I bought it off of YYG, and emailed YYG, and they gave me no help with this. What is the size of the axle in the Energy By Barco Yoyos?
You could go to a hardware store such as Ace and they will have a size chart that will allow you to find its size.
I went to Home Depot because it was close and they didn’t have any set screws longer than like 1/4 inch. If you or your dad has even some small bolt cutters (or even wire strippers like this that have a small bolt cutter thing on it that works very very well) then find a bolt of the right size (might be U.S. size, might be metric, just make sure it fits perfectly and the next size up doesn’t fit better) and cut the head off of it.
EDIT: I forgot the / on the /url 
Home Depot won’t have anything you need. ANY ace Hardware will. I buy from them all the time. They can find the right one for you too.
Ok THanks guys! Ihave an ace hardware near me… so i’ll check that out 