Dual Bearing Filament guide

thingiverse

UPDATE: BE AWARE that I have confirmed that this design can cause enough variable tension to result in horizontal banding issues where the extruder is on the X-axis. It shouldn't be a problem for a Bowden setup. This is a dual bearing filament guide designed for use on a 2040 extrusion, similar to an AM8 model. I prefer having the filament feed off the bottom just past the center of the spool. This way, if it gets stuck, the roll will pull straight down. If the feed is off the front, stuck filament can/will pull the spool off and onto the printer bed. The rear bearing helps make this a smooth pull. I had tried a simple ring previously, but although it worked, I wasn't happy with the drag on the filament. To be honest, the front bearing probably isn't necessary, but it didn't hurt and I had extras waiting to be used. This design is intended for use with Deno's spool holder (https://www.thingiverse.com/thing:2537713). The bearings are 608 Bearings, which are exactly the same ones used in Deno's spool holder. You can buy 16 on Amazon for about the same price as 4, so I had extras. I have included holes big enough to put M3 Bolts through the caps and guide body, but so far the snug fit with the bearings has been enough to hold them in place. The bars from the main guide to the cover seem to be somewhat fragile using the roll of PLA I currently have installed. However, I've had no problems with breakage using PLA+. You may want to make sure the fit isn't too tight before final assembly. Let me know if you experience any issues with breaking, and I'll consider a redesign. I made the bottom 2040 frame clip longer than normal so it requires some force to get it snapped into place. This was done intentionally since tangled filament will try to pull up the back of the guide. I've also included the original Sketchup file in case you want to make any modifications.