part 6 finally!
https://www.youtube.com/watch?v=WRRt7qvW4Ng
WrenchLife
I got that drive from a guy in England called
ronsbits.co.uk, it is about £130? but its quite a chunky unit, I've seen other mowers with smaller ones. for a mower what will also work is a 'right angle gearbox, (RAGB for short), If you are in the US i would suggest looking in a tractor supply type shop, its a small industrial gearbox, so they find all kinds of uses and you can probably find a smaller one for cheaper. happy building!