I ordered 4 different color Hard Candy balltops from GroovyGameGear. They are 6mm. I have a U360 and when I tried to put them on they started to screw on and I couldnt get them more than 25% of the way on. When I look at the threads of the original ball and the Hard Candy balls they look the same but the Hard Candy ones almost look like they taper inwards as you look down the hole. I wanted to know if anyone has any idea on this? My plan was to get 4 J-stiks (same shaft as U360) and use the Hard Candy balls (need Red, Blue, Yellow, Green). If anyone has another idea on getting 4 switchable 4/8 way joys with those colored balls please let me know.