Engineering question

If you take a 6" diameter pipe and it is welded to a 24"x24"x1/2" plate, and is secured to a concrete slab. The other end will be secured to the large overhead ibeam trusses. The 6" pipe is 17 ft from end to end, and there is another pipe 3’ long that just barely slides over the 6" with an ibeam welded to the top of the 3’ piece and has a diagonal support from the bottom of the 3’ pipe up to the bottom of the ibeam. The 3’ long pipe will be about 2 to 3 feet from the top of the 6". The ibeam will be able to swivel a full 360 degrees, so it will only be 11.5’ long. My question is what size ibeam to use and what is the maximum weight I would be able to lift using a chain hoist at the end of the beam?

Shit, man, draw a diagram.

I can’t even begin to picture that baroque contraption. But even if I could, the question could not be answered without knowing the materials used, and what their tensile/compressive/bending/shear strengths are.

You are doing this backwards. The first thing to do is to determine the load you need to lift and then design your apparatus to meet that requirement.

Also expect the 3 ft long pipe to bind when loaded, and thus be unable to swivel around when supporting the load.

From the description, I think the OP is trying to build something like this boom, but with the ability to rotate the boom about the vertical support.

Unless you can do the calculations to design one of these (and if you could you wouldn’t be asking here), you are probably better off buying a prefabricated boom. Or pay an engineer to design one. Especially one as large as you want.

Edit: Here is another exampleof what the OP may want.

I’m maybe picturing it? A vertical steel 6" pipe secured to the floor and ceiling, with another, 3’ long, 6" inside diameter, pipe sliding over it, and a horizontal boom attached to the sliding pipe?

I just don’t see what’s supporting the 3’ pipe – why won’t it slide down to the base of the vertical pipe so it’s resting on the floor (or, more precisely, the plate on the floor that’s supporting the 6" pipe)?
At any rate, I agree that

  1. There’s not nearly enough info about the materials for even a good engineer to say anything about weight limits;
  2. A good engineer could give you a lot better advice if they knew more, including what you were planning on lifting;
  3. If you’re lifting things heavy enough to require I-beams and chain hoists, you might want to consider NOT using some homemade kludge and safety calculations from anonymous internet idiots.

You’re describing a jib crane or boom as mentioned above. Also, as mentioned above, there’s not nearly enough information.

Other info required: How thick is the floor slab? How is the base plate to be anchored to the floor? What is the wall thickness of the pipe? What grade of steel is the base plate, pipe, I beam? You really need to identify the maximum load you need to lift and work from there.

If the pipe, plate and beam are existing materials you have on hand, you’ll need to take precise measurements of the steel and bring them to an engineer. Use calipers to measure material thicknesses, measuring tapes are too imprecise.

God this reminds me of an Engineering Graphics 101 assignment. Don’t miss those memories.

This is not an engineering question, its a botch it together question.