"3 in 1" oil is nasty smelly revolting stuff.  I try not to use it at
all.  For most general lubrication I use automatic transmission fluid
[ATF] (the pink stuff) known in the UK either as TQF or TQ Dexron,
which appears stable, harmless and virtually odourless.  It also has
the great benefit of not breaking down easily under harsh conditions.

I've never tried lubricating any "difficult" motor bearings but all the
odd ones I have used it on (like the lawn mower) seem to be just fine.

There must be a tribologist (nice word :) in MMD who can tell us the
real story.

Jeffrey Borinsky