RE: Tri-Flow grease. Tri-Flow grease is a synthetic and because of that it doesn't melt, get soft and fling off of spinning gears like the softer grease Singer sells as motor lube.
Because of this it's not good to use in motors that use grease. These motors need a grease that will get soft and flow to the bearings as the motor gets hot.
I use only Singer motor lube (grease) or vaseline depending on what the owners manual says.
I use Tri-flow grease on gears.
Joe