I now use a 33 mm socket, with the recess on the end that grabs the nut turned off square, so it locates fully over the fork top nuts fully as well as being OK to use on the the oil drain, to tighten and undo these things. I use a piece of chammois leather with a hole about an inch in diamater cut in it, to go behind the oil drain when I unscrew or tighten it. This means that at last I don't leave circular tracks in the paint in the recess in the oil tank. The bit of leather came from my wife's going away outfit, dating from 1969
. We were all a lot younger then. And she still has her Tiger Cub!