A Better Ender 3 V3 Top Mount Spool Holder + Runout Sensor

Update: I've added files to relocate the filament runout sensor to the front of the spool. You'll need 30-40cm of wire, either a proper extension cable with the factory clip, or- like I did- some jumper cables for Arduinos, prototyping, etc. I recommend PETG for these parts as well, though if not using my 3MF be sure you turn OFF support on everything but the hole for the bolt on the main frame. I also recommend printing with adaptive layers for better threads, and/or .16 height. 3 walls on all the new stuff. NOTE: This will probably work fine on the Ender 3 V3, but I don't own the base model and can't guarantee it. Please share a make if you test it on the base Ender 3 V3. It will NOT work on the V3 KE or SE, and they already have top spools anyway! Background: I have 2 Ender 3 V3 Plus machines, and while the printers themselves work great, the original design for the spool mount and feed path is not great. Literally, within hours of using the machines I was thinking about ways to fix it. I've had these since June 2024, and for around 9 months did use the side spool, but routed the filament up and around, through a custom center mounted element. This wasn't the solution I wanted though, especially for TPU as the filament still partially went through a PTFE tube. A top mount spool design was included on the device from the factory, but I didn't like it very much- and the STL quality was not stellar. Design: With those considerations in mind, I created this! It's an improved design that can slide back and forth on the top of the frame. I included a slide-over filament guide which is not required, but recommended. Print Details: The 3MF file has manual supports painted on and 100% infill modifiers for a few areas. I strongly advise using this file. PETG, ABS, or ASA are highly encouraged. PLA would probably be 'fine', but it's not as ductile and could be much more difficult to remove once popped on. The filament guide would be fine in PLA. Once you've relocated your spool mount to the top, perhaps consider checking out my camera mount- it pops in place where the side spool used to live! 