Like was mentioned you really need to post a pic or two to help clarify. Are you speaking of the clutch disc? the 3 pin clutch driver? what welds are you speaking of? If you're talking about the clutch disc did it have an OEM laminated disc or one of those aftermarket specials of solid material?
I meant to put this in my post to Joe but CRS set in momentarily but it's about time with the grenade gears. That poor tractor has been carrying around that unneeded weight for 43-45 years now. Also, give us a report on how well the balance weight works. I have one but haven't installed it yet.
Hydro Harry, hurry up and re-assemble that motor, I'm curious also if you think there's any improvement in vibration.
I had limited experience with mine before I tore it apart. I find it a pain filled experience to operate as it sits now... the vibes actually numb my hands and feet!
Here is a pic of the broken plate that I replaced 3 weeks ago. The same part failed again yesterday. One of the roll pin lugs came apart from the plate. The welds are tiny. The one in the pic was from a Cub dealer and was installed in 2013.
CC Specialties (one of the banners above) has a replacement 3 pin clutch driver that is better than OEM IMO. I bought one last year for a customer and I was impressed with how much beefier it is. It's also cheaper than the replacement part.