Geeetech Filament Spool Adapter

I had ordered some GEEETECH filament and the spool centers were way too large for my Ender 3 printer. It made the filament pull very hard to turn the spool. I looked for an adapter to fill the hole. I found one by RoRo_Avocado. This was very nice and almost worked great. Two problems presented themselves. First my Ender 3 spool holder end was 2mm larger then the center hole in Mr. RoRo_Avocado's adapter. So, I remixed that part changing only the center hole by enlarging it 3mm, and it works perfect now. Second problem is that the adapter would fit very nicely and perfectly into one side of the spool, but would fall out of the other side. The spool center is not same on both sides. So I needed a way to hold the adapter in the center hole. I designed and printed these bolts and nuts to do just that. I did not want a large head sticking out at the ends to get caught on something so I made them with as flat of a head as possible. These screws should only be, and need only to b