Hang A Fence Gate Right
You can never be too rich, nor have too many gates. Having plenty in your fences, well-placed and right-sized, is a great convenience when unanticipated needs arise. How will the lime-spreading truck get into your pastures after you install that new fence? How will you get equipment into the woods behind your border fence to deal with the tree that came down in the last storm? How can you get your mower from pasture to pasture without driving clear around your property to do it? The answer is "more gates!" And, unless the job clearly calls for a narrow man-gate, we like to use big drive-gates, fifteen to sixteen feet wide, made of painted (not powder-coated) tubular steel. The lighter-weight gates (made from thinner-walled tubing) are less expensive than heavier gates, easier to handle, and perfectly adequate unless, perhaps, you have stallions. Horses do have color vision but they can't see red, so don't fool yourself into thinking that red-painted gates are safer because they are more highly visible to a galloping horse.
Unfortunately, hanging stock gates is becoming something of a lost art. Even some professional fencers don't seem to know how to do it right. Over the long haul, few things are as annoying as an improperly hung gate - one which swings by itself when unlatched, or hits the ground half-way through its arc, or hangs at an annoying and eye-catching angle. Whether you have a professional hang your gates or you do it yourself (and you certainly can - it's easy!), here is our 12-step program for a perfectly hung gate.
1. A well-hung gate begins with well-set posts. The two fence posts on either side of the gate (the 'hinge post' and the 'latch post') MUST be set in concrete. Over time, even a perfectly hung gate will get out of kilter if its hinge and latch posts are set in dirt. Use a post hole digger rather than a hydraulic post-driver to set these two posts, with an auger big enough to leave plenty of room for concrete after the post is in the hole (the auger's diameter should be about 6 inches larger than the post's diameter, or more). The holes should be at least 3 feet deep. It is more important to get the distance between the inner faces of the hinge and latch posts right than it is to perfectly center the posts in the holes. When calculating this distance, don't forget to allow for the extra space required by the latch hardware and the hinges. For the hardware we use, we add five to five and a half inches to the maximum width of the gate to calculate the required space between the inside faces of the hinge and latch posts; your mileage may vary. Err on the side of making this space a little too big, rather than too small - you can always shim up the latch with a length of 2x4 or plywood between the latch and its post, if needed. Place one post in its hole and have a helper hold it as nearly plumb as possible (a 3' carpenter's level is a big help here) while you pour as many bags of dry concrete mix into the hole as needed to half-fill the hole. Poke the concrete with a stick as you pour, to fill any voids which form. When the hole is half-full, pour in about 5" of water, let it soak in for a couple of minutes, then finish filling the hole with dry mix to within about 5" of the top. Add another five inches of water, and repeat one or two times as this water is absorbed. Before the concrete begins to set, make any final fine adjustments required to get the post nearly plumb - but it doesn't need to be perfect. Set the second post the same way, paying close attention to the distance between the inner faces of the two posts. Then let the concrete set for a day or two before you hang the gate. When the concrete is set, finish filling the hole with dirt (or gravel, to keep mower-evading weeds away from the post) and tamp it down.
2. When the concrete is firmly set and the posts don't budge when you thump on them, it's time to hang the gate. If your gate came with screw-in hinge pins, throw them away and go buy some REAL hinge pins at an ag supply store - the kind that push into a through-drilled hole in the post and are secured with two pairs of nuts and washers. This kind of hinge pin allows for easy fine-tuning of your gate for years to come. While you're shopping, buy a spade bit for your hand drill, with a diameter about 1/16" to 1/8" greater than the diameter of the threaded portion of the hinge pin and a length greater than the thickness of your posts.
3. A 16' gate can be unwieldy to handle even for two workers, but the job is much easier if you have a tractor with a front-loader. Weave a rope vertically through the rails at both ends of the gate and tie the rope's ends to form a loop you can slip over the the front-loader's bucket, so the gate hangs freely and vertically when you raise the bucket. This way, lifting, moving, and positioning the gate are easy one-man jobs.
4. Start with the bottom-most of the gate's two hinges (the bottom hinge-loop is usually welded onto the gate, but the top loop is clamped on and is vertically adjustable, so the bottom hinge is the one whose placement is critical). Determine the distance above ground the bottom hinge pin needs to be set at in order to permit the gate to swing through its complete arc without hitting the ground anywhere - a well-hung gate hangs in the air and swings freely. If you live in an area where the ground frost-heaves in freezing weather, add an extra inch or two of clearance so the gate will swing freely in winter, too. Err on the side of hanging the gate a little too high, rather than too low; your horse isn't going to crawl under the gate. Drill a hole at the correct height clear through the hinge post with your spade bit, as nearly horizontally as possible. Drilling from the inside face of the post toward the outside face helps insure the hinge pin will end up right where you want it.
5. Run one nut and washer to within an inch or two of the vertical pin end of the hinge pin and insert the threaded end through the hole (from the inside face of the post); if it's a snug fit (which is good), bang it in with a rubber mallet or with a hammer and a block of wood. Secure the hinge pin with the other nut and washer, snugged down to the outside face of the post. The vertical part of the hinge pin should be pointed UP. You'll fine-tune its projection from the inside face of the post later; for now just tighten the nuts down good while leaving the pin pointed straight up.
6. Determine where you'd like the gate's top-most hinge loop to go. It should be as near to the top of the gate as possible while still leaving several inches of room to adjust its position vertically up or down - that is, it belongs mid-way between the gate's two top rails. Measure the distance between the BOTTOM of the gate's bottom-most hinge loop and the TOP of its top-most hinge loop when the top loop is approximately centered between the gate's two top rails. Add to this the distance between the flat horizontal face of the hinge pin and the CENTER of the hinge pin's threaded rod. Measuring up from the flat horizontal face of the hinge pin you've already placed, mark this distance with a horizontal line on the inside face of the hinge post.
7. Using a 3' carpenter's level, draw a vertical line on the inside face of the hinge post as nearly as possible plumb to the center of the pin you set in step #5, above. This measurement is critical for a well-hung gate, so get it plumb. Where your horizontal and vertical lines cross is where you should center the hole for the top hinge pin. If it is plumb but a little off the center of the post (which happens if the post is not perfectly vertical), don't worry about that; plumb is what counts. Drill the top hole, again as nearly horizontal as possible. Drill from the post's inner face toward its outer face for greatest accuracy.
8. Insert the hinge pin in the top hole as you did for the bottom pin in step #5, but don't tighten its nuts yet. Here's the step which separates the pros from the amateurs: counter-intuitive as it might seem, leave the vertical pin part of the top hinge pin pointed DOWN, not up. This way, a horse can't lift the gate off its hinges, either accidentally or on purpose. You don't want a panic-stricken horse running around your pasture with a 16' gate hanging around its neck!
9. Using your carpenter's level, determine how far out the top pin needs to project from the post in order to be perfectly vertically aligned (i.e., plumb) with the bottom pin. Make it so, then tighten the top pin's nuts good and tight.
10. Move the gate into position (either by hand with a helper, or hanging from your tractor's front-loader), and slip the gate's bottom hinge loop onto the post's bottom hinge pin. Slide the gate's top hinge loop all the way up onto the top hinge pin, make sure it's vertically plumb with the bottom loop, then secure it in place by tightening its clamp good and tight.
11. Release the gate and see how it hangs. With the carpenter's level on its top rail, make sure it's as nearly perfectly horizontal as you can get it; adjust the projection of the top and/or bottom hinge pins to make it so, then tighten the hinge pins' nuts as tight as you can get them without splitting the post. When perfectly hung, a gate will remain motionless at any point in its arc.
12. Install your latch hardware. There are too many styles for us to discuss here; pick a style that even the smartest horse can't open but a person easily can from either side of the gate - the best latches fully support the weight of the gate's free end when it's closed. If the gate doesn't quite reach the latch, shim the latch with a couple of thicknesses of exterior plywood or a short length of pressure-treated 2x4 screwed to the inside face of the latch post. Finally, if the threaded ends of the hinge pins project more than a couple of inches from the outside face of the post, for safety's sake cut them off with a hacksaw, but leave maybe two inches of thread projecting beyond the outside nut; with time your gate will sag a little and start to miss its latch, and this excess thread will allow you to adjust the projection of the top and/or bottom hinge pins to level it up again.