I had some fully synthetic car gearbox oil left over from a car project – so I drained and filled the headstock on my Harrison L5 with that ! Definetly quieter than the bog standard gear oil used in there previously – and the main bearing runs cooler if ut’s running at high speed for a few hours.. (yes, I know it shouldn’t and I do have a new set of bearings – but not the spare time to change them . .).
I would recomend ‘adding’ a magnet somewhere as it’s very effective at removing metal particles from the oil . . .
WALLACE