way to go. I wouldn't trust dominos for this. Pegged tenons would probably be OK if you wanted to avoid the look of through wedged ones, although not quite as strong.

The bracing I was referring to is some sort of arrangement of stretchers for the legs. I think if you left the legs floating free at the bottom it really might wander off into the garden!

Cheers

Marcus

 

[p111dom]

I think I'll just have to go for it. There won't be any cross grain situations other than the rails going into the legs but because they are only 85mm deep expansion will be minimal. I'm limited to the tennon depth by the fact that the tennons from the ends and the sides will meet in the middle. By the time I've cut them down and either mitred them or lap jointed them I would have thought that the strength differentlal would be minimal. Anyone who's dry fitted together a peice with dominos should be able to testify how strong they are even without glue. Sometims getting them apart again can be a problem. I'll add some additional 45 degree supports around the corners which will beef up the domino's and help to keep everything square if there is any uneven movement across the top. For the legs I can't have braces or strechers at the bottom. How would you get a chair underneath? I think I'll try and counter act any warping by making the legs out of two pieces rather than one reversing the growth rings so if they do move they will be in opposite directions and as long as the glue holds they will keep eachother in check. I hear what you are saying about tennons on the bandsaw but again manovering a 6 foot long piece in to the blade seems like asking for trouble especially when I have a Domino sitting in the cupboard. One slip and the fix is alot of money. I wonder if I have to avoid making the piece too ridgid? If it's got a little bit of flex then if something does warp slightly it's more likely to settle down onto four legs under it's own weight but not if it's too strong. Hummm...