This is a custom dowel lock bracket that I designed and created.

I made this for a custom phone extension pole / tripod, but it could be used for countless other things. It is designed as one universal part so you don't have a left or right half. Just print two or more of the same part as needed.

Watch a time lapse print here: https://youtu.be/Js5yqN42CuE

These brackets slide tightly onto a standard 7/16" dowel. They are infinitely stackable, only limited by the length of the screw holding them together. The brackets can be mated in any orientation at 45 degree increments.