I love the Open Brushless Gimbal by turbi but wanted a 3-axis version for my DJI inspired drone. I used turbi's files and changed most of the parts to this version.
I use 2208 motors and a storm32 BGC which works great for my GoPro Hero3.
The balls are from a standard DJI set. (DJI H3-3D Standard Version Part42 Damping Shock Absorber Ball)
The Bolts I used are stainless steel:
3x M3 x 20mm HEX button head (for the motor clamps)
1x M3 x 20mm HEX button head (for the arm1-arm2 connection)
4x M3 x 8mm HEX button head (for the motor arm3)
4x M3 x 6mm HEX flat head (for the GoPro case)
I added some additional snapshots of the assembly. I only use the 16 x 19 mm mounting holes of the motors. The housing of the motor is clamped in the different parts.
On request I also added the 123dx design file so you can build further on this design.
Short action video here: https://youtu.be/80s-3GhD2zk