Spool holder replacement that self centers for Prusa Core One - full set of needed parts.

I really liked betonk's Spool holder project so I printed and deployed it....worked fine but I've got some old irregular spools that weren't working with it, particularly ones that were too wide for the plastic nut to reach in far enough for it to thread up with the plastic bolt so I had to make an extended one which triggered this remix.  Also I found that it rolls so freely that the spool often gets a bit ahead of itself and starts unloading filament off of it potentially creating a tangle. I solved the problem by making and placing a ball on the spool to hold the filament in so it doesn't escape the spool.  Ether print what I uploaded or just use a tennis ball. :-)  The mount works well with M3-12mm screws and nuts.  I live in the US so I ended up using 5/16 size bolts to make the main shaft both connected to each other with a long nut and another regular one wrench tightened together to make a surdy base for the end bolt to screw into nicely.  On that shaft held in place by the mount piece are 3 1/4" washers, a standard bearing, a regular 5/16" nut, and then the long nut.  I could then put the plastic bolt piece on, deploy it's bearing (snug but goes in there with tightening. I then could losen back until it spins nicely and I'm good to go.  Incidentally the irregular spools I'm trying to use have holes that are less than a millimeter smaller than the plastic nut pieces so I end up reaming them out a bit to make them fit.  (I'll be so glad when I've used all of those up. :-) )  I provided my two additional stl files plus the original three made by betonk :-)