I designed this pulley so that i could have filament on the table beside my printer rather than on the top as originally designed.
It attaches to the frame with an M4 nut and bolt(i used M5 nuts as spacers as my bolt was too long) using a t-bolt bracket from: https://www.thingiverse.com/thing:2696207
but the 4mm hole in the bracket could be used to attach this anywhere.
The bearing in the middle is using this BB-bearing with a washer on either side, but a 608 bearing would fit too: https://www.thingiverse.com/thing:109261
-print 2 sides, then 1 hanger(with supports) along with however you intend to mount the pulley and the bearing
-assemble the pulley by gluing the 2 side pieces onto the outer edge of the pulley. I suggest superglue and quickly clamp all 3 pieces together
-put the pulley into the hangar with a small washer on either side of the bearing and loosely hold it together with an M4 bolt(at least 18mm)
-mount the pulley onto your frame using the t-bracket or however is best for you
-feed the filament through and into the hot end and you're away!
Higher the better, i used 50%. 3 perimeters/top+bottom