Biggest secret to turning yo-yos that I found is to weigh the halves of the yo- yo. You need a scale with accuracy down to 1/10 of a gram. Profiles need to be similar, but not exact, which is hard to do. If you use the craft supply trans axle (ball bearing collar on the axle), the two inserts have different weights, so that needs to be taken into consideration. No finish on the inside surfaces of the halves.
robo hippy