Welding a steel driveway gate pt. 2

The actual gate part

Part one of this series covered my first attempts at concrete work and the welding up a nice set of steel posts and rails that add some class to the driveway and act as a hopefully overbuilt anchor for the remarkable frost heave we get in the spring. No gate sag is going to happen on my watch. Find part 1 here:Custom driveway gates part one

Now while I wait for the rain to stop it's time to get some hinges worked out.

Building the hinges

I've heard rumors that you can just buy weld-on gate hinges. That may be true, and for the weight these gates turned out to be that would be fine, but I'm fairly sure you cannot just go buy hinges like this:
gate hinges

Ok I guess I kinda spoiled the end result already. I got excited, since this just all went exactly as planned. See, one of the reasons I wanted a 16 foot wide entry way is I have some more pipe parts that are 16' long already. This could make for a very stout single-swing gate that would have made keeping everything level and building a gate opener much simpler. That was more 1/8" wall pipe and at 16 feet long I planned on having to support a fair bit of leverage on the post.
When I decided to have an 18' wide entry however, that idea went in the bin. I begrudgingly accepted that I was going to have to build a dual-swing gate setup, with dual openers, dual hinges, etc. What I wasn't giving up on was my super-stout hinge idea, I'm just going to have to make twice as many.
So each hinge is going to take 4 parts, 3 of which I get to build myself:

  • a pillow block bearing
  • a mounting block to attach the bearing to the post
  • the hinge pin for the gates
  • a spacer block to attach the hinge pin to the gate

Self aligning bearings

Pillow blocks - as these bearing-in-a-cast-housing parts are called - are not just a simple way of being able to bolt a bearing onto a flat surface. The outermost bearing race has a wide radius that can slide and pivot inside of that cast housing. This gives optimal bearing life even when installed on surfaces that are not exactly in alignment, especially on heavy equipment when parts may slowly warp, bend or move with stress and age. Mostly I'm talking about bearing life in commercial equipment here: when a bearing runs all day every day, an even force across the bearing's surface is essential to long life. A bearing pressed into a bore slightly sideways or assembled slightly out of alignment may turn freely today. It will probably turn freely next month, but it can likely come to a premature end and a screeching halt sooner than it should on conveyor systems and the like that must run all-day-every-day.
a pillow block
Now a gate hinge will never see heavy bearing use, speed, or temperature, but it will make sure the hinge turns smooth and straight even if my hinge-pins don't end up perfectly co-linear when welded on the gate. One last reason for using these instead of a simpler, cheaper hinge option is that I already have a huge pile of them waiting to see use outside of their cosmoline soaked packaging.

Mounting blocks

Pillow block bearings are great but kinda hard to bolt to round surfaces. I wish I had gotten a proper picture of the mill setup for this cut but I was too focused on a clamping setup what would cut the radius in the steel tube and not launch the part or the fly-cutter off the milling machine and through the window.

So here's how it turned out:

mounting blocks
A 2" radius was slowly milled out the back by plunging a fly-cutter downwards with the mill, about 30 thousandth's of an inch at a time. This makes for a great fitup between the block and the post and helps keep it perfectly aligned with the post for welding. On the other side some oversized holes to weld in the nuts and some caps on the end to keep the wasps from building a home in there.

Hinge pins and hinge pin space blocks

hinge pins
Not much to say about the pins here really. Some quick lathe time with some 1.5" hot-rolled bar gets me some hinge pins stronger than most of the gun-safe door hinges I've ever seen. The spacers are needed since I'm not going with the single 16' gate after all. I've got 8' pipes to work with instead to fill an 18' gap. The mounting blocks and hinge pins take up some of this extra space but I made these spacers from some more square tube to take up a few more inches and leave only about a 2" gap between the gates when installed. Just roughed out a radius on each end in the mill and TIG welded them to the hinge pins, then weld that to the gate.
spacer blocks
That little flare you see on there exists for two reasons. One, a 1" roughing end-mill is the biggest I've got and two, it lets me keep a little more wall thickness to weld to that if I cut that end to the razors-edge it would be if I sunk a 1.25" endmill to a full radius into the tube.

Hinges complete! Time to start a gate to go with them.

Starting the gates proper

Since this driveway entrance isn't even fencing the whole front of the property it seemed kinda pointless to make some kind of livestock or dog-tight gate setup. I decided on more of a slightly upscale vehicle barrier style. Since I have to make two, it would be nice to have an elevated, flat workspace on which I could make some fixturing to keep both gates identical. Turns out I have one- it's any flatbed truck or trailer with a wooden deck!
gate frame
After committing to some dimensions and cutting the 45's on the ends of the pipe I carefully laid it out and squared everything up before screwing scrap boards down around the perimeter to hold everything together. First I welded both rectangle frames, and it was here that I discovered some of my pipe had a slight curve to it. Hmm, what to do about that... oh, I have a pipe roller I built years ago, and it gets used so little I sometimes forget I have it.
pipe roller
straightening pipe
It's hard to see the curve in the photo but set on the ground the worst pipe had about a 1" rise in the middle. I built this pipe roller years ago and it's seen some use with flat bar and 1" tubing. I built some 1.75" dies and thought that could be enough to make some neat curves with the .040 wall pipe. HA! as if. There wasn't much curve to the pipe at all before it was too difficult to crank and the sides of the pipe were bulging. Ok, so non-hydraulic and hand powered isn't going to cut it there, but today I find a use for those dies anyway. Gently straightening a bent pipe went pretty well, slowly increasing pressure as the pipe was rolled back and forth through the machine.

With that straightened out the frame was welded and I could start in on the diagonals. These were just cut to 45 degrees and spaced evenly, with the ends crushed down to close the gap between the diagonals and the outer frame. This mostly worked fine but a couple cuts still got weird and required either grinding or some extra fill-in with the mig welder. Overall I'm quite happy with how the welding went.
welding fixture

Installation, finally

Now it's time to haul the parts and welder back out to the road and really start seeing everything come together. First step was to decide on the exact height of the gates, and once again this proved tricky with the slope of the road. On the downhill side I propped up the gate with the top a little lower than chest high. I ran a stringline underneath that, and once again I started thinking my string level was broken. The top of the uphill gate would have been barely over hip high installed like that, this seems to be a very deceptively steep slope I live on. I held a gate up with the scissor lift table and ran it up and down till I found a height that looked right. I made some marks with soapstone and started leveling and squaring up the mounting blocks.
welding mounting blocks
Despite the haze that turned into a pretty warm afternoon. I had a long ice tea break and then came back to this.
welding wip

The red lift-cart made it easy to support the center of the gates while aligning everything and installing. Makes a good mobile workbench too, and is great for sliding really heavy things onto or off a truck, trailer or work bench. If you do much mechanic or metalwork I highly recommend getting one, it's the unsung hero of my shop.

The lower two pillow-blocks were bolted on, the gates set in, then slide the upper pillow-blocks over the pin and lift into place. Much as I love overbuilt equipment having these gates so lightweight made it pretty easy on the installer. hinges complete

Another advantage of the tall pins and long spacers was that the gates completely clear those square tube mounting blocks; the gates can open well past 90degrees inwards and will even fold back against the fence when opened outwards. Plenty of room to get a truck and trailer in and out here. the gate is complete

Alright, time to enjoy that very satisfying feeling of a well executed project. The hinges are well balanced, level, and swing super smooth. Only two tasks remain:

  • paint it
  • built a latch

By 'build a latch' of course I could never be content to just slap a hook and clasp on it and call it good. This deserves a proper remote gate opener, and I can't be content to just buy one of those either. Designs are coming together, part 3 coming soon.


In case you missed it

Part 1 is available here: Custom driveway gates part one

Update

Part 3 is up. Building the controller: Driveway gates part 3