The side gate into our yard has always been tricky. Due to geometry constraints, the only place to mount the latch pin was on a slightly wobbly post, and that wobble makes it hard for the latch to get a positive grab. So any time somebody goes through that gate, there’s a significant chance it won’t close properly behind them. And since it’s almost exclusively service people using that gate (meter reader, Amazon deliveries, etc.) it can take us a while to notice when it gets left open.
This week, however, it was the dog who noticed. So after spending a stress-filled half hour tracking her down on our busy street, I decided it was time to address the problem.
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Inspection revealed four distinct components to the problem.
1: Leaf Clutter
The gate is in a narrow alley between the garage and the fence - a perfect stall zone for wind - so it’s constantly filling up with dead leaves. No matter how often I rake them out, the cyclonic action fills it up again 20 minutes later. Over the years I’ve discovered that if I just let them accumulate to a depth of 2 or 3 inches, they won’t pile up any deeper. (Wind is weird.)
Unfortunately, if I leave them there too long, the bottom layer turns to muck - sometimes thick enough to interfere with the gate. So step one was simple: Clear out the leaf muck.
2: Unclaimed Freight
While excavating to get back down to the paving stones, I got another surprise - there was actually more than just leaf muck under there. A length of 2" ABS pipe was lying against the side of the house, hidden by the leaves but protruding just far enough to rub against the bottom of the gate as it tried to close.
We often leave things there for freecycle pickups and it turns out the woman who said she wanted the ABS pipe last fall never came to get them. So this step was also an easy fix, and that pipe has found a less intrusive place to wait for the next freecycler.
3: Obstructed Hinges
I have no idea how long that gate has been there, but it wasn’t new when we moved in 22 years ago, so the hinges have had a long time to pick up grit and twigs. They’d also been painted over at least twice, and while the galvanized hinge metal itself still seemed in decent shape, the screws holding them were contributing a steady rain of rust particles to the aforementioned grit.
All these effects, taken individually, were trivial, but added together, they provided a nontrivial amount of friction that was gently impeding the smooth operation of the gate. Not enough to make it difficult to close, but more than enough to keep it from swinging closed on its own, which used to happen regularly when the gate and I were both 20 years younger. My knees can’t be easily replaced, but those hinges? Damn right they can. So it was time for an upgrade. I picked up a new pair, and to enhance the closability even further, this time I went with the spring-loaded variety shown above.
4: Capture Action
Finally we come to the place where the rubber meets the road: the latch. It doesn’t matter how much resistance I remove from the gate travel, if the latch doesn’t actually latch, the system won’t offer a reliable dog barrier.
If you try to visualize a gate latch, chances are good that you’ll imagine the right one. It’s a ubiquitous design. One might even call it the definitive gate latch. But common as it is, there is still one flaw: if the pin it’s trying to grab wiggles even a little bit, it won’t go into the narrow throat that’s trying to capture it, or it will strike at an angle and bounce back. And with that wobbly post still in the mix (for reasons I won’t get into) the situation was begging for a more angle-tolerant latch design.
I looked in all the usual garden gate latch stores, but didn’t see anything that fit my situation. I figured I’d end up designing something myself, but before investing the time, I had a look on Printables and found something very promising.
Designer’s photoAs you can see in the designer’s promo image, it was originally intended to hold gates open, not closed, but that’s just semantics. What attracted me was the simplicity of its design, which seems extremely tolerant of pin alignment issues. Without a latch lever to push out of the way, the angle of approach can vary significantly here without compromising the grabbing function.
My first print (in PETG) was almost perfect, but in the original design, the gap between the two capture hoops proved to be a bit too narrow, requiring too much force to secure the pin. Either my gate pin is beefier than the pin it was designed for, or my filament is stiffer, but either way, the fix was the same. I edited the STL file and increased the separation. My pin is almost exactly 1 cm in diameter, so I bumped the gap from 4 mm to 8 and everything now seems to work like magic. The hinges pull the gate closed with enough force that the latch grabs the pin and holds it there. Every. Single. Time.
Follow-Up: The latch broke when it slammed shut during a heavy wind. Upon inspection, the compliant hoop that grabs the pin is a bit thin. I’ll try beefing it up to see if it can take more of a beating.
Contingency: If this one also breaks, I’ll redesign the model in two parts, with interchangeable hoops. Then I can try different sizes and materials without replacing the entire unit.
