The ink from the marker liquifies with heat and friction, and lubricates the com better than cutting oil itself!
I like to use the marker on the armature too, where it contacts the bushings. In fact, I even use a sharpie on all my bearings in my chassis. I get a brand new one, and squeeze the tip untill the black ink falls into the bearings. Then it dries, and my car is lightning fast. It's messy, but a great speed secret.
I have friends that are machinists, and they all have those big Magnum markers in their tool pouches. They go through like 6 a day when they are working on the lathe.
You would think those CNC lathes would have a nice Magnum autofeed holder on them.
Maybe I should do a patent search...?