Summary

I designed these for a robot project (https://hackaday.io/project/20153-robot-7-undefinable-wheeledlegged-dev-platform). They fit the linear actuators common on eBay and similar. They may be useful to someone...

They fit a 70mm hole (I have a hole-saw this size), secured with 6 screws or bolts. The bottom collar takes a 47mm OD bearing up to ~20mm thickness. I used an old headstock bearing from my motorbike that has an ID of ~20mm, enough to take the bottom mount of the actuator. There are slots for M4 nuts, allowing M4 screws to snug-up against the body of the actuator.

The pitch-roll head is a bracket for standard size servos that push-fits on to the shaft of the actuator (20mm) allowing a platform to be kept level (or not!).

See https://droidbot07.blogspot.com/2018/03/head-pitch-roll-and-yaw-mechanism.html for more.