Oldham type are great for this as their design allows for misalignment in the hubs, I would still do as Mike suggests though because something isn't right, the original couplings are rubbish though to be honest (no offence) unless everything is perfect, even then you can't really push them to hard, the forces can be to great really for such thin ali, they are designed for light weight machines really, 3D printers, engraving, machines like that.

For the price they pay for them I don't know why they even bother using this type on a machine.

.Me