u/Large_Meeting_7895

I am designing the gripper part of a robot I am building. I 3D printed my second prototype with changes to the hole size and mechanical linkage. I am using 6-32 * 1 screws. When tightened, they restrict gear movement and my servo is not strong enough to rotate them. However, when they are too loose, the hex nuts fall off and it looses structural stability. I have not mounted the servo onto the gripper, so I have to hold the servo in place while testing (I created a housing unit that is a near perfect fit so I don't foresee many problems after mounting). The hole size is fairly precise with a very small amount of tolerance, so I believe the problem is with my screw choice. Do y'all have any suggestions for a replacement or change I could make that would allow the gears to rotate freely whilst maintaining its structural stability and not unscrewing itself.