Another wood movement question

[Alex Zeller]

So I'm thinking about building a hope chest with a curved top. Kind of like a steamer chest but I want the top to be solid wood. Most of the steamer chests I've seen look more like raised panels Basically it would be coopering. I'm thinking of using quarter sawn white oak since I've never used it before a project and I believe it'll be more stable. I borrowed this picture on the internet.

lid.jpg
How would the top be connected to the ends? I'm assuming that with the wood going different directions it would be an issue. I'm guessing that it'll be about 40" x 20" x 20" ish. I wouldn't mind adding a couple supports that match the ends in the middle just to add to it visually when the lid is opened. The ends would be flush, not the top overhanging like in the pictures. I'm still in the early phase of trying to decide what I want to build but how the lid is made will be the challenge for me.

lid2.jpg

[John TenEyck]

Interesting problem. The first thing that comes to mind is to screw through the end fillers into the coopered top, only in the center and let the rest of it float in sliding dovetails. I think you'd only need a short section of dovetail near each end of the fillers. If the radius is not constant or symmetrical the dovetails could have a tenon on the other side that fits into a dado in the fillers.

Another option would be to make a curved cleat along the inside edge of the fillers and screw through slotted holes into the coopered top. That would be the easiest approach I think.
John

[Robert Engel]

I thought of a couple ideas:

A tenon in the bottom of the top that goes into the batten & has a slotted hole which is draw bored.
&
Pre-cut a dovetail slot in a few of the slats insert the tenon, sized slightly narrower than the slat & glue the batten to the tenons. The dovetailed tenons or pins would be able to move in the slot, while the batten is holding firm.

[Andrew Hughes]

The coopered boxes I’ve made that didn’t have floating panels eventually split on the top natural wood movement. It’s really not that big of a deal and far easier to make then a floating panel.
Ive used old growth VG fir and they still split.
I suspect the split widens and shrinks during the seasons. I don’t consider it a problem .

[Doug Dawson]

The coopered boxes I’ve made that didn’t have floating panels eventually split on the top natural wood movement. It’s really not that big of a deal and far easier to make then a floating panel.
Ive used old growth VG fir and they still split.
I suspect the split widens and shrinks during the seasons. I don’t consider it a problem .

Maybe that’s why barrels are shaped the way they are.

I say, cinch the top and fill it with whiskey! :^)

[Alex Zeller]

Is there any reason why the side boards and supports have to have the grain running opposite of the top? Normally you would do it for strength but If all the wood is running the same way it'll move very close to the same and can be glued. I would thin that it would be more than strong enough.

I could allow the ends to float. Just secure the center of the curve to the ends and supports. By my calculations if the top is about 20 front to back QSO would move about 3/8" front to back. If the center is secure that would be 3/16" on front. As long as the curve isn't too great I doubt there would be much more than a 1/16" of an inch up and down movement.

[Tom Bender]

How about T&G with the staves free to move?