Animatronic neck - small, for MG90 servos

thingiverse

These are parts to make a small animatronic neck mechanism.They are made to work with MG90 servos, using 3mm shafts for the neck & head supports, with a 3mm i/d by 7mm o/d universal joint and 3mm i/d by 8mm o/d shaft collars - all readily available on ebay or amazon etc.The "neck block" is the lower half which the servos mount in to with a shaft through and protruding below for whatever rotation mechanism you add, the "head block" fits either on to or above the universal joint, depending how tall a neck you need and where the swivel point is.The 7mm one fits over the top of the UJ with an 8mm collar above, or the 8mm one fits separately to the UJ with jut a collar in it.See the photos for an example assembly. I used ball joint style rod ends and M2 brass threaded rod for the linkages. The ball ends are fitted with M2 screws, with m2 washers below to raise them clear of the surfaces and allow a greater range of movement.Set the link lengths so the head block is parallel to the top of the neck block with the servos mid position and arms fitted straight out each way.Use 3mm brass rod for the through shaft! I found that steel shaft is too hard for the UJ and collar grubscrews to bite in to - I ended up using penetrating threadlock to try and stop them slipping.There are holes for the various screws; they may need cleaning up to size. The UJ and collar positions can have longer screws fitted through some holes to lock the metal parts to the printed components.The thing in the overall view is a full size animatronic raven, a long-time project approaching completion - when I figure out how to add a reasonable feathered outer body!The raven skull I used is a scaled version of Menguy's excellent creation, here:https://www.thingiverse.com/thing:4963673That is so well made & detailed that the lower jaw can be easily detached by a few minutes work with a craft knife, then hinged back in to place!