Well after 18 months since I cut the first piece of pipe, the gate is finally installed and operational. It is manual operation only at this point as I still have to select and procure an opener.
The original plan to use an idler off a large excavator didn't work out so I had to find something else. I wanted the gate to pivot on one end with no external post or visible hinges.
I found a 7000# trailer axle in the dumpster and cut it in half. I welded some rebar legs to the axle, at Shorty’s suggestion I also added a 12” dimeter anchor plate to the bottom.
The gate weighs 784#s and my seat of the pants engineering told me that 1 yard of concrete would be enough to hold the axle in place with the gate attached to it. I dug a big hole, dropped the axle in the hole and built a form to hold it in place. There's no way I’m mixing 45 eighty pound bags of mud so I paid the premium for a $hort load and ordered 1 yard of concrete.
The axle had drum brakes so I had to trepan the hub out of the brake drum. Then I had to come up with a way to attach the gate to the hub. The ID of the gate pipe is 4.75” and the OD of 4” pipe is 4.5” so my plan was to weld a 5’ length of 4” pipe to a round plate and bolt that to the hub. Then I could just lift the gate up and slide to over the 4” pipe and be done.
The 5” pipe that the gate is made from fit right over the center part of the hub but fell right on the center line of the lug bolt holes so I had to drill new lug bolt holes in a larger bolt hole circle diameter. I figured that the plate that gets welded to the 4” pipe and bolted to the hub needed to be at least 1/2” thick and 7.5” in diameter, but only 1/2” stock I had was 6” wide flat bar. I found an old sprocket in my scarp pile that was 1/2” thick so I cut the center out of it to make the flange from. I cut a register for the pipe in the flange and welded the pipe to it on both the inside and outside. I used sch. 80 pipe for this. I wanted the gate to slip over the pipe easily and the 1/4” difference in ID vs Od would make it to install the gate but too sloppy a fit for actual use. I cut out some 3/4”x1” spacer shims from the wall of a scarp piece of the 5” pipe and weeded them to the bottom of the 4” pipe to make up the 1/4” difference in pipe diameters to give it a nice snug fit. I also made a set of these shims to install at the top of the pipe after the gate was installed.
I had my neighbor Randy come over and run the machine lifting and lowering the gate while I guided it down over the pipe. Everything fit as planned and the gate rotates with absolutely no effort. It might take me another 18 months to install an automatic opener but at least I finally got the gate installed.
