Any quality instrument oil should be a light viscosity & not gum up or leave any residue over time. I got a free 8oz can of Microil instrument oil the last time I ordered AreoKroil so it's should last me a lifetime.
I recently got a gal of Velocite #6 spindle oil that I use for something else. I noticed the Microil is a lighter oil than the #6. I was thinking to use the Velocite as an alternative to 3n1 oil (which I don't use) for small bearings & misc stuff.
For an instrument oil, do you think Velocite #10 is too thick?
But if I had #10 I would try it along with any other light oil that does not gum up over time. I think it would be fine.
I will try some #10 and Kerosene and see how it goes. Doing some research on a tractor forum, it seems like it will not gum up over time. I'll try it in a micrometer and see how it works, and if it doesn't go well I'll report back.
Can bad oil in a micrometer cause false readings?