I created this bracket as I needed a way to secure the AtomRC FPV Gimbal (Linked below) to my Volantex Phoenix, though it would work to attach the base to any model that has a flat surface under the mounting platform.

I printed mine in PETG for strength but pretty sure it would work just fine in PLA. 

Uses m3x5x4 heat set inserts.

Gimbal: https://atomrc.com/products/atomrc-high-resolution-3d-print-wide-angle-range-gimbal-for-fpv-airplane-fixed-wing?variant=40218642317445&_pos=1&_sid=d08153fb8&_ss=r