Here is todays hardware project for the Panasonic GM1:
DIY Adapterholder for FOTGA Micro 4/3 to Nikon F

Steps

First cut the 54mm hole into the 1/2" plastic board:

The plate is put into a rotary table to mill the outside:

The lower bracket is squared and cut to size:

The Slots are milled at a 45° angle:

The 1/2" slot is milled to hold the upper plate:

Cut one side to allow the holder to tighten the adapter:

Drilled the 3.5mm hole for the M5 tap: