piano hinge on solid wood panels.. movement concerns?

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piano hinge on solid wood panels.. movement concerns? - mound - 01-14-2019

Hi - I'm planning a collapsable sewing machine cabinet for LOML.. Wanted to use solid wood. Any concerns about joining two large solid oak panels (3/4", 30"L x 24" W) with a piano hinge? (Hinged along the 24" long end-grain ends, both panels having the same grain orientation?) The panels would expand and shrink the same as each other under ordinary, but would having that piano hinge connecting them prevent movement and lead to damage?

thanks!

RE: piano hinge on solid wood panels.. movement concerns? - jasfrank - 01-14-2019

Wood moves very little along its length so you’re good to go

RE: piano hinge on solid wood panels.. movement concerns? - DaveR1 - 01-14-2019

(01-14-2019, 08:10 AM)mound Wrote: Hinged along the 24" long end-grain ends, both panels having the same grain orientation.

Hmmm.... Good question. How are the boards for the panels cut? Quartersawn? Are the panels cut from the same board? (Continuous grain across the hinge line?)

I think there'd be enough slop in the screw holes so that it wouldn't be a huge problem but if you are concerned, you might exchange the continuous hinge for three butt hinges spread across the joint.

RE: piano hinge on solid wood panels.. movement concerns? - mound - 01-14-2019

(01-14-2019, 08:40 AM)DaveR1 Wrote: Hmmm.... Good question. How are the boards for the panels cut? Quartersawn? Are the panels cut from the same board? (Continuous grain across the hinge line?)

I think there'd be enough slop in the screw holes so that it wouldn't be a huge problem but if you are concerned, you might exchange the continuous hinge for three butt hinges spread across the joint.

To clarify (for jasfrank's reply) the hinge would run side to side along the end-grain - in the same direction the wood moves.

How the boards are cut is still TBD.. I may go quartersawn for the look, in which case I think there would be no issue.. But if not, it would still likely be continuous grain across the hinge line, but the panels, being 24" would be glue-ups of course, but all from the same stock.

RE: piano hinge on solid wood panels.. movement concerns? - jteneyck - 01-14-2019

That's going to be a problem. Three smaller butt hinges aren't going to be much better because the end ones still don't allow the wood to move. A better solution would be to use frame and panel construction so the solid wood panel can float in the frame, and mount the hinge to the frame. Make the panel the same thickness as the frame so everything is flat and smooth.

John

RE: piano hinge on solid wood panels.. movement concerns? - MichaelMouse - 01-14-2019

(01-14-2019, 08:47 AM)mound Wrote: To clarify (for jasfrank's reply) the hinge would run side to side along the end-grain - in the same direction the wood moves.

How the boards are cut is still TBD.. I may go quartersawn for the look, in which case I think there would be no issue.. But if not, it would still likely be continuous grain across the hinge line, but the panels, being 24" would be glue-ups of course, but all from the same stock.

Have to remind ourselves periodically that wood has to have something to hang onto in order to move. Distance between fasteners is what, two inches? Means a MAXIMUM movement and therefore stress is computed between fasteners. ~1/64th perhaps, if you're talking worst case and NOT finishing both sides to limit the rate of moisture uptake and loss with RH changes.

If your design demands no frame/panel, I would not be afraid to do it as you suggest.

RE: piano hinge on solid wood panels.. movement concerns? - DaveR1 - 01-14-2019

(01-14-2019, 09:41 AM)jteneyck Wrote: Three smaller butt hinges aren't going to be much better because the end ones still don't allow the wood to move.

How? The butt hinges would be no more than 1-1/2 or 2 in. wide with maybe 1-3/4 between screws. The wood isn't going to move that much between those screws and the hinges won't be connected to each other so the panels can expand and contract as they want without any problem.

RE: piano hinge on solid wood panels.. movement concerns? - jteneyck - 01-14-2019

(01-14-2019, 10:12 AM)DaveR1 Wrote: How? The butt hinges would be no more than 1-1/2 or 2 in. wide with maybe 1-3/4 between screws. The wood isn't going to move that much between those screws and the hinges won't be connected to each other so the panels can expand and contract as they want without any problem.

Of course you are right. I must have had my head on backwards when I wrote that. Sorry for any confusion I caused.

John

RE: piano hinge on solid wood panels.. movement concerns? - DaveR1 - 01-14-2019

(01-14-2019, 10:47 AM)jteneyck Wrote: Of course you are right. I must have had my head on backwards when I wrote that. Sorry for any confusion I caused.

John

No worries. Now, you would have been correct if there'd been a cross grain situation.
Wink

RE: piano hinge on solid wood panels.. movement concerns? - Phil Thien - 01-14-2019

My concern would be that the two pieces of wood won't expand/contract in sync (even if cut from one continuous piece).

I'd still find another way to do it.