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DIY 3d printed ball swivel

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  • Sambista
    paranday, thanks. I'll look into that.

    dad, agreed, my shortcuts here are not ideal.

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  • paranday
    I believe the ARC has an acetal ball.

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  • dad
    Really interesting process, the only thing "I" would advise is never use a wood or drywall screw when you can use a machine screw. A machine screw with flat washer and a lock washer in "my opinion" is the best way to go. Also not a fan of a carabiner's.

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  • Sambista
    started a topic DIY 3d printed ball swivel

    DIY 3d printed ball swivel


    Having first punched a speed bag last week and with my shoulders not being in the best of health, I spent some indoor time over the weekend trying to make myself a ball swivel. I made this mainly as an exercise in design and prototyping - the process might be of interest, so here it is. This first post covers inception to the second working prototype (#7).

    It's certainly not intended to be a clone, but does bear obvious similarities in design and construction to the ARC which I've seen and read about. Ultimately, I will likely end up buying something (Thrasher EVO 13 has been mentioned twice to me), but nevertheless I thought there would be some mileage in having a go at making one for fun.

    I started with a few initial design constraints:
    • 25.4mm nylon ball (influenced by the ARC)
    • 69mm BCD bolt pattern seemed to be the "standard"
    • "as much of a swing" as possible (ball protruding as much as possible)
    • clearance around the mouth for the eye bolt, clip etc.
    I used OpenSCAD to come up with a design... first time I'd ever done roundovers, fillets and countersinks.

    Click image for larger version

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    I printed a few protoypes in PLA (using up old filament).

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    The nylon balls hadn't been delivered yet, so I used the time to iterate on the design looking at things such as:
    • dimensions: thickness, height, hole diameter
    • shape: support surfaces, strength, etc.
    • surface finish: printer settings
    Click image for larger version

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    I didn't like the wide, flat flange of #1-#3, so I made the fillet asymmetrical so it extended to the bolt holes to cover it a bit, and also modified the shape of the "mouth" to give the bolt a bit of support as it hits at the extent of the swing. Comparison of #1 and #5 below...

    Click image for larger version

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    Final (current) design in OpenSCAD looks like this:

    Click image for larger version

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    I had prototype #6 installed last night, and after one more print this morning to tighten up the tolerance around the ball socket, I currently have prototype #7 installed with a 4mm welded eye bolt (counterbored lock nut on the back side of the ball):

    Click image for larger version

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    It is a bit "sticky" in use... when it slows down, the ball judders in the socket. Weak drywall screws are NOT ideal to mount this with, nor is the use of a mini-alloy carabiner. But the way I hit, neither is likely to be a problem short-term.

    I might try a different ball (stainless finial ball??), a different filament in the printer, or perhaps I should quit now and just buy one.

    Hope that's interesting to someone.
    Matt. is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to and affiliated sites.