I don’t have any special tools to do this, so it took me an hour per cap to make.
Heres what a Loop 360 looks like from the factory, just in case you don’t know!
I used this plastic bowl.
And I cut it out as close as possible with a pair of metal snips, and then sanded them down until it was the perfect size, which took forever.
The cool thing is these feel better than the factory caps.
It’s hard to tell the caps are convex unless your actually holding the yoyo, but you can kinda tell here: