Impossipuzzle

Never did solve this and 100% sure I never will so it's into the charity pile.

A couple of cubes came off in use (it can be quite stiff to turn) and I think I put them back in the right orientation.  That's not going to make the slightest difference to any mere mortal, and if it does get bought by a minor deity then a little extra challenge will just spice things up a bit...