Tru-oil is a polymerizing finish and therefore doesn't really lend itself to being applied under friction on the lathe. I wouldn't suggest doing that. I sand my calls to at least 600 and then apply it by hand with a piece of cotton t-shirt, rubbing in all directions to work it into the grain. Let that dry at least 2 or 3 hours, then buff with 0000 steel wool and re-apply. I'm usually using at least 3 coats.