We originally made some heavy duty replacement spindles but, since they had to fit in the factory hubs, there was only so much we could do and they were still a weak(ish) link. So... we decided to start from scratch and offer a complete axle assembly.
Those axle assemblies were made from almost all custom pieces and were very strong. We started off with the YM3110 2wd axle design and modified the pieces to fit the smaller tractors (4 bolt hubs that fit the larger spindles, steering arms to fit larger spindles, etc). I think there are still a few of the individual components on the shelf at Hoye but I don't think they do the welding there anymore. You might try calling Braden (Hoye store manager). He might be able to sell you the individual pieces.
Aaron