There is plenty of timber around my cabin site. But, especially green, it will be very heavy. So, I decided to build a log arch that could be pulled by an ATV, side-by-side, tractor, or skid steer.
A log arch is essentially a trailer to suspend logs above the ground so that they can be moved with less effort and disturbance compared with dragging.
The main raw materials for my arch were salvaged from an old utility trailer contributed by my friend Nate Nibbelink. Here is a picture of the trailer when I first brought it home.
And another after I had removed the rotting sides and bed and pressure washed it.
My friend Reese Walker was my primary parter in the arch project. Reese works for a metal fabricator and has a portable Lincoln Electric arc welder. Here’s a photo of Reese while we were planning out the project and the sketch we made that guided the design.
As you can see from the photos the front of the trailer had been pre-formed into a rounded rectangle, which we kept intact to use for the main arch. The trailer itself was not made from channel, but metal plate that had been bent into a C-shape.
Our first task was disassembling the trailer into usable pieces with a cutting blade on the angle grinder. We worked two evenings a week from 6-10pm (with a break for dinner) for about three weeks to complete the whole project. Cutting up the trailer was a good two sessions. The metal frame usually went pretty quickly, but we went through quite a few wheels on some of the bolts. Also, the axle was a solid iron bar an inch and a quarter in cross-section, which took quite some time to get through.
We cut the trailer tongue about six inches behind the coupling to use for the upper tongue of the arch. Here, we had to compromise between the overall length of the upper tongue, which determines the maximum length of log that can be fully suspended, and the strength of the braces. The shorter the brace the longer a log can be carried, but at a cost of reducing the stiffness of the front tongue assembly. Not being structural engineers (or engineers of any sort), we just guessed, taking advantage of whatever opportunities the materials presented. For instance, we welded the lower front brace to the front post at a place where there was already a gusset welded into the other side.
As shown in the next image, we used a step ladder to stabilize the tongue while we worked on the arch. One of the biggest challenges we encountered was the compound miters needed to fit the rear struts to the frame of the arch. We made these struts out of one-inch scrap tube that Reese had. To fit the struts, we first measured the angles individually, cut with the angle grinder, and then iteratively grinding and fitting and grinding and fitting until the fit was sufficiently close to take a bead.
Welding the struts onto the upper tongue of the arch.
The arch already had a horizontal member welded into it. Here’s a picture from the back of the upper tongue showing how we welded the tongue to this member. You can also see the completed struts in this picture.
We salvaged hubs, wheels, and tires from the same trailer. For an attachment point to the arch, we first welded a plate at the base of each leg of the arch.
To this we welded the axle on both sides and from the bottom. We welded the axle before cutting, which provided stiffness while we were working with the material and naturally aligned the two wheels, which would have been a challenge if we had cut the axle first.
Throughout, but especially in the arch itself, we added gussets for stiffness. We fabricated the front vertical post from another trailer scrap adding braces made from one-inch tube — a large one connected to the lower tongue/coupling and a smaller one connected to the upper tongue.
We spent most of an evening creating the bracket that would hold the snatch block suspending the log. During winching, this assembly will have to hold the entire weight of the log. We had two smaller brackets salvaged from the trailer, which we first welded together to make a plate of double thickness, which we then welded to the upper cross member of the arch. We reinforced this plate with two pieces of angle. We were worried that concentrating all the force of a log on the center of the arch might cause it to buckle, so we stitch-welded a piece of one-inch tube to the underside (unfortunately, I don’t have a picture of the tube) to stiffen the upper cross member. Finally, we added some clevis hooks and a roller. The purpose of the clevis hooks is to hold a chain for securing the log while in tow. We installed the roller because we realized the natural path of the wire rope would run over the edge of the upper tongue and we didn’t want this to cause fraying. For a roller, we repurposed a caster wheel made for industrial carts purchased from Amazon. I don’t have photos of the clevis hooks and roller at this stage of the build, but you can see them in the finished product at the end.
To finish the project, we cleaned it everywhere with Goof-off and then primed and painted it with Rustoleum paint brushed on. We used grey for the arch and black for the wheels, including a spare that came with the trailer. We finished the build with a 3500-pound two-directional hand winch.
Not counting our time (about fifty person hours hours altogether), costs for the project totaled $172.01
- Snatch block ($36.95)
- Shackles ($11.99)
- Roller ($10.99)
- Clevis hooks ($21.99)
- Winch ($65.90)
- Paint and primer ($24.19)
Here are some more pictures of the finished project.
Moving a heavy log - The Side Of A Mountain
[…] weekend I was joined by Reese (who helped with the log arch) and his brother Kit. With clear weather, we decided to dive right into work. The highest priority […]
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