Summary

I wanted a simple top mounted spool holder. seeing as the axle ones tend to fail after a while and I wanted something that didn't protrude out of the front much, and so this was conceived. Made it quite strong so it can probably handle even the bigger variety of spool.

Instructions

Print the left and right side holder, they are exactly the same but for a built in washer to space the bearings.
Use M8 threaded rod with nuts washers and bearings (I used 608 bearings, the same as in the Greg Wade extruder). Space the sides appropriately apart and simply place the spool on top.
I only used threaded rod on one side and bolts on the other to keep it lighter and simpler.
Suggest making the threaded long enough to accommodate the widest spool you could ever use just in case, made mine 200mm.
The bush has an inner diameter of 22mm and works great to line up the spool. Suggest using concentric as it is already a round object and it makes it look that much neater

Radial Spool Holder for Al Frame Prusa i3