i use a vise....turn the clutch upside down, install the nut in the vise, tighten...either by hand or with some big channel locks, grab the outside rim of the pulley itself and twist..works very easy, alot easier than trying to fing a socket/wrench..mine is a 39mm.... the vise is easier....of course your vise needs good square jaws to hold the nut, otherwise itll pop back out when you try amd tighten.... and i use my feet to reinstall the spring/clutch then place back in vise to final tighten..takes about 7min all together.... art is correct about messing the nut up, wont take much to cross thread..be careful there.