how to prevent lose thread in yoyo and axle?

loctight is not a glue it is a liquid that only hardens when the threads tighten up turning into a solid
the different grades are based on the amount that it expands during that process

Dropping your yo-yo will damage the thread the quickest.

If you don’t hit your yo-yo on hard surfaces often, you probably don’t even need Teflon tape or LockTite.

But to keep from unscrewing your yo-yo needlessly (in so doing, you run a higher risk of damaging the threads), use a toothpick to get the string out of the gap when you get a knot.

-Jacob

Necro poster. Seriously the problem was all ready solved.