What ist?

He says they're twisted because it works at 90 degrees, connected to the bevelled gearbox, or something. Or maybe a spiral bevel gear, he's just said (he's been googling all evening, liking an engineering conundrum).

Likewise PP! Just it bugs the excrement out of me when I can't find anything similar.I understand the principle of a crown wheel, pinion and planet gears but can't figure how this would equate?

I still fancy its a double ended key for something that needs a spanner on the large central nut to turn it, but still can't understand the twist? I don't think its been forged, more likely to be a cast steel lump methinks.

Where's Fred Dibner when you need him?