A remixed variation of the Rochat-style flywheel for the Open Press Project, originally by user “dddddyck” on Thingiverse - ( https://www.thingiverse.com/thing:4797673 ).
I have rebuilt the wheel to add a handle - you will need one 20mm long countersunk M5 machine screw to install (the threads will cut themselves into the handle piece, connecting them securely).
No supports are needed for either part, I'd suggest 3 walls for strength and an infill of 20%.
The original (and brilliant) Open Press Project can be found here - https://openpressproject.com/ - which includes links and instructions for building the main press.
The author remixed this model.