Making steel gates with box section

[iainel]

Hey guys

I am looking to make replacement side gates for my property as the wooden ones are old, drooping and falling apart. It consists of a standard size single personnel gate, and a large opening vehicle gate (will get exact measurements later but probably 2.5m or so?)

I was thinking of ripping them out and replacing the existing 2x4 wood posts (currently bolted to small concrete posts) with 4x4 posts for extra weight, then making the gates themselves out of steel box section.

What material sizes would be recommended for this? 40x40mm box section 2mm wall thickness is what I was thinking of but I've never done this kind of project before so not sure if that's sufficient.

I was planning to X brace it once I have the square shape then have strips of thinner metal with holes to bolt wooden cladding inside so it's not possible to see through it.

Something like this but just straight across the top:

Thoughts or ideas would be most welcome so I can start pricing up materials and how much effort it'll be.

Thanks!

 

[mart]

You mention replacing the existing 2x4 wood posts with 4x4. I am assuming that you don`t mean wood 4x4 posts for the new gates?

 

[iainel]

Heh I did actually figured they just needed to hold a hinge bracket? If metal what would I be looking to use for those then?

 

[Maker]

I don't know what size material but I would guess something like 3" x 3" x 1/8" steel box section. Just make sure to cap off the top and bottom and paint, galvanise or coat it in some way to stop it rusting, because that's just as bad as a wooden post.

 

[mart]

Personally it makes no sense to use wood posts again-wood rots eventually. I know steel needs painting etc, but with steel you have support strength. I would get rid of the concrete posts and start afresh with good sized steel box. Like 80mm/3inch. Undercoat/paint the bottom 3 feet, and concrete the posts 2 feet in.
The gates I made took 3 men to lift one on to the hinges when finished. Think about that sort of swinging weight. Below are some pics of my posts (80mm) from 4 years ago.

 

[Rig Pig]

Last set of gates I fitted I used 6" galv pipe for the posts, it came from a scrapyard for very little cash.

 

[steviec_lj]

Get the heaviest posts you can.

I've got two 8' gates, one at either end of the drive to keep the dogs and children in. I put 100x100x5mm box section posts in the ground, sunk 4' with around 6' out of the ground, and one gate is already dragging the post over 3mm at the top. They were put in 18 months ago perfectly square, straight and level with the gates hung.

So, as said, get some proper, heavy duty posts sunk in, in advance. Some proper hinges too, not like next door, who's mounted 'T' hinges so his gates drag the screws out of the posts.

 

[DAPPH]

For my home made 1200 tall gates (A 1000 mm side gate and a 1.8m gate ) in 16 ( ?) mm square bar with a transom and top scroll work on a 6 mm x 50 mm frame of flat bar , I used M/S post made from new 100 mm box with a 10 mm wall , some 2.2 mtr long ( Bloody heavy ) , put a cap on , drilled a drain/air hole just by the weld of the cap before putting on the caps.

Welded the hinge pins on the posts so they matched the gates , drilled the hinge pin on the house side of the gates so as to fit a blind knock in high tensile pin to help retain , stop gate theft , then sent the lot off for hot dip galvanizing . There were two big brass washers to be added between each hinge and the bottom of the hinge pin to try and save me from having to grease them more than once ( removed for the galvanizing exercise ).

When I got every thing back after three weeks of letting it weather in the galvanizers yard . The posts were painted with black bitumen & sat on an engineering brick at the bottom of the holes to stop them sinking any more in the clay so that they would just show a 25 mm black band above the level of troweled over concrete . Carefully and tidily dug the post holes a metre deep by 500 x 500 with my long handled spade (almost 6 foot long on a pitchfork handle )

Eased the gates over the pins & brass washers whilst the post was sat in the hole , popped in the security pins , then used four sets of double wedges knocked in from opposing sides to lift the gates to keep them level and allow me to set up some wooden propsso I could adjust the plane & keep them vertical and true .

I used a good old 6 to 1 mix of 3/4 down instead of quick set as I already had plenty of the materials to hand , Left it to set for ten days before moving the wedges and supports .

When I went back there 8 years ago to see my old neighbour friends , 5 years after putting the gates up the new owner of my old home told me that he has never seen such good gates as they are still fully lined up & haven't needed any painting .

The leverage on the gate post in foot pounds is quite amazing so do make the hole big enough to take about something like a 120% counter weight of concrete & steel frothe gate weight found above ground . Other wise the first wet weather will like as not see the weight of the gates pull them inwards making it difficult to adjust them to close well . The old saying for putting in a post for every one foot ( 303 mm ) above ground you need to have six inches ( 150 mm ) below ground is a good time tested maxim to follow , as well as having the right size counter balance below ground .

 

[Gritineye]

In clay ground it can be a good idea to weld in a buried spreader beam between the posts to keep them aligned over time, the gates can be trial fitted when flat on the ground.

 

[Maker]

In clay ground it can be a good idea to weld in a buried spreader beam between the posts to keep them aligned over time, the gates can be trial fitted when flat on the ground.

That's a good idea, put in some big diagonals and corner gussets as well, just to help keep the posts square.

 

[MrFluffy]

Why no love for decent poured concrete pillars? I have 3.5m wide steel gates so we can get heavy vehicles in to the yard still, but theyre mounted on poured concrete posts. I just stacked up a load of the fancy post blocks on top of a decent foundation and stuck rebar inside, a length of conduit to carry power to lights and gate openers and filled with slurm well rammed down. Now five years on I have to repaint and fettle the gates yet again and one of my actuators sticks in cold weather and requires a kick to remind it who's boss, but the "stone" pillars still look great. Gates havent moved at all either.

 

[steviec_lj]

Much love for poured concrete posts. They just have their place.

Unfortunately unless the opening is oversized, they're rarely used.

 

[iainel]

Great info thanks very much guys. Seems like it was a daft idea keeping the concrete posts so I'll rip it all up and start with some 100mm box section. Sounds like I was about right with 40mm box for the gate structures though.

It's a 3 metre opening so both gates will be 1.5 metres alongside a personnel gate of 1 metre. It's current one badly made wooden gate that's getting worse every time I open it!

Thanks guys.

 

[mart]

Depending on how far you have progressed, I may be coming back here a bit late to mention this.

If the width of your drive opening is exactly 3 meters for example, and you make the gates exactly 3 meters, you may incur a problem, if you don’t keep the following in mind. Between the gate post and the gate, there is inevitably a gap for the hinge. Depending on the hinge type used the hinges are adjustable, which personally I found to be of great help. I tried to measure (and make) my gates so that I had adjustment in both ways-towards the post(s) and away from the posts. In any event, you will only get a few inches either way out of the adjustments, so do think it through carefully.

Measure the gap between your posts carefully, between the tops and between the bottoms (even though you are hoping for them to be set squarely). I allowed for about a 50mm gap on the hinge sides (so you can see that this means the total width of the gates need to be reduced by 100mm in this example). It is easy to overlook things like this if you have never done it previously, and good luck!

 

[DAPPH]

If you put welded hinge hangers/brackets on the front or back of the square post to the outer edge rather than on the side facing across the gap, you can have it so the gate is opens only one way and that when opened it actually sits back from the edge of the gate posts & runs flat to the wall /fence.