Ball joints on a motorcycle?

I didn't like the way the frame tubes were just open behind where the shocks mounted and wanted to weld some sort of spike or something on there. An internet search didn't come up with the kind of spike I wanted but while messing around with my race car stuff, I spotted these ball joints from a 1967 MGB-GT. There are polished balls of steel and slid right into the frame tube, so I just welded them on.