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Wire Rope, Rigging, Snatch Blocks & Leverage ???

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  • Wire Rope, Rigging, Snatch Blocks & Leverage ???

    I'm in the process of helping a friend make a raising fixture for his crank up tower. It's a small tower, about 23' retracted or nested. The whole thing weighs about 800 Lbs.
    We muscled it into place and slid it over to the base and bolted the two ears to the base section. Now all we have to do is pull or tilt it up straight. There are several ways to do this.
    I've studied some raising fixtures, pretty simple but time consuming to make for a one time event.

    So I suggested he get one of those battery operated winches that people put on their pick up trucks or 4 wheelers. Some of them are rated at 2500 Lbs of pull. I don't think it's going to take anywhere near that amount of pull to tilt this thing up. When it was laying horizontal I was able to lift the top section a couple feet off the ground so he could put a couple 4 x 4's under it.
    I figured it weighed a couple hundred Lbs. at that end.

    So my question is if we were to hook the cable at about the 10' mark which is approx. the center point how much force or pull would it take to raise this?? I know there are a lot of factors involved her so if I missed anything please let me know.

    JL........................

  • #2
    If you could actually lift it at all when it was horizontal, then by lifting and then blocking or securing with cable/chain/rope at each new position (the "brute strength and ignorance" approach) you could probably have had it up by the time you posted this. You do have less weight to lift the closer to vertical it gets.
    "A machinist's (WHAP!) best friend (WHAP! WHAP!) is his hammer. (WHAP!)" - Fred Tanner, foreman, Lunenburg Foundry and Engineering machine shop, circa 1979

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    • #3
      if you could pick up one end by yourself, then little more than a gin pole should get it the rest of the way up.

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      • #4
        Originally posted by mickeyf View Post
        If you could actually lift it at all when it was horizontal, then by lifting and then blocking or securing with cable/chain/rope at each new position (the "brute strength and ignorance" approach) you could probably have had it up by the time you posted this. You do have less weight to lift the closer to vertical it gets.
        Yes I understand that. But we were planning on pulling it up with the cable attached to about the center of the tower, that increases the force needed to stand it up. I just want to know by about how much.

        He sent me this link with pics. These are easy to make but it's a lot of time and messing around for a one time deal. That's why I suggested the electric winch,

        https://www.google.com/search?q=towe...pexxE0GRzCBYTM

        JL.............
        Last edited by JoeLee; 07-11-2020, 12:50 PM.

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        • #5
          I put up a 70 foot tower that cranked up and put a cable on it a hooked to my truck and pulled it up
          Ed
          Agua Dulce, So.California
          1950 F1 street rod
          1949 F1 stock V8 flathead
          1948 F6 350 chevy/rest stock, no dump bed
          1953 chevy 3100 AD for 85 S10 frame have a 4BT cummins motor, NV4500
          1968 Baha Bug with 2.2 ecotec motor, king coil-overs,P/S

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          • #6
            Just what do you plan on attaching the winch itself to?
            Location: Saskatoon, Saskatchewan, Canada

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            • #7
              Originally posted by Ed ke6bnl View Post
              I put up a 70 foot tower that cranked up and put a cable on it a hooked to my truck and pulled it up
              That would be the way to go, however there is a chain link fence in the way and there isn't enough room to pull it up with the truck so my plan was to make a mount plate that goes into his hitch, mount the winch to that and pull it up.

              JL................

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              • #8
                Learn about force vectors and use some trig and start calculating.

                -D
                DZER

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                • #9
                  Originally posted by Doozer View Post
                  Learn about force vectors and use some trig and start calculating.

                  -D
                  I would like to, that's why I inquired here. I am hoping someone would discuss some ways of calculating such things.

                  JL.....................

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                  • #10
                    Originally posted by JoeLee View Post
                    That would be the way to go, however there is a chain link fence in the way and there isn't enough room to pull it up with the truck so my plan was to make a mount plate that goes into his hitch, mount the winch to that and pull it up.

                    JL................
                    I think Harbor Freight has those, called bumper hitch winch mounts

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                    • #11
                      Originally posted by nickel-city-fab View Post

                      I think Harbor Freight has those, called bumper hitch winch mounts
                      Yes they do. 2500 Lb capacity. That's the one we were looking at.

                      JL....

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                      • #12
                        You want to use a gin pole. It's common for raising sailboat masts. Guy wires to each side to keep it from tipping and one from where it rests to keep it from going over on you.

                        The length of the pole determines the force needed. If the pole is half the height of the tower, the force on the wire would be equal to or less than the weight of the tower itself (depending on where you mount the pole). So you could use a shorter pole and still be in the 1500 pound pull range.

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                        • #13
                          What is a crank up tower?

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                          • #14
                            Crank up tower have all the pieces telescope into each other and in my case I had to lift one section about 20 feet tall, then bolt in place and crank the sections up. Mine needed guide wires during the raising install.
                            Ed
                            Agua Dulce, So.California
                            1950 F1 street rod
                            1949 F1 stock V8 flathead
                            1948 F6 350 chevy/rest stock, no dump bed
                            1953 chevy 3100 AD for 85 S10 frame have a 4BT cummins motor, NV4500
                            1968 Baha Bug with 2.2 ecotec motor, king coil-overs,P/S

                            Comment


                            • #15
                              Originally posted by joelee View Post
                              that would be the way to go, however there is a chain link fence in the way and there isn't enough room to pull it up with the truck so my plan was to make a mount plate that goes into his hitch, mount the winch to that and pull it up.

                              Jl................
                              snatch block.....

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