A door is to be constructed thus (fixed width font needed):
+-----+ |\ | h | \ | i | \ | n | \ | g | \| e +-----+ sor thus:
+-----+ h |\ | i | \ | n | \ | g | \ | e | \| s +-----+Which is right? (And why does it matter?)
In the first, the diagonal is in compression. In the second, it is in tension. Both can be made to work, but compression makes for simpler construction: It will work even if the brace is not jointed into the outer frame.
Colin Bignell
Depends whether the diagonal strut and its fixing are designed to work in tension or compression. The top option works with a piece of wood, which is reasonable in compression and easier to fix that way. If you were using a steel rod which would work better in tension then the lower option would be the way to go.
The first one (assuming traditional ledge frame and braced construction, where the brace works best in compression. On a welded steel frame for example it would not make much difference).
The above answers are correct. Unless you want to use a bit of steel wire for the diagonal, in which case, the second one would be correct (tension).
Our garden gate was fitted with the strut in tension. I've had to add a wire to stop it sagging. (wasn't convenient to rehang)
Andy
Also, where should the hinges be? I mean should the top one be (say)
1/4 of the way down from the top of the door and the bottom one 1/4 of the way up from the bottom, or some other fraction? The door is for a shed and will be constructed from shiplap on (the metric equivalent of) a 2" x 2" timber frame.
If its a ledged and braced door, then usually the Tee hinges are placed on the horizontal ledges top and bottom.
If using normal hinges on a door, the traditional spacings are 6" down from the top, 8" up from the bottom, and another midway between them. A modern version is sometimes 6" up rather than 8", and on light weight doors the middle one left off.
And sometimes the third hinge is noticeably higher than the middle.
Common in hospitals for some reason...
Probably because hospital doors are fire retardant, hence much heavier than "normal" ones.
I would have expected the optimum position to very, very close to the same on all doors. Is it that on heavier doors it is worth going out of your way to identify that optimum point and fix accordingly? Whereas on lighter doors simply measure the middle?
And agreed about hospital doors. That was precisely where I have most often noticed them.
There can be a lot of outward force at the top of a heavy door, hence two hinges to hold it better.
Mentally remove the door & just look at the brace. In the top example it's a gallows bracket.
Centre hinge in the middle is the norm on external doors but it's mainly there to stop the door warping.
If it is *really* like this it doesn't matter.
Forget the outer "upright" and think of the triange formed by the hinge, brace, and third horizontal. In the first case, the brace is in compression, in the second it is in tension. For lifting equipment, say if you wanted to suspend a pulley away from a wall, you generally find the second case because the "brace" is in tension so it can't buckle, and less material is required.
For proper ledge and brace, with the brace fitted into a small cutaway in the ledge, the top one is better. This is because in that case the brace is in compression, and any movement in the structure tends to lock the brace and the ledge together.
Buckling isn't an issue for realistic geometries of door brace, and in any case it is stabilised by being screwed or nailed to the main woodwork.
When I wanted 3 hinges for my new shed I decided on stainless steel normal hinges. SF and TS did them in pairs but Wickes had packs of 3. I don't know if that's still the case, but was cheaper than buying 2 packs - and 1 hinge is a bit like 1 sock or glove.
Indeed.
On the hospital ones, it may be a reflection of the fact they are expected to be repeatedly "hit" below centre with the end of a bed - perhaps putting more torsion on the top hinges?
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