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6:44 pm
NWBA Member
September 29, 2011
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Finally getting around to building a driveway gate. Two halves, opens from the middle, about 7.5 ft. each half, average 1.5 x .25 inch stock, so fairly heavy, riveted primarily, attached to 2 large granite boulders, top hinge attached to rock, bottom hinge in ground, maybe drilled block with ball bearing, pin riding on bearing.
The thing is, I know there must be a bunch I'm not taking into consideration. First time around there always is, so the ideal help would be a picture of the structural parts of gates with a discussion of structural strategies/tips and of hinge strategies in particular. Maybe there is a link or a book that would help me do the thing without having to take it apart next year to make it right. Or some of you who have this kind of experience could chime in. Thanks for your help.
7:09 pm
January 18, 2011
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This one is a biggie..........Copied from Francis Whitaker's "The Blacksmiths Cook Book".....A sketch of what you are trying to accomplish would help.
"Be who you are and say what you feel, because those who mind don't matter, and those who matter don't mind."
— Dr. Seuss
1:02 am
NWBA Member
September 29, 2011
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Ken Albert;12359 wrote:
Finally getting around to building a driveway gate. Two halves, opens from the middle, about 7.5 ft. each half, average 1.5 x .25 inch stock, so fairly heavy, riveted primarily, attached to 2 large granite boulders, top hinge attached to rock, bottom hinge in ground, maybe drilled block with ball bearing, pin riding on bearing.
The thing is, I know there must be a bunch I'm not taking into consideration. First time around there always is, so the ideal help would be a picture of the structural parts of gates with a discussion of structural strategies/tips and of hinge strategies in particular. Maybe there is a link or a book that would help me do the thing without having to take it apart next year to make it right. Or some of you who have this kind of experience could chime in. Thanks for your help.
I respect few people more than Groucho. Thank you, Bruce for your help. The gate will be 3.5 feet high with primarily a grid design, so few major triangle elements to hold the square. I plan to weld strategically to help retain shape without making too fabbed a look. There will be a flat stock member across the top to make it basically like an angle iron component with the same treatment vertically where the two gate panels come together. The outside verticals, where the hinge attaches will be something like 1.5 inch round stock drawn smaller for most of its length, maybe .75 x 1.5 square and upset a little larger before it forms the pin to enter the bottom block/hinge. With a skeleton footing at the base of both rocks and a sufficiently skookum upper hinge, I'm thinking the sag might not be too bad. It might be good to have some kind of adjustable feature in the top or bottom hinge, but I'm not sure what kind of design that would be. To remove much torque might be more than is reasonable for a 3.5 x 7.5 foot grid.
1:14 am
March 21, 2011
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Ken Albert;12359 wrote: ..... bottom hinge in ground....
Where is the installation? If it's here in the Great NorthWet then you might be concerned with water pooling in the bottom hinge and rusting it out.
To remove future sag you might consider mounting the top hinge over a shim plate that could be removed or replaced with a thinner plate in the future.
2:56 am
May 13, 2010
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The book "Forged Architectural Metalwork" by Peter Parkinson has a chapter on gates. It has lots of good information on gate design as well as lots of pictures of gates showing how other smiths solved the stiffening up of gates.
12:51 pm
January 18, 2011
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Sounds like they'll be pretty stout.......just don't factor out the sag factor, 7.5 ft of overhang can't be denied. I'd build in an adjustment on the posts at least.
"Be who you are and say what you feel, because those who mind don't matter, and those who matter don't mind."
— Dr. Seuss
3:31 pm
NWBA Member
September 29, 2011
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Thanks to you all for the input. I live in Olympia, so rust is always a problem. For the bottom hinge I was looking at a block hinge that has a zirk fitting. It would not actually be in the ground, rather embedded in concrete. Of course, water would be impossible to keep out, if it were kept greased, it should survive a while. I guess the alternative would be putting the pin in the concrete and the socket and bearing in the gate member.
I will look at the Parkinson information, English smith I think? There has to be significant sag over that length, can't get around it. The shim is a good solution I had been considering, but the thing I'm still puzzling is the details of that upper hinge attachment. The only thing ocurring to me is a wedge/expanding bolt that is not bottomed out at initial installation and can be driven further to take up sag. I guess it wouldn't have to drive far to take up a lot of sag over 7.5 feet.
Maybe an improvement would be to pin a weld plate solidly with epoxy over a shim, replace with thnner shim and shim under the bolt head to take up slack. A threaded rod through the weld plate would make dialing in the adjustment easier, but a person might notice that he could spin a couple of nuts and walk away with a new gate.
3:52 pm
January 18, 2011
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Ken Albert;12382 wrote: a person might notice that he could spin a couple of nuts and walk away with a new gate.
Don't be messin' with Sasquatch!!!...You can always make another.
"Be who you are and say what you feel, because those who mind don't matter, and those who matter don't mind."
— Dr. Seuss
4:34 pm
March 21, 2011
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Ken Albert;12382 wrote: I guess the alternative would be putting the pin in the concrete and the socket and bearing in the gate member.
Good idea.
6:27 pm
August 16, 2010
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If you are considering welding at strategic points, then sag should not be a problem.
The1/8" per foot allowance was used for traditionally made heel bars and tenons rivetted together, these would 'sag/settle' after installation
The stock sizes you are anticipating using are not comparable with the sizes of and weight of the traditional gates, typically, 2"+ square back stile, infill bars of 3/4" square, Dogbars 1/2" square, scrollwork 1/2" x 3/4", cross members 2 1/4" wide x 1/2 thick, Slam bars, inner stiles of similar proportions gates weighing over a ton each being a common size, Gates 6 feet plus high, hardly comparable with the modern concept of contemporary gates.
As to hanging the gates, It was common practice to extend the upper journals mounting to be extended and incorporated into the pillars and walls built at each side of the driveway.
It is essential that the supporting structures are solid enough not to move as the gates are operated, I have seen pillars crack and lean at the base as supporting walls have been rebuilt and the old extended internal strappings for the top journals removed.
The Hanging arrangement was a journal on the back stile towards the top of the stile, and at the base the back stile was forged round between swages and the end forge semi spherical to give a ball ended pin (Probably 1.5" diameter on a 2" square backstile) that then located into a cast/forged iron block that can be secured into the foundations that has a suitable clearance hole (1/16"+ on diameter) for the base of the back stile to fit into. The top of this block being above ground level the socket being well greased at installation.
These will stand and work for many years before any adjustment should be needed, it was common practice to set the gates so the centre opening was not parallel, a narrower gap at the base than the gap at the top, this discrepency was disguised by the slam bar, and allowed for a certain amount of wear on the top journals over the years.
If the gates are used regularly, there should not be too much of a problem with water ingress and rusting, sand and grit are more of a problem.
I hope thai has een of some use, and if you have any specific problems with it, please feel free to ask for clarification.
Good luck and success in the project.
6:56 pm
NWBA Member
September 29, 2011
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Wow, as a new member to this forum I had no idea it was so widely read. I need to school myself on the vocabulary you use, John. I'm sure my understanding of it is imprecise, but it puts a wonderful picture in my mind and gets me a good way down the road. Thanks very much for your information.
7:46 pm
January 18, 2011
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John Bellamy;12387 wrote: If you are considering welding at strategic points, then sag should not be a problem.
Welding mitigates sag but does not eliminate it. Size,shape eg a gate with an arch in the middle which puts more mass in the center...Adjustments are far easier if they're built in.....Just 1/16 rise in the leaf of a gate over 7.5ft is only 1/2'' of lift, I say it makes a difference....:)
"Be who you are and say what you feel, because those who mind don't matter, and those who matter don't mind."
— Dr. Seuss
1:28 pm
August 16, 2010
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Bruce Macmillan;12389 wrote: If you are considering welding at strategic points, then sag should not be a problem.
Welding mitigates sag but does not eliminate it. Size,shape eg a gate with an arch in the middle which puts more mass in the center...Adjustments are far easier if they're built in.....Just 1/16 rise in the leaf of a gate over 7.5ft is only 1/2'' of lift, I say it makes a difference....:)
In general I agree with your comment, however I was trying to constructively respond to the initial question and comments about sag bearing in mind this gate is by implication from materials to be used and sizes referred to, only relatively light being 3.5ft high by 7.5ft wide and so weight should not be an issue, the rise of the leaf can be easily acommodated at the initial installation.
From a practical point on gates this size (less than a standard farm fireld gate) if you want adjustment, pintles and screw eyes would do the job, but that is not what is specified in the initial post.
The Francis Whitaker reference is not relevant in this situation. An isolated piece of information that was based on practices at the time or previous to it being written. Still valid for that type of construction, heavily reliant on triangulation and the use of heel bars and other bracing methods to give rigidity and stability, unlike a welded joint that if done correctly is a unified solid joint unlikely to settle as would the more mechanical type of joints be suscebtible to.
That rule of thumb was used for large heavy drive gates similar in construction to this style of ironwork at Hampton Court Palace.although these are only screens but the material sizes and designs are consistent with the gates produced in that era.
I may be wrong here but I think part of this problem is lack of experience on making and hanging this size of structure by the gentleman posing the question, and he is to be applauded for researching and seeking different opinions, and the resulting responses should also help him and others more shy of asking.
The anatomy of a gate and the methods used to produce gates have changed vastly over this last century, and the reasons for doing/using certain methods have evolved and changed, this is progress and it is good, however it is also reasonable to bear in mind what, where, when and why any technique was /is used, the best application for the situation can then be utilised.
I hope this clarifies and to some extent justify my post, I did think it relevant and do not want to be contentious. It will be interesting to see pictures and comments from the maker when the installation is completed.
4:35 pm
January 18, 2011
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In general I agree with you John, the Whitacker reference was a bit of a stretch in this application but correct in a more general sense. All gates sag whether it's fractional or in whole numbers.
Driveway gates and garden are kinda like the difference between a knife an a sword. The rules change allot.
The small Benson gate I didn't factor in any lift or adjustment, what could go wrong there with 20'' leaves........
The branch gate was welded from hell to breakfast and the sag factor was minimal. The big mistake I made here is I got the gates hanging true and welded the hinges to the posts. That worked fine for a while then things settled in and I had to return, cut the welds, shim, re weld.....Good to go right?....Then it got hit by a garbage truck, same thing, return, cut, maybe some shims.....Point is if I'd bolted the hinges to the post, I could have done adjustments and repairs easily.......A better strategy I think.
For the later Kravis gate I used the 1/8 to the ft rule AND bolted on the hinge pin to the outer gate post. Which means it will NEVER be hit by a garbage truck...:smug:
"Be who you are and say what you feel, because those who mind don't matter, and those who matter don't mind."
— Dr. Seuss
9:53 pm
March 18, 2010
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Well, I think there are three things involved here (four, if you count garbage trucks). There's "lean" from loading on the hinge post. Then there's sag, which is just the elasticity and joints in the gate itself. And then there's settling in.
Best practice has a beam buried under the gate to support the posts.
“There are painters who transform the sun into a yellow spot,
but then there are others who, with the help of their art and their intelligence,
transform a yellow spot into the sun.” ~ Pablo Picasso ~
12:22 am
January 18, 2011
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Grant;12403 wrote: Well, I think there are three things involved here (four, if you count garbage trucks). There's "lean" from loading on the hinge post. Then there's sag, which is just the elasticity and joints in the gate itself. And then there's settling in.
Best practice has a beam buried under the gate to support the posts.
If you're saying there should be a vertical I beam or a beefy pipe, tube or some such sunk in the ground with lotsa crete for a post or an armature I agree, If not I don't understand you're last sentence. I don't know how many times clients have proudly displayed they're newly constructed columns of stone and say, "we want the gate(s) put here on the columns". I first look for some hint of some steel for the connection and drop the bomb.....''Do the columns have an armature?"....."A what?" "You know, a beam or something to actually support the weight of the gate", and then the fun begins...
The Kravis gate had an armature which left only the sag more or less. The biggie here was they're were no welds holding it together so if it sagged 1/8''per ft over 7' and I didn't allow for it they would have to be completely torn apart and re done. The ensuing rage probly would have led to the hiring of a new helper after he fled.........
Sorry, I'm not trying to bore you guys who already know this stuff, for those who don't; a nice job can turn into a nightmare on account of a seemingly insignificant detail. It can be a real bitch.
"Be who you are and say what you feel, because those who mind don't matter, and those who matter don't mind."
— Dr. Seuss
12:31 am
March 18, 2010
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No, I'm talking about a beam (not post) buried across the drive, so the posts and the beam form a "U".
“There are painters who transform the sun into a yellow spot,
but then there are others who, with the help of their art and their intelligence,
transform a yellow spot into the sun.” ~ Pablo Picasso ~
1:01 am
January 18, 2011
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Grant;12408 wrote: No, I'm talking about a beam (not post) buried across the drive, so the posts and the beam form a "U".
I respectfully think you should stick to tools.....;)....Not that it wouldn't work.I've never seen that done and it wouldn't work any better than a well set vertical beam which would be far less labor intensive. The old way of forging a tenon on the end of the style post that fits into a sleeve bearing set below grade with a journal turned into the post for the upper hinge is hard to improve on,you see em all over Europe.
"Be who you are and say what you feel, because those who mind don't matter, and those who matter don't mind."
— Dr. Seuss
4:38 am
NWBA Member
April 22, 2010
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talk about teaching yer grandmother to suck eggs...
Grant knows just a bit about what he is talking about, and beams in the ground is a time honored way of doing this, on larger gates.
Old european gates were generally not powered open and closed, and usually were much smaller spans than todays driveway gates. I have worked on gates that were motorized, that had 26' foot single spans- and while on that particular gate we didnt use a below grade beam, it was engineered quite heavily, with major foundation and post work.
The underground beam trick is very very common in places like the Hollywood Hills, where sag is just not an option.
Anyway, my particular favorite trick for medium weight gates (up to a ton or so) is one that I learned at the San Luis Obismo conference in 1992, from a Swiss blacksmith. I use large, ball bearing leaf hinges, like these-
http://www.stanleycommercialha.....SAH009.pdf
usually up to 4 or 5 for each gate, and then I mill the screw holes into slots- vertical slots on one leaf of the hinge, horizontal slots on the other leaf. This allows you to loosen one side, and adjust for height, or the other side, and adjust for left/right, and, of course, together, you can take out sag- not a lot, but a bit.
This works really well- I have hung a dozen or so pretty big gates this way, and the ability to adjust after final install, fine tune for gap, angle, and height, is a lifesaver.
5:02 am
March 18, 2010
Offline
Actually, it often takes the form of a reinforced concrete beam. Rather easy to dig a trench connecting the post footings. Or, if steel, it could easily be assembled and tested before installation.
Sorry Ries, I mean WTF? I ain't nobody's "Grandma"!:stomp::stomp::bounce:
Thanks Ries!:inlove:
“There are painters who transform the sun into a yellow spot,
but then there are others who, with the help of their art and their intelligence,
transform a yellow spot into the sun.” ~ Pablo Picasso ~
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