This is a Quad Lock ball mount. Used with a ram mount type arm. use a m3 x 40mm hex cap screw and nut for more strength.

Update 2021-04-22: Split into 3 separate pieces for easier printing.

Robo 3D

R1 ABS + PLA Model

No

Yes

30%

I used 3 perimeters. With ABS, locking lever is flexible enough for easy on/off.