Are you talking about the connecting rod or the shaft to which the connecting rod counter-balance shaft is connected to? Or could it be the shaft to which the PTO shaft is attached?
New parts are just about impossible to come by. When restoring mine I took the last blades and rivets held in stock by two major MF agents. Can you post a photo of the damaged item? Is it repairable?
Are you in the UK? There are normally several MF 60's for sale on UK Ebay. However the prices may be too much to scrap one for what you need.
I've attached another photo of mine which was restored in 2011. I've tried to turn it but it has still come out wrong.
Please let me know which part is broken.
DavidP, South Wales