Avoiding binding

[Joel OF]

Hello folks, I have some questions relating to the ground level tenons & sockets on strap & journal gate hinges. I haven't used this type of hinge system before but am due to use it on some gates I'm making soon - close up from design attached. In the accompanying sketches I have exagerated the angle of the gate back stile for sake of explanation.

Due to site circumstances the socket will not be independent & will be welded to the gate hanging post, meaning the only adjustibility will come from the top hinge.

In the event of needing to adjust the gates angle it will cause the tenon in the socket to tilt. I want to avoid the tenon binding on the inside of the socket & also avoid the tenon shoulder binding on the top of the socket. Is it common practice for the holes in the sockets to be flared & the tops of the sockets to be rounded over? I could alternatively make the shoulders on the tenon rounded back & taper the tenon.

[Glenn]

The large issue I see is the socket filling with debris, dirt, and water. From there corrosion is accelerated. Metal to metal movement makes things worse.

Is the top hinge the only adjustment to correct the gate sagging over time, or children playing?

[Joel OF]

Pretty much, unless you shimmed between the tenon & socket to bump it up in height. For the gates' site it's the best hinge arrangement.

[Marc1]

I wouldn't make a socket that low at ground level. Keep it well above ground.

As for leveling, if that gate with those hinges sags, it is the post that is too weak or has no bracing to keep it vertical. If you adjust the gate to fit a crooked post, the question is how much do you adjust before you fix the post? 

But to your question, you are overthinking it. The tenon needs a healthy dose of play to allow for some misalignment. You don't need to think of it as a machinist would. 5 degrees angle in that short tenon means very little and you don't want a tight fit whatever you do. 

And I don't make the hinges that way. For a little gate like that I make the bottom hinge with a 5/8 flat bar, bent at 90 and riveted or bolted to the post. A sloppy fit for the tenon and you can wiggle the vertical as much as you want. However, don't forget that if your gate is not parallel to the post it will show. Even a small difference will be noticeable so you have to work on the post not the gate.  To bolt against a hollow steel post, I like to use SS inserts if the wall of the post is thick enough. 

[billybodgeit]

Hello Joel

You are over thinking it. The bottom socket is closed, not a through hole as you have drawn it. The journal is longer than the socket, it is the end of the tenon/journal that bears on the bottom of the socket, not the shoulder. Binding is not a problem as the fit is not a precision engineered one. The gate would have to be drastically out of plumb for that to occur, in which case you would have far greater problems.

With regard to wear, this is less than pintle hinges. It is a tried and tested method used for hundreds of years. There is similar method which excludes water and dirt ingress to some extent by having the socket formed in the bottom of the backstile, the journal located in the ground.

Billy

 

Just an add on. I have in the past fitted grease nipples, by drilling up the centre of the journal and then cross drilling the stile. You can then tell your client to add the greasing to an annual maintenance regime. As if they ever will.

Billy 

[Ranchmanben]

I always like gates to be at least a few inches above ground so hinges don’t get clogged up and the gate doesn’t get hung up on a pebble. 

[Marc1]

You can make a bottom hinge on the same principle of tenon bottoming and shoulders free, by making a U with thick flat bar, drill the top side of the (horizontal) U and make the tenon bottom on the lower side of the horizontal U. The tenon will pivot against a small surface on the flat bar and the top side of the U will hold it in place. How you fix it to the post depends from materials used for the post. 

If it is above ground, no dirt issues and still work on the traditional principle of pivoting on the tenon. If you want the bottom hinge to be independent from the post, make a stirrup again using flat bar, this time an inverted U with a little saddle across the U, 1/2 inch below the top side and set the straight sides of your inverted U in concrete making sure you have a bit of clearance to avoid dirt build up

[Joel OF]

Thanks for the replies folks. The horizontal drilled U sounds like a neat trick Marc1 - and the tenon length VS socket depth info was golden  billybodgeit - I had assumed the sockets were really a tunnel so that water would drain through. The socket being above ground level makes complete sense.

The posts will have square plates welded to the bottom & they will get bolted to concrete pads. The plates can be shimmed to level up the post.

I think the socket will just be welded to the 100mm round hollow post, 5mm wall. For the top hinge I'm going to weld in reinforcing SHS to prevent the post from crushing as the nut is tightened up. The first part of the journal shank will be square (to prevent rotating) before it's rounded up & threaded to allow for adjustment on the backside of the hanging post.

[billybodgeit]

Joel

The shank of the top hinge, as you refer to it does not have to be square to stop rotation. Once the strap is fastened round the journal it cannot rotate.

In the situation you are describing if you leave the shoulder short of your intended length, say 2-3 mm, you then have adjustment to allow for drop, both when you are fitting and into the future. I used to go armed with various steel shims to take up the gap, I now use lead shims and tighten up until I'm happy and everything is plumb. The excess lead is then trimmed and caulked. As you are fixing to a tubular post this will produce a neat joint on a curved surface.

[Joel OF]

1 hour ago, billybodgeit said:

The shank of the top hinge, as you refer to it does not have to be square to stop rotation. Once the strap is fastened round the journal it cannot rotate.

Very true. I just thought it might help reduce the nut on the backside being "worked". Although they're quite different I'm mentally scarred by the half collapsed farm gates I constantly see as a result of the nuts on their adjustable threaded hinge pins working themselves loose & so the pins rotate.

Yes I'd planned on purposefully making the shoulder on the shank too short & packing with shims for adjustment. I'd planned on rolling some 2mm flat bar to match the curve of the hanging post.

I'm also making some railings to go either side of the double gates - they actually funnel in towards the gates. The gates have to hook open onto the rails but the site is so uneven there's little chance of me having a successful mock up in the workshop so we're having a dummy run install before weatherproofing to check the fit.

Cheers for your words of widsom.

[anvil]

I workedon a similar gate with two other folks but used a slightly different solution. Same hinge setup top and bottom

Hope my terminology is correct.

We used a sealed thrust bearing on the bottom hinge. We added a zerk to the bearing and four large Allen bolts around the bearing housing for adjustment of the bearing both left/right and fore/aft.

The primary purpose was to keep the alignment of the two gates in plane. This is far more visible than the small change out of plane in the stile and kept the latching system aligned as well.

An oiled bronze bushing was added to the top hinge as a "wear point" that prevents binding and over time is easily replaced.

Bottom Bearing design was done by Russ Sweider, Rowe, N.M.. Hope I spelled his name correctly.

Our setup would fit your drawing to a tee.

For what it's worth, this was a Francis Whitaker masters workshop held at Rowe,N. M. We discussed the esthetics problem mentioned above and added in the practicality of the latching system. Also discussed was gate sag in forged gates. We decided esthetically that the bottom line of the two gates and the vertical line where they came together was more visible than that by the gate posts.

As for sag, Francis indicated that no matter how well designed(diagional bracing and compensating for estimated sag) over the first year or so the mechanical nature of traditional joinery would work together and creat "jam" joints which would prevent any long term sag. However, this settling in would still cause some unknown amount of sag. The bottom hinge bearing setup solved this short term problem.

Long term sag would happen primarily from the wear on the oil bronze bushing on the top hinge. This was expected and would happen over long periods of time. This was adjusted, again, by the bottom Allen bolts. When the wear on the oiled bronze bushing became severe, it could easily be replaced.

Lol, after these many decades, it's very cool to be able to bring a little of Francis to all of you here. 

 

[Joel OF]

Thanks anvil,

Unfortunately I have no knowledge whatsoever of bushings & bearings as I don't have any mechanical/engineering/agricultural background, so ways to include these sorts of things in designs goes well over my head.

If a broze bushing is effectively a tube, how do you get it around the rounded up section (the top hinge) when you can't physically drop it on? Is it in 2 parts? Also, would a bushing required a shoulder to sit on to prevent it sliding down? 

Unfortunately because these gates are going in a public space all the fixings nuts are going to be shear nuts, so any worn parts can't be easily swapped out for new ones. I think this time around I'm going to have to rely on good spirited local public to ocassionally grease the hinges - top & bottom.

[anvil]

On 2/19/2018 at 10:19 PM, Joel OF said:

If a broze bushing is effectively a tube, how do you get it around the rounded up section (the top hinge) when you can't physically drop it on?

Sorry, I posted earlier but must have not hit the post button.

Yes, cut the bushing in half.

Bearings are a good thing to become familiar with. I use a oil bronze bushing on the top hinge of my fireplace doors and a simple bronze washer on the bottom hinge.

When your doors have glass and iron details, they are pretty heavy and the iron on iron wears pretty fast. Far better to replace the washers than to repair/ remake the hinges.

The setup for bearings is actually pretty easy once you understand what's happening. If you are interested, for future knowledge, let me know. 

 

[Joel OF]

22 hours ago, anvil said:

The setup for bearings is actually pretty easy once you understand what's happening. If you are interested, for future knowledge, let me know.

Yeah definitely interested to see any pictures you have that help explain the process and options. Always useful for future reference!! Cheers

[jlpservicesinc]

If I understand you correctly the easiest way to do it is just make the top hinge pintels adjustable with spacers behind the main shoulder.. 

In the olden days gates and even water locks used metal on metal but were used often enough not to create a problem with rusting..  The gate I hung 20+ years ago still swings as easily as it does today as when it went up and it get 0 maintenance.. 

If you are really concerned with rusting or this type of problem just design the gate to have a replaceable pin Easy enough to design into the project.. It's not today or even in the next 30years that will play in.. But for the longer time there after and with mild steels gates need care..  The barrel or hinge receiver on the bottom made from bronze or wrought iron would offer a longer service life..  

Corten might be something you want to look into for a material.. 

As for gate sag..  On short gates if you take into consideration the standard sag ratio they may never sag to even reach level until you get a few dozen kids swinging on it.. 

Longer gates in relation to height are where you can have a full 2" or more of sag at the other end and then having the design of the gate becomes even more important..