This mount was designed to modify and adapt a nFD 50mm f/1.2, along with one of these parts:
Aperture Arm http://shpws.me/ShCi
Follow this link to see the tutorial:
https://youtu.be/Jiv1HAlwF68
Disclaimer: This mount and arm work for the regular nFD50mm f/1.2 NOT the aspherical version.