truss boom design

[ironman1952]

Thanks for all the great comments.
I basically have plagiarized the approximate length of the boom with what the main manufacturers have engineered and are already selling with what the weight limits that are from fully contracted to fully extended.
I am still working on the materials I will use. I would like to use a rectangular box beam that is about 3X6 for the largest size. Putting the 6", outer tube vertically.
I have been talking with one of the guys at a local steel vendor and he said getting the inner piece to not be sloppy is the issue. I was thinking with 1/4" wall tube I could drill and tap lets say 1/2" bolts on all 4 sides, strategically placed to adjust the slop out of it.

I still can decide If I should build to go over pallet forks or purchase a 1/2" quick attach plate, they are only about $180

I also am going to put the boom at about 18 degrees to the plate or forks.

A work in progress

 

[BlueKnife]

Thanks for all the great comments.
I basically have plagiarized the approximate length of the boom with what the main manufacturers have engineered and are already selling with what the weight limits that are from fully contracted to fully extended.
I am still working on the materials I will use. I would like to use a rectangular box beam that is about 3X6 for the largest size. Putting the 6", outer tube vertically.
I have been talking with one of the guys at a local steel vendor and he said getting the inner piece to not be sloppy is the issue. I was thinking with 1/4" wall tube I could drill and tap lets say 1/2" bolts on all 4 sides, strategically placed to adjust the slop out of it.

I still can decide If I should build to go over pallet forks or purchase a 1/2" quick attach plate, they are only about $180

I also am going to put the boom at about 18 degrees to the plate or forks.

A work in progress

I would definitely go QA mount. It's gonna be a lot less sloppy and more secure. I would also make the boom come up off the mount at a much steeper angle. Gives better lift angles, IMO. I've got the materials sitting outside to build mine, just haven't got around to it yet.

 

[BlueKnife]

I'm not seeing much of a truss design in your drawing, unless I'm missing something.

The name comes from what they're designed to lift, not how it's built.

 

[MTGreen]

Adding some blocks and strap to the top of your boom greatly increases strength like the boom on this cherry picker:

https://www.google.comhttps//www.google.com/imgres?imgurl=https%3A%2F%2Fwww.ruralking.com%2F_next%2Fimage%3Furl%3Dhttps%253A%252F%252Fd2dz5gposoi2o6.cloudfront.net%252Fecom%252Fprod%252Fitem_images%252F0%252Fd%252Ff%252F2%252F0df276cbf796bc8e21aa910deea034efc159d0cf_57100060.jpg%26w%3D1080%26q%3D75&tbnid=DDwzvJyC6MZKxM&vet=1&imgrefurl=https%3A%2F%2Fwww.ruralking.com%2Fbig-red-2-ton-engine-hoist-t320011&docid=K8X4abbAffkZlM&w=1001&h=1000&hl=en-US&source=sh%2Fx%2Fim%2Fm6%2F4

 

[BlueKnife]

Thanks for all the great comments.
I basically have plagiarized the approximate length of the boom with what the main manufacturers have engineered and are already selling with what the weight limits that are from fully contracted to fully extended.
I am still working on the materials I will use. I would like to use a rectangular box beam that is about 3X6 for the largest size. Putting the 6", outer tube vertically.
I have been talking with one of the guys at a local steel vendor and he said getting the inner piece to not be sloppy is the issue. I was thinking with 1/4" wall tube I could drill and tap lets say 1/2" bolts on all 4 sides, strategically placed to adjust the slop out of it.

I still can decide If I should build to go over pallet forks or purchase a 1/2" quick attach plate, they are only about $180

I also am going to put the boom at about 18 degrees to the plate or forks.

A work in progress

Also, I don't think you want the inside boom to be bearing on bolts. Should be bearing on a flat surface. What I'm going to do with mine to take up the slop is to make a bearing surface on the ends of the interior and exterior tubes to change the dimensions on the ends slightly. Basically just weld together a square out of 1/2"x1 1/2" flat stock that's closeler to the size tube that it's fitting. Weld that to the end of the machine end of the interior tube and another to the hook end of the main tube. There will need to be a groove in the interior one to swallow the weld seam on the main tube. Hope that makes sense. Maybe I'll try to draw it up later so you can see what I'm talking about.

 

[5030]

When I set my assembled grain tanks, I borrowed a buddy's big JD FWA tractor with an FEL on it and strapped on a telephone pole and set them with that. Problem was, unhooking it from the top of the grain bins.

 

[Streetcar]

What thickness Tube wall are you using. You are making a boom pole and forces are rather simple to determine

 

[ironman1952]

Still in research mode thought about .25 wall thickness on outer tube or maybe .375
Still have to find the right vendor to purchase the materials.
Farwest only sells full 2' lengths.

The idea of welding on a spacer to the outside of the interior tube makes all the sense in the world.
Thats why in the multitude of counselors there is success !

 

[CliffordK]

Why not just rent one of these ? I bought one to service my windmills, trees & gutters, but for just a short time, rent one and see if you really need that capability all the time. I can take the bucket off and put on a homemade jib crane arm, all controlled from the ground. View attachment 846205

I've thought about using a boom lift as a crane or telehandler. Every once in a while a used one shows up pretty cheap. However, they are often limited to 500 or 1000 lbs lifting. Probably OK for lifting wood, but it could be problematic for steel. It isn't clear how easy it is to move the controls from the bucket to the body, or perhaps many have dual controls already.

Someone mentioned removing the truss or load. One could design a method that attaches that can be released from the ground. For example using a rope that goes from the end of the boom, through the load, then back to a pulley, and back down to the ground. So, simply release the rope from the ground and pull it through.

 

[CliffordK]

Farwest only sells full 2' lengths.

I think you missed a digit. 20' to 24' for full lengths. Many other vendors will cut to length. I think your diagram is showing about 18 feet, so you're pretty close. Do you have a fairly longer trailer to haul it? I usually load a stick of steel forward most of the length of the tongue nearly to the hitch. Keep it narrow and you will be able to turn fine. Tie it down and toss a flag on the rear.

If you bought something like 2" x 5" or 2" x 6" steel tubing or whatever would slide onto your fork flat, you would have a pretty sweet fork extension. However, at 20 feet you'd get a bit of flex.

You'd probably do better with say a short piece of rectangular steel tubing that would slide onto the fork, then weld a long piece of vertical I-Beam onto it. Say 3"x6" I-Beam for the extension.

You'd still get a fair amount of weight sticking out 20 feet in front of the tractor, and may benefit from trying to keep a lightweight design.