Pedal mounts
While I still have no clue when I might find the time to do the wood work (next to full time job, baby and the unicycle group I train), the metal parts already look fine (disregarding painting).
I used 9/16"-20 UNF to 1/2"-20 UNF adapters, 1/2"-20 nuts, big washers and two laser cut steel plates, 3 mm each. The one with the slot locks the adapter against twisting.
