Oh yes, very valid point. I was going to do them in 3" sch 40 pipe, and then build several heavy gusset structures to take the load. Almost bordering on a lattice boom. The trailer is made from heavy steel (1/4 inch), and with my extra supports should be more than adequate. I'll likely also do repads to spread the load, so it'll be pretty bomber. Here's a picture of the trailer, it's only 5 x 10 on the floor, but will tolerate very high loading because of its existing rails, roughly 4 feet high already. I will be adding some removable rails in the front and back (i want to still be able to haul super long materials), and may even make them higher yet.
Just giving you a hard time. My "art" skills are a running joke at work, and y'all have seen my pictures. A good phone camera helps me a lot, but I don't currently have a good camera.
As promised, horrible drawings, nothing to scale. My kids were impressed tho, but that doesn't mean much because they can't draw yet either. I didn't show the guylines/backstay, because it would only somehow make the drawings worse, but the gin poles will be guyed front and back, anchoring them in place. In use they won't be able to move at all. To change between loading and unloading, I'll have to add the extra pulley and rope, shown on the final picture. Still debating on wire rope size, i may want the extra length afforded by using 3/8 for using as a yarder, and doubled it would still lift 2 tons, which is quite the load on the trailer. 3/8 would likely wear better as well, since I'm going to use 4 inch logging blocks. Going to have to see if i can get a 3/8 wedge ferrule.
That's a picture from 3 phones ago, i really don't usually take pictures of anything other than my kids. I'll do better moving forward.
Thanks man, i appreciate it. Even if i don't use 3/8 on this build i likely will for a later one. Yeah I'll be doing pictures. I looked up the winch i have, and the difference between the 2 is only 20 feet for 7 layers, which would still be over 4k line pull. I have some 7/16 ferrules so i might just use those after all, anything over 150 feet would be more than enough i think. I'll have to do some math to make sure I'm putting a big enough engine on it, and I'll have to make sure I'm mounting the 1st pulley the correct distance for the fleet angle.
Alrighty, so i only had a couple hours to work on it today, but thanks to my little cold cut saw i got quite a few cuts done. I dug out what pieces i think i need out of the scrap pile, including way too much pipe, some heavy small diameter square tube, and a truck axle. I've decided I'm doing 3" pipe uprights for the back where the gin poles attach (super overkill but will be easy to fab), 5 foot tall, with 2 inch pipes saddled on at the floor, halfway up, and at the top. 3 inch pipe will slide over it, and the pipe in pipe will be my flexible connections. I have more pipe than plate, it's faster to cut with the cold cut saw rather than laying out and torching holes, and since it's all in compression it should be more than fine. The front stiffleg will be in tension, but i still think my pipe in pipe will be more than adequate for that one as well. I might use some schedule 80 3" there tho, just to be safe.
I got all the 3" pieces cut out, including the swivel end pieces. I'm going to use 2" for the gin poles and support poles, and 1.5" for the stiffleg in front that's in tension. The truck axle fits the logging blocks pretty well, so that and the heavy square tubing will be my connections for those. The poles will need to be mitered, as will the support gusset pieces for the rear uprights, which will go quick with the saw i have. The 2" pipes that the poles will attach to are weldable to the 3" uprights with square cuts, so that's the why on the 3" pipe there (and will look more correct to my eye lol). I'll need to go to tsc and buy a bunch of large hitch pins, which will lock the pipe on pipe hinges together after i punch some holes in the 2".
The winch has a 7" drum, so to get the ideal fleet angle i need to be roughly 13' - 6" to the first pulley. The front support structure is going to be in the inside of the bed, so it can angle towards the back to give room to hit that measurement. This will also help on the drifting, because the closer the 2 rigging points are the lower the forces. The front support structure will be basically another gin pole setup, and I've decided on 10 foot long uprights. This will put me roughly 12 foot from the road, which is under legal height. The gin poles will be somewhere between 12 and 15 feet, and fixed length since they don't need to fold flush into the bed or anything. If i go 15 foot i should be close to 20' off the ground on the highest setting, 5 foot from the back. That should be good enough for now.
A bit. Got to run to stl today, but i couldn't sleep last night and did a bunch more thinking on stuff. The using ropes idea was bothering me, since they will be in the elements all the time they would likely degrade very quickly and would require very quick replacements. I was also curious about my multipart line idea, and since I'm cheap and don't want to use blocks the friction on the haulback might be excessive. Then i was wondering how i was going to do the guy lines, chain is kinda standard on smaller gin poles like this, but that's honestly fairly expensive. I then decided to flip thru a book i had and it dawned on me that wire rope was used on ships gear, and simply cleated off like rope would be. So my guylines which wouldn't require me hauling in by hand could simply be done like that on a pipe bollard.
The running lines was still bothering me, then i realized 5/16 cable doubled has the same wll as 7/16 cable does on single. A 2 to 1 would pull just fine, but i still couldn't figure out how to run them by hand, until i figured i could just use a cheap 3 stand and make the running rigging into a wire core line, just like the old school fliplines. So that's gonna be my plan on those, I'll simply make a very long wire core 3 strand flipline, and I'll be able to haul it back, run it on a bollard, cleat it, and lower it all by hand without finding every little meathook on it. The rope will eventually degrade and start tearing, which at that point i can just replace the rope part, the strength is in the wire anyways. If you guessed the bollards would be made from pipe, you are correct I'm thinking 4 inch like the blocks are, with a 4 inch pipe saddled across the end for nice large radius cleat. I'll calculate loads for the guylines today, and double check my gin poles are sized correctly.
I'm waiting for the rain to quit, but i was able to double check all of the loadings and make sure what i wanted to use for everything. I'm not going to bore everyone with a bunch of trig, but with the geometry i randomly chose the guylines will be the same size as the winch line, which is 7/16 wire core. The guyline in the back will doubled so it's in the wll, so that will make ordering wire easy. So gotta hunt down a wire supplier close, I've used lifting gear hire (actually the name of the company) before so I'll call them Monday. I might need to call an old employer to use them as the delivery spot (forklift and industrial spot for a semi), so I'll have to do that too.
I'm thinking of doing 7 x 36 wire for the flexibility, wire core for crush resistance. I'm not planning on abrasion being too bad, but we'll see. I also had a moment of clarity and decided to use some 1/2 wire spliced into grommets for all the tension connections on the poles, so i grabbed some wire at tsc for that. I like that idea better than welding the truck axle up, and it will be more than strong enough. I'll do them with a 4" pipe welded to the outside of the 3" for a better bend radius, with little clips to keep everything in place since it will be up in the air. I also grabbed a bunch of hitch pins to lock the poles in place on their supports. I could have made some from rebar or something, but the drilled holes with pins, galvanized finish, and the fact they were less than 5 bucks a piece almost makes the decision for you lol.
The 2 inch pipe isn't in any column loading charts i can find, but it is very commonly used as the larger size for 1 ton truck mounted ones, with similar length and winch size, and will lift the front end up on those trucks. Further if i consult the charts, 3" pipe is rated for 14k pounds at 15 foot, and the shearleg design using 2 inch will hold at least that by estimating from the sizes bigger. I could do the calculations, but I'm pretty confident I'm good there. The slenderness ratio is 69, so I'm still good there (at 120 you switch formulas because of a different failure mode). The 2 inch pipe up top acting as a pin will be a beam, but it's so short i think I'm good there. The base supports will be likely the lowest strength member on the whole thing, simply because they are nothing but 2 inch pipe sticking out from a 3 inch pipe, with no supports. The welds on those will be the most critical because that's all that will be holding it on and it's a tearing force, which is about the worst you can do. They will only be 6" long tho, and loaded 1.5 inches from the welds, so honestly I'm very confident there too. So from my shoddy math, this should work just fine. Here's a picture of the column loading chart, from the Bible of building anything, aka machinery handbook. If you do dumb stuff like using scrap and welding rod, it's an excellent resource, as is engineering toolbox online. It even has sections to walk you through the math (if you ever need to do math and not simply read a chart), which is helpful because if you don't do it everyday you forget.
Even though your descriptions have been very good, I only have the barest grasp of what you're doing. Looking forward to the finished product, and I reverse the process from that. Easier to wrap my head around it.
Pictures will help as it comes together. Thinking these details out before you try to do them really helps cut down on mistakes. I spend way more time designing stuff than building it usually. Arguably it's the most important step
Turned out to be beautiful day! Quick and dirty miter for a bit better fit. I'll actually have to layout and torch the 4 on 4 saddles for the guylines. Going to use up some i beam drops to mount them on the back too. Need to do a beer run pretty soon too lol
So yeah, that worked pretty well. You tend to forget how much 3 strand will actually stretch under load, but when we took it off the trailer at the new spot we used hard rigging and the thing was rock solid. Used a couple of 1 ton chain falls almost to max capacity (you literally can feel how much load you have on them) and the thing didn't even move. I can't wait to finish the rest of it. And yes I'm aware my finger is in the first picture. At least it's not a drawing
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