Some type of flex joint is nee. ... Each of these joints contains some material for movement and inserts may consist of rubber, urethane, or steel spherical joints, depending on application.

There’s a paper describing this spherical gear as part of an active ball joint mechanism and even if you aren’t mechanically inclined, it is something to see.

One of the many advancements brought about by 3D printing is the rapid development of compliant mechanisms and flexure joints. One such example is [jicerr]’s joystick, which uses a pair of sp… ...