I don’t know if this will help anyone,
but i just thought I’d throw it out there for anyone who thinks their yoyo has a lil vibe.
Items needed:-
A BvM/PEAK/Bape/Dif ect…
PTFE tape.
A hex/Allen key to fit the axle.
Scissors
Take your axle out and wrap the last 6-7mm with loads of PTFE tape, at least 6-7 times
Then trim off the excess tape hanging off the end. (if needed)
Use enough so you can not turn it without the hex key
(i’ve used loads and i’ve never done anything to the threading)
Stick the axle in the same side the bearing tends to stay in PTFE end first, twist it until it stops.
(remember its got lots of PTFE tape on it so it might only go in 2 turns)
You will then have a “non bearing half” and a “bearing half” (with bearing and the axle in it)
Put it together slowly.
When the non bearing half hits the end of it’s thread, it will start to screw the axle into the bearing half.
Close the yoyo tight.
(sometimes the tape will move up the axle and not go into the yoyo threading, if this happens just try again, after a few times of you’ll start to coat the inside with PTFE and it will start getting stiffer, but remember it needs to be really stiff or the axle will move over time)
Then open it again, spin the non bearing half off so you don’t move the axle.
Now, get the hex key and stick it in the top of the axle, hold the yoyo up with the hex key pointing upwards (like you’re looking at a clock).
Turn the hex key clock wise, counting how many rotations you get, until the axle end hits the other end of the thread.
Say (for example) you get 2 and a half turns before the stop.
now, wind the hex key back anticlockwise half the number you counted, (in this case one and a quarter times)
Put it together again, you now should have a perfectly centered and secured axle, and hopefully a smoother yoyo 
If there still a small vibe you might need to turn it one way or another a little bit to find that “sweet spot”,
start with a quarter turn one way, see if its better than before.
If its not you’ll need to turn it the other way and try again, eventually you’ll find that spot where its smooth, and if you used enough tape/locktite it should be stiff and won’t move when you unscrew the yoyo
EDIT:
You can also use locktight.
let it dry, crack the axle open with the hexkey and then tune it the same way when its stiff and tight ^^
(this way works better tbh^^)