Built a log arch to support my log cabin build in north Georgia. Lots of ideas taken from this forum so posting here for posterity, comments, and suggestions for improvement. Thanks to everyone who has shared their wisdom on the forum.
For more on the cabin build, including a more complete post on the log arch, see my blog (link in my profile).
I started with a utility trailer donated to the cause by my friend Nate. Here are pics from when I picked it up and after I hard torn off the rotting box and pressure washed it.
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The trailer had been constructed on an arched frame which we naturally salvaged for the arch itself (after reinforcement). Here's my buddy Reese cutting up the frame.
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Reese had some scrap 1" tube that we used for struts. Getting these compound miters right was probably the most challenging part of the build.
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Steel tube from the trailer was used for the upper tongue of the arch, which we welded to the existing horizontal member of the arch.
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We welded some steel plate to the arch uprights to attach the axles (hubs, wheels, and tires all salvaged from the trailer). We also reinforced the arch with some gussets placed every 12" or so inside the upright members of the arch.
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Here's a picture of the arch upside down so we could weld the axles on. In fact, we welded the full axle on both sides and then cut the middle piece out. This helped to stabilize the whole assembly for welding and also kept the two wheels aligned.
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We got our first look at what the final product would look like that night.
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Various pieces of scrap were used to make a bracket for a snatch block. We reinforced the bracket with a couple of pieces of angle. We reinforced the arch itself by stitch-welding a piece of 1" tube to the underside of the top of the arch.
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We spent another evening or so working on the coupling, lower tongue, and forward upright. You can see that part of the design in the pictures of the final product, coming up next. We finished the project with some clevis hooks, a trolley caster repurposed as a roller, some grey Rustoleum, and a boat trailer winch. I plan to pull it with a 6x6 UTV. Comments and suggestions welcome. Thanks for reading.
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Post Hole Digger?
How many acres in N GA and what sort of build?
the arch portion itself would be stronger if fully boxed in (make rectangular tube, instead of intermittently reinforced C channel. and the arch itself is rectangular and under any side load could fold up. triangles are the strongest and you could add to the underside to follow the round shape of a log, and reduce the parallel (foldable) segments of the "arch". It overall looks great. some of the welds look a bit "cold" in the pic, so make sure the heavy duty segments have good penetration. might be hard on the lightweight stuff. If a wheel catches a stump, and the C channel deforms (twists), all the strength in that segment will be lost forever. adding back the strap you removed from the tongue would stiffen that up. and I would consider more triangles in the upper rectangle of the arch (truss). you did a nice job, and it may work well as is. if you plan to really use and push it, I hate to see it fold up into a pile of scrap. what size logs do you plan to use it for? very nice use of materials. good fabrication.
Looks like you had a great time repurposing that trailer.
Wonder what you will build next?
Welcome to the forum, lot of clever company here.
Looks good. Your small welder will have just a little more snot if you preheat thicker pieces with a bottle torch first. Not a criticism.. Theres only so much you can do with a 110v machine.
Now go put it to the test and see what twists off first.
Doc had it right about triangles for hollow pieces, but solid is the strongest. HOWEVER, the inherent weight problem with it (solid) usually overrides any benefits that you get out of it in a LOT of places, BUT, not all! I'm the son of a structural steel engineer, so I learned about quite a bit of this kind of stuff because it's what I was around so much growing up. It's hard to escape Dad's preachings about that type of stuff, even though bunches of it DIDN'T stick, but some DID.
The biggest problem that I have is what my choices are for what I'm working with (and coin). I always consult one of his best friends that's still kicking and in that business to this day. It happens that he likes me too, and I often hang out with his son.
Suggest that you add some pull braces from the end of the tongue to the axle at the base of the upright of the arch. That will strengthen the arch leg and act as a shear to help slide around stumps/logs, other obstructions.
If you are using that on logs of any size, I would box in all of that c channel and add some angle bracing.
Thanks to everyone for the feedback -- very much appreciated. Will let you know how it goes with the arch as well as further mods.
Cabin will be 12x20 made from timber on the property (40 acres, mostly steep) that I plan to saw. There are a few photos of the property on the blog.