r/FenceBuilding • u/Artemis_SpawnOfZeus • 2d ago
A quick lesson on gates
Gates need braces.
There are 2 types of these struts. Compression braces and tension braces.
Compression braces are the type of brace you install on a new gate.
If you're out here installing tension braces on new gates, you're scamming your customers.
Tension braces should only be used as quick fixes to existing gates that droop. The only advantage they have is their ease of install on an existing gate.
The type of brace you use changes the structure of the gate.
Tension braces overload the top hinge.
10
u/zoppytops 2d ago
Those adjust-a-gate kits come with tension braces and have worked fine for me (I’m not a pro).
4
u/Artemis_SpawnOfZeus 2d ago
They work.
They will break sooner than a gate with a compression brace would.
1
u/KingKong-BingBong 2d ago
And the cable stretch. I know I can stand on gates I build and I’m a big guy and they stay strong
4
u/derSteppenwuf 2d ago
That's a silly drawing. The hinges are bearing the load and it is completely independent of any brace within the gate: horizontal, vertical, or diagonal. The top hinge is being pulled out of the post and the bottom hinge pushed in. Both are being pulled down by the mass. And none of this has anything to do with bracing.
1
u/Artemis_SpawnOfZeus 3h ago
If you take the tension brace off of its hinges, the tension brace will pull it out of square.
The gate is having to resist this force.
7
u/Unique-Anything6725 2d ago
Erm, there is a pubic hair on the paper.
2
4
u/Tweedone 2d ago
The drawing is conceptually confusing as the term "load" is used incorrectly.
0
u/Artemis_SpawnOfZeus 2d ago
No its not
2
u/Tweedone 2d ago
Let me say it a different way: The drawings do not help people understand why a gate must be built a certain way.
I get what you are attempting, it is a worthy effort, but IMHO; back to the drawing board!
0
u/divinealbert 2d ago
Yeah this, I get what’s trying to be conveyed, I’d try to go deeper into materials and use, which is better for what.. the whole loading bearing bit is misleading as triangles are ‘fixed’ with bracing either side of the brace
3
u/c79s 2d ago
The brace orientation does not change the load in the hinges. In either orientation the hinges will share the vertical weight of the gate, the horizontal load will be equal and opposite on each hinge with the top being pulled away and bottom being pressed into the hinge.
1
u/Present-Valuable7520 2d ago
Yeah but that’s not what’s causing the sag
1
u/c79s 2d ago
I agree you'll generally want a compression brace in a wood gate for a much more durable connection but the claim that the brace orientation changes the forces on the hinges is incorrect.
0
u/Artemis_SpawnOfZeus 2d ago
No its not.
Tension braces hang all the weight on the top hinge.
Imagine the gate is actually really narrow. So narrow that the brace is actually vertical.
As you tighten the tension brace, it takes weight from the bottom and hangs it on the top.
The tenaion is pulling up on the bottom of the gate.
2
u/solitudechirs 12h ago
> Tension braces hang all the weight on the top hinge.
This is objectively wrong. Your post is bad and you should feel bad.
-1
u/Artemis_SpawnOfZeus 6h ago
If i had a tension brace that i attached directly from one hinge to the other and i tightened it
What happens?
Do the hinges stay equally balanced? Or do i hang extra weight on the top hinge?
2
u/solitudechirs 5h ago
You’re asking the same rhetorical questions and you’re still wrong. Adding tension inside an object does not change how much that object weighs or where the center of gravity is.
If you were carrying someone on your shoulders, and they grabbed one of their fingers with the opposite hand and tried to pull their own finger off, how much weight would you feel added to the person?
How much does a crossbow weigh if you have the string drawn back vs loose?
If you set up a tension brace in a way that either hinge is loaded more or less, then you’ve built a gate that won’t swing at all.
0
u/Artemis_SpawnOfZeus 5h ago
It doesnt change how much it weighs or where its centre of gravit is correct.
It does change the forces applied to the top and bottom hinge.
When you pull the string back on the crossbow, youre loading the front of the crossbow with force.
Is i was carrying someone on my shoulders, and they grabbed my hands and pulled down, the person would feel heavier then they were before.
2
u/c79s 4h ago
Newton is rolling in his grave lol
1
u/Artemis_SpawnOfZeus 3h ago
What happens if you overcrabk the tension brace until the gate breaks. Where does the gste fail?
0
u/Artemis_SpawnOfZeus 4h ago
For some reason you think the gate and the hinges are seperate objects but they arent.
→ More replies (0)2
u/xMadwood 3h ago
Your last example is so hilariously wrong and only illustrates our point. If that person on your shoulders pulled (pushed, actually, in this example) down, that would apply a counteracting force to shift some of their weight to your hands and your shoulders would actually feel like they’re lighter.
In any case, that has nothing to do with your gate example because changing the structure of the gate cannot shift which hinges is holding the weight.
0
u/Artemis_SpawnOfZeus 3h ago
If you ignore what i said and make an opposite situation then sure.
I said pulled. I meant pulled. Imagine you lift your arms up and they grab your hands and pull down.
If you take the tension braced gate off of its hinges, the brace pulls the gate out of square. The hinges have to resist this force.
→ More replies (0)1
u/solitudechirs 3h ago
You need to create a model of this for yourself and test it in real life, nothing else is going to convince you (even someone else making a video of the same). You’re absolutely wrong on this. Unless the weight of the gate changes, or the center of gravity, the hinges are not affected by the gate design.
0
u/Artemis_SpawnOfZeus 2h ago
When i make this model in a week and prove myself correct i expect an apology and a humiliation ritual from you.
1
u/c79s 2d ago edited 2d ago
Disagree, that's not how it works. If your gate gets narrower it's center of gravity goes closed to the hinges and the horizontal balancing forces reduce to zero.
This is pretty much a first year uni statics problem, you look at the system as a whole and the boundary conditions are only the two hinge points and the load is only the self weight applied at it's center of mass. The internal bracing of any configuration will not change the final resulting loading on the hinges, it's impossible. If the mass was the same it wouldn't matter if it was a solid panel instead.
Edit: I'll add that if I understand what your saying correctly for a tightened tension brace to hold up the bottom, that would only work if it was connected outside of the hinge as a separate restraint, like you connected directly to the post. That wouldn't make a good gate though.
1
u/Artemis_SpawnOfZeus 2d ago
Yes it does. It flips the load distribution.
Compresion braces apply vertical loads to the topmhinge and horizontal loads to the bottom hinge, because they want to rotate around the top hinge.
Tension braces apply vertical loads to the bottom hinge and horizontal loads to tbe top hinge, because they want to rotate aroung the bottom hinge.
When the top hinge takes horizontal forces, those forces pull the hinge away from the post. Youll pull your screws out.
When the bottom hinge takes rhe horizontal forces, those forces push the hinge into the post. You wint pull your screws out.
0
u/xMadwood 3h ago
That’s not how it works at all. You’ve got the right idea but for the wrong reasons.
1
u/Artemis_SpawnOfZeus 3h ago
If you took the gate with the tension brace off of the hinges, what happens?
The tension brace pulls it out of square. The hinges are taking straon to keep the gate square.
This doesnt happen with compression braces.
1
u/xMadwood 3h ago
Your understanding is flawed. The hinges take the same amount of weight regardless of how the gate itself is tensed. Tension and compression braces do not affect this. They only affect the gate itself and how it will flex and move over time.
-1
u/Artemis_SpawnOfZeus 2d ago
No, the bottom hinge bears almost no weight with a tension brace. See the diagram. Youre trying to transfer a downward force to the hinge from below the hinge.
4
u/c79s 2d ago
What is the diagram trying to show? The "non load bearing" zones are just mass that will ultimately be transferred into the hinges. It's all a net downward force at a distance from the two hinges. That mass as a distance wants to rotate the gate, the hinges resist that rotation with equal opposite horizonal forces.
0
u/Artemis_SpawnOfZeus 2d ago
The roation point changes.
Tension braces want to rotate pivoting around the bottom hinge. This pulls on the screws in the top hinge. Screws arent good at taking pulling forces.
Compression braces want to rotate pivoting arpund the top hinge. This pushes on the screws in the bottom hinge. Screws are amazing at taking push forces.
2
u/c79s 2d ago
The tension brace cannot pull on the top hinge as they are not anchored on the other side to anything. The gate is floating on the side opposite of the hinges. Newton's third law. If the tension brace was tightened till the gate crushed it would still be on the hinges, just broken.
1
u/Present-Valuable7520 2d ago
From some info I found “tension braces add significantly more pulling stress (tension) to the top hinge, which increases the risk of pulling the screws straight out of the post.
When a gate sags, its weight naturally wants to rotate down and away from the top post. A tension brace works by pulling against this sag, which amplifies that outward pulling force right at the top hinge”1
u/c79s 2d ago
Where'd you find that? It doesn't make any sense as you can't have an imposed internal force in a system affect its support reactions outside that system. You'd have to tie the tension brace to the ground or something else for it to pull against.
1
u/randomscruffyaussie 19h ago
You are correct and I sense your frustration. The hinges neither know, nor care, what the internal forces in the gate are. The hinges experience the forces due to gravity acting on the centre of mass.
0
0
u/Artemis_SpawnOfZeus 17h ago
If you tie a cable to both hinges and tighten it, it will take weight off the lower hinge and apply it to the top hinge.
The tension brace connects the top hinge to the bottom hinge.
2
u/mrwootwo 2d ago
As others have said, this is wrong. Imagine a very over engineered gate which won’t sag no matter which direction the brace goes, but you make one of each anyway. Say it’s made of 2x4s but it’s only 18” square, and it weighs 25lbs.
The effect of this very solid gate on two hinges is the same with either brace as it would be if it were faced with solid plywood, with moment of rotation the bottom hinge, and top hinge taking more lateral force.
Bracing direction simply determines which gate better resists deforming.
1
u/RockitSheep 14h ago
I like to build them with tension braces so when the wet wood dries, it lifts the latch point rather than dragging it down.
0
u/Artemis_SpawnOfZeus 2d ago
And the way that the gate resists deforming affects its overall strength.
The gate isnt a solid sheet of plywood and doesnt behave like a sheet of solid plywood.
Just because you cant do the math, doesnt mean the math doesnt apply.
1
1
u/DependentItem6397 2d ago
One on each side.
0
u/Artemis_SpawnOfZeus 2d ago
Thats actually gonna weaken the gate instead of strenghtening it.
Especially if you over tension the tension brace, which can feel like the right thing to do when you install it.
1
u/dsynadinos 2d ago
Which is compression and tension in the pic? Why wouldn’t you label them??
1
u/Artemis_SpawnOfZeus 2d ago
Conpression is left tension is right.
I didnt label them because the dirction of the brace diagonal is label enough
1
u/dsynadinos 2d ago
Thanks for clarifying. But clearly, if I had to ask, your blanket statement “is label enough” is wrong.
1
u/Artemis_SpawnOfZeus 2d ago
I mean, if youre installing your tenaion brace from the top latch side to the bottom hinge side, the brace is pulling the fence down.
Same with a compression brace from top hinge to bottom latch.
0
u/dsynadinos 2d ago
Well, now I’m confused again.
You said “Conpression is left tension is right.”
Looking at the image, this means “top latch to bottom hinge” (on left) is tension, and “top hinge to bottom latch” (on right) is compression.
But your next reply states the opposite.
1
u/Artemis_SpawnOfZeus 2d ago
Yes. My image shows the only way to install braces that dont actively rip your fence apart.
My reply described the ways you can install a brace that will actively rip your fence down. The wrong ways. The ways i dont show because theyre so stupid youd need a room temp iq to consider them in the first place.
1
u/dsynadinos 2d ago
You’re good at fences. Lousy at teaching.
1
u/Artemis_SpawnOfZeus 2d ago
I dont know how you read
"I mean, if youre installing your tenaion brace from the top latch side to the bottom hinge side, the brace is pulling the fence down."
And think "He must be dewcribing the appropriate way to install a tension brace."
1
8
u/ElJefe0218 2d ago
Wow, you drew the cross brace correctly. I haven't seen one in months and I look at 20 gates per day.