RJ asked in Science & MathematicsEngineering · 9 years ago

Mechanical-Logic I am building a JIB Crane. Want to build 2 in 1.?


I am building a JIB Crane.

Want to build 2 in 1. Two lengths.

One 2600 mm, then remove a section and make it 700 mm shorter.

The structure is rectangular aluminum. If I cut the rectangle, what would it take to reconnect it with the same or better strength qualities?

1 Answer

  • Ben
    Lv 7
    9 years ago
    Favorite Answer

    Edit, I misread your question.

    You did not give the size of the rectangular aluminum tubing, or the wall thickness.

    Without knowing those dimensions I would use a piece of 1/2 inch/ 12.7 mm plate aluminum to cap the two pieces of rectangular aluminum tubing, where the removable section will be.

    Those caps/ plates will need to be welded to the ends of the rectangular aluminum tubing.

    One cap on the 1900 mm tube and one cap on the 700 mm tube.

    If the total length of your JIB is critical, you will need to shorten the JIB sections by twice the plate thickness.

    That would be 2 X 12.7 mm = 25.4 mm

    Make those plates about 101.6 mm bigger than the rectangular aluminum tubing dimensions.

    Example the rectangular aluminum tubing dimensions are 2 inch/ 50.8 mm by 6 inches/ 152.4 mm

    The 1/2 inch/ 12.7 mm plate aluminum caps would be cut to 6 inches/ 152.4 mm by 10 inches/ 254 mm.

    Use 12 mm bolts and washers to connect the two sections together.

    Space the bolt holes about 50 mm apart and 22 mm in from the edges of the plate.

    For my example tube size / 50.8 mm by 152.4 mm / that would give you three bolts across the top and bottom, and five bolts vertically.

    This image is close to what I described above.


    That image shows one of the two caps/ plates welded to a rectangular tube.

    Sorry if I made mistakes on the Metric stuff, I usually deal in inches.

    Again, If this is not the answer you were looking for, email me.


    Original answer

    You will need two frames with ears that overlap and pins to make the mechanical connection.

    Here are two images that explain:

    One this image, part number 8 can be welded to one side.


    This image shows the two jib sections being connected:


    The jib extensions that I am familiar with are lattice boom types.

    If this is not the answer you were looking for, email me.


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