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The right hinge for the job

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Forum topic by gavinzagreb posted 03-13-2013 07:33 PM 3529 views 0 times favorited 12 replies Add to Favorites Watch
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gavinzagreb

210 posts in 1787 days


03-13-2013 07:33 PM

Topic tags/keywords: hinge question

A friend has asked me to design and make a table that folds down from the wall for him.
Despite the fact I have a fair amount of woodworking experience, I haven’t done much work with hinges.

The legs need to hold flat to the underside of the tabletop, and fold out to 90 degrees.
Both the end of the tabletop and the legs are cut at 45 degrees.
You can see in this pic where the pivot point needs to be. (the red dot)

Which hinge and which installation method is best for this task.

Thanks for any assistance.

Gav


12 replies so far

View CharlieM1958's profile

CharlieM1958

16244 posts in 3686 days


#1 posted 03-13-2013 08:02 PM

I’d probably go to a piano hinge in that situation. Whatever hinge you use, you’ll have to mortise it so that the legs will fold 100% flat.

-- Charlie M. "Woodworking - patience = firewood"

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Loren

8315 posts in 3116 days


#2 posted 03-13-2013 09:28 PM

Those miter corners won’t hold up.

Flush mount card table hinges would work. If you
can find a way to make them work, quadrant
hinges have a positive 90 degree stop.

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gavinzagreb

210 posts in 1787 days


#3 posted 03-13-2013 10:29 PM

Thanks guys-
I had thought maybe a piano hinge, might have to try on some scrap to see if it will work.
I’ll look into the card table hinges and quadrant hinges but not sure I’ll find them here.

Can you explain this more. ‘Those miter corners won’t hold up.’
You mean they will receive wear and tear and break ?
When the table is in the down position, the mitres are closed to form 90 degree corner, and when it’s in the up position, nothing touches them.
I’m not sure what you mean.

View cabmaker's profile

cabmaker

1507 posts in 2277 days


#4 posted 03-13-2013 10:32 PM

Continuious hinge would work fine mortised as stated and a quirk mitre may be in order to eliminate long point damage.

View CharlieM1958's profile

CharlieM1958

16244 posts in 3686 days


#5 posted 03-13-2013 11:55 PM

I think what Loren is talking about is that every time you unfold the legs you will be, in effect, jamming the points of those two miters into each other. Over time, there will be compression and possible breakage of the wood, and the joint will become loose and ill-fitting. It might not be too big of an issue if the table is unfolded gently and sparingly, but everyday use will take a toll pretty quickly.

-- Charlie M. "Woodworking - patience = firewood"

View MNgary's profile

MNgary

296 posts in 1885 days


#6 posted 03-14-2013 12:18 AM

I must not be understanding your drawing because the pivot point I see won’t allow the leg to rest flat against the top’s underside.

-- I dream of the world where a duck can cross the road and no one asks why.

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gavinzagreb

210 posts in 1787 days


#7 posted 03-14-2013 08:42 AM

Charlie, thanks for clearing up the mitre wear issue. Perhaps slightly rounding over that point would help or more the quirk mitre (new term for me) as cabmaker suggested. I wasn’t going to rely on the mitre to stop the legs either, I had thought to use some kind of hardware for locking the legs at 90 degrees.

MNgary, I modelled it in sketchup and it shows that it will fold flat using that pivot point, as you can see in the pic below.

Do you mean the piano hinge will stop it from folding flat if mounted at that pivot point ?
Definitely will have to experiment a little to understand the physics of it.
I guess if it’s 2-3mm from flat at the pivot point, it won’t matter too much.

Looked into the card table hinges and they look ideal for mounting on the edge, but I’d have to lose the mitre, and I can’t find a local supllier.

Thanks everyone.

Gav

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gavinzagreb

210 posts in 1787 days


#8 posted 03-14-2013 05:00 PM

I made a quick test in some scrap with a standard butt hinge and despite my rough mortising, it works.
I imagine a piano hinge would work even better.
Seems you just need to mortise deep enough so the pivot point of the hinge is low enough.

View CharlieM1958's profile

CharlieM1958

16244 posts in 3686 days


#9 posted 03-14-2013 05:16 PM

I believe you’ve got the right general idea now.

-- Charlie M. "Woodworking - patience = firewood"

View MrRon's profile

MrRon

3927 posts in 2711 days


#10 posted 03-14-2013 05:59 PM

This is how I would do it.

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gavinzagreb

210 posts in 1787 days


#11 posted 03-14-2013 07:53 PM

Certainly it could be done easier that way MrRon, but I always end up challenging myself.

I want it to look like a picture frame when it’s folded up onto the wall. Actually my friend wants it like that.

I haven’t even got around to thinking of what kind of catch to use on the wall. It’s also going to be 150 cm x 70cm so will be quite heavy. He can use it as a workout machine too.

View MNgary's profile

MNgary

296 posts in 1885 days


#12 posted 03-14-2013 08:15 PM

I stand corrected. When I first viewed the sketch I didn’t see it as three dimensional. My brain saw a 2D drawing with the leg having a slot and the hinge was one-fourth the way back from the front.

-- I dream of the world where a duck can cross the road and no one asks why.

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