- Thread starter Turbo
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On wood doors yes to keep the joints in compression.
So the pressure is on the face not the fixing nail, pin, dowel.
rtbcomp
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High at the hinge keeps the joints in compression - post #13 ???
Richard.
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6 and 2 3’s and out of steel it really isn’t going to make any difference whatsoever. I’d personally brace them at high side to latch. I like the real strength to be at the top furthest corner
If I build a gate and some twit swings on it the only thing likely to fail will be what ever some plonker has bolted it to. Use a substantial wall tube, weld them properly brace them how you like and assume they will get climbed on.
If I build a gate and some twit swings on it the only thing likely to fail will be what ever some plonker has bolted it to. Use a substantial wall tube, weld them properly brace them how you like and assume they will get climbed on.
No if it's high on the hinge end the brace is under tension not compression
Richard.
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In what instance are we talking about ?
The brace can be under both tension and compression in either direction. It depends where the force is applied to the gate.
A free swinging gate the brace is suffering from very little of either as the general rectangular shape would quite happily support itself without it.
Swing on it right at the furthest point and the brace going from lower hinge to high latch will be under compression
Same case scenario but The brace going the other way isn’t doing much at all a bit of tension.
Move the idiot further down the gate towards the hinges and things start to move in the opposite direction.
It also depends on where on the gate (height wise) the idiot stands or sits.
When I was a gate swinging idiot in my younger days we’d sit right on the top bar and do it properly.
However the half a job idiots that stood on the bottom bar change the rules again putting a lot more tension on a brace going low on the latch side.
The brace can be under both tension and compression in either direction. It depends where the force is applied to the gate.
A free swinging gate the brace is suffering from very little of either as the general rectangular shape would quite happily support itself without it.
Swing on it right at the furthest point and the brace going from lower hinge to high latch will be under compression
Same case scenario but The brace going the other way isn’t doing much at all a bit of tension.
Move the idiot further down the gate towards the hinges and things start to move in the opposite direction.
It also depends on where on the gate (height wise) the idiot stands or sits.
When I was a gate swinging idiot in my younger days we’d sit right on the top bar and do it properly.
However the half a job idiots that stood on the bottom bar change the rules again putting a lot more tension on a brace going low on the latch side.
Yikes, it seems I've started a good discussion! 
Thanks for all your replies & advice.
I'll not answer every post but I'll try to answer most of you, apologies if I miss you out.
To start with, nobody is going to be swinging on this gate, it will be sheeted with 6' box profile. It has to withstand an occasional strong wind, the last gate was wrecked when the latch came loose during a storm!
The ground underneath is very uneven, I had thought of a nose wheel!
The hanging post is a 6'x6' I beam set in concrete so not much fear of it bending.
I too would brace a wooden door low hinge to top latch, didn't know if steel was different.
I read all your posts, went out & had a look at the frame & did some more thinking. I'm liking the idea of 2 parallel diagonals to minimise heat distortion at the centre joint. Probably go \|\ as it will strengthen the bottom corner on the latch side. There will be a 20mm dia bar on that corner sliding down into a pipe set in the ground to keep the gate in place so it will be under some strain. Then there is a smaller 42" pedestrian gate that latches into the big gate.
Thanks for all your replies & advice.
I'll not answer every post but I'll try to answer most of you, apologies if I miss you out.To start with, nobody is going to be swinging on this gate, it will be sheeted with 6' box profile. It has to withstand an occasional strong wind, the last gate was wrecked when the latch came loose during a storm!
The ground underneath is very uneven, I had thought of a nose wheel!
The hanging post is a 6'x6' I beam set in concrete so not much fear of it bending.
I too would brace a wooden door low hinge to top latch, didn't know if steel was different.
I read all your posts, went out & had a look at the frame & did some more thinking. I'm liking the idea of 2 parallel diagonals to minimise heat distortion at the centre joint. Probably go \|\ as it will strengthen the bottom corner on the latch side. There will be a 20mm dia bar on that corner sliding down into a pipe set in the ground to keep the gate in place so it will be under some strain. Then there is a smaller 42" pedestrian gate that latches into the big gate.
rtbcomp
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Yes, but what I'm saying is that if the brace is high on the hinge side the vertical boards are being pushed against each other, thus making the door stronger.
Kent
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I have seen a bull destroy a steel field gate like it wasn't even there. I brace my estate gates both ways
Wood and you must be compresing not trying to tear the joint apart so bottom at hinge top at connection. You can go both ways if your coach bolting (mine are)
Wood and you must be compresing not trying to tear the joint apart so bottom at hinge top at connection. You can go both ways if your coach bolting (mine are)
rtbcomp
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The force on the boards is downwards, under their own weight.
Low at the hinge (b) the brace will try to become horizontal, thus tending to force the boards apart.
High at the hinge (a) the brace will try to become vertical, forcing the boards together (in compression)
Kent
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B is the stronger way with wood. Or steel.
B is the stonger. If you look at a fully boarded gate they are done with a midrail and the bottom brace is into the hinge up to the latch. The top section is likewise and the braces are v cut to nessle firmly into the corners of the E framing
https://www.google.co.uk/search?q=g...LfiAhXEVBUIHXOsCXIQ_AUIDygC&biw=1920&bih=1086
good thread... just from that google search it looks like most things work! but also noticed a few of the designs with the brace higher on the hinge end extend higher than the top rail, I dunno if that's mostly for for aesthetics or strength?
also didn't see any diagonal braces on gates with radius corners (like OP's), all mhorizontals/verticals/mesh....again I dunno how much that matters but must be stronger than a welded/mitred corner?
good thread... just from that google search it looks like most things work! but also noticed a few of the designs with the brace higher on the hinge end extend higher than the top rail, I dunno if that's mostly for for aesthetics or strength?
also didn't see any diagonal braces on gates with radius corners (like OP's), all mhorizontals/verticals/mesh....again I dunno how much that matters but must be stronger than a welded/mitred corner?
It makes no difference whatsoever which way the bracing is placed, hinge high/hinge low, when considering forces in frames. The resultant horizontal and vertical forces, opposing/cancelling the force within the bracing member, be it in tension or compression, are the same in each case. All that changes is which horizontal members end up in compression, the top or bottom tube for instance. The tension, or compression force, in that top/bottom tube will be the same in each case, as the weight of the gate is constant. For a member/brace in tension (hinge high) it matters only that the ends are securely welded. If the brace is sufficiently robust in section size, or welded at regular intervals to other internal frame members, to resist compression flexing/buckling, then it wouldn't matter if it were in compression (hinge low).
For timber, one uses hinge low for the combination of reasons previously mentioned by others, i.e, thicker/stiffer section size of timber brace (provides sufficient compression buckling resistance) and placing joint in compression to keep the joint tight, supported in good door construction by the use of gunstock joints to better resist compression movement at joint. So for metal gates, it's really down to personal preference, as long as if placed in compression the brace can't 'collapse'/flex sideways. Sorry if that was long winded.
For timber, one uses hinge low for the combination of reasons previously mentioned by others, i.e, thicker/stiffer section size of timber brace (provides sufficient compression buckling resistance) and placing joint in compression to keep the joint tight, supported in good door construction by the use of gunstock joints to better resist compression movement at joint. So for metal gates, it's really down to personal preference, as long as if placed in compression the brace can't 'collapse'/flex sideways. Sorry if that was long winded.
Gareth J
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Bearing in mind steel is much stronger in tension than compression, and that attaching it with weld should make the joints as strong or stronger than the parent, how come you think it's stronger to use steel in compression here?
As you pointed out, with wood, it's better to put it in compression and set it in with notches, or whatever, so that the joints aren't torn apart (in tension)
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Catch side top to lower hinge side.
That way any forces transferred through the frame are passed to the hinge and post in a manner that pushes it toward the post, rather than a pulling motion acting on the top hinge which could end up ripping the hinge out.
In reality, most steel gates are fairly substantialy made so it's not going to make much difference.
Always try and fit at least one adjustable hinge too, so any slight sag can be adjusted for at installation.
That way any forces transferred through the frame are passed to the hinge and post in a manner that pushes it toward the post, rather than a pulling motion acting on the top hinge which could end up ripping the hinge out.
In reality, most steel gates are fairly substantialy made so it's not going to make much difference.
Always try and fit at least one adjustable hinge too, so any slight sag can be adjusted for at installation.
rtbcomp
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Personally as far as forces on the hinge are concerned I don't see any difference between these:
C is a solid sheet and the rest are welded up from tube or whatever.
In every case the weight of the gate is acting downwards through the centre and the forces on the hinges and post are the same in all cases.
F will tend to distort from a rectangle to a rhombus, D & E will be stronger and as strong as each other due to the diagonal brace forming two triangles.
C is a solid sheet and the rest are welded up from tube or whatever.
In every case the weight of the gate is acting downwards through the centre and the forces on the hinges and post are the same in all cases.
F will tend to distort from a rectangle to a rhombus, D & E will be stronger and as strong as each other due to the diagonal brace forming two triangles.
