This question is more of a mechanical rather than 3d printing, but I am assuming 3d Printing communty have already come accross this issue, therefore this is a good place to ask.

I am building a simple RWD vehicle using 3d printer parts. See the picture below. RWD vehicle with steering

As you can see from the picture, I am using 3d printed linkages for steering mechanism and I used regular bolt and lock nuts to secure them together (thats what I had laying around the house at the moment). The problem here is that, holes in the linkages are not exactly the size of the bolt, and because the bolts are threaded, it generates a lot of friction. Other than that, the bolt seems to sit loose inside the hole and creates an unstable pivot. enter image description here

If I tighten the nut more, it just presses them together making it hard for the servo to operate. I am looking for a solution that will use simple bolts, nuts and washers which can be bought easily off the shelf (or even with the bolts and screws everyone has around there house). What can be done to make this joint stable in xy plane, rotating freely around the bolt, or whatever the connection could be. By the way, even though I used nylon lock nuts, it seems to loosen after couple of repetitive rotations.

Thanks for your help in advance and I hope ya'll have a great day.

  • $\begingroup$ If you're really in a bind, you could potentially use two nuts on a single bolt. The first bolt acts like the shoulder mentioned in tjb1's answer. Obviously, tjb1's answer is the best solution, but if you don't have the resources and you just need to get it done, this is a possible temporary solution. $\endgroup$
    – tbm0115
    Feb 20, 2017 at 23:17

1 Answer 1


A correct length shoulder screw would work great in this application. They have a shoulder that is held to a precise diameter and a length. You can thread a nut on and tighten it against the shoulder to prevent clamping your pieces. They may be hard to find locally in stores but are readily available at places like MSC, McMaster-Carr, and Bolt Depot.

enter image description here


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