Ender 3 Extruder Knob with Magnetic Top

thingiverse

There are many fantastic extruder knobs available, and I've had the opportunity to use several of them. However, I've encountered a couple of issues that have prompted me to create my own custom design. The primary concerns are: they tend to wear out and become loose over time, requiring removal for access to the extruder gear area, and I get tired of the design and want something new. To address these problems, I designed an extruder knob with a base that fits snugly onto the extruder shaft and a magnetically connected knob that can be easily removed when desired. This design allows for a secure connection while also providing easy access to the gear area and enabling simple replacement of the knob if I want a new look. The first component is the collar, which is designed to fit securely onto the 5mm extruder shaft without being too tight. I included a hole for an M3 bolt as a set screw to help hold it in place. This piece serves as the base and has a space at the top for an 8x3mm neodymium magnet. The second part is the knob itself, or knob-top, which is designed to fit onto the collar and features its own space for an 8x3mm neodymium magnet. The two magnets create a strong connection that keeps the top on securely while also allowing it to be easily removed when necessary. This design enables me to swap out the base and make new knobs as desired, giving me endless possibilities for customization. There are three STL files included in this design: 1. The Collar: This is the base piece that should be printed with 100% infill and a minimum layer height of 0.2mm to ensure strength for the set screw (M3 bolt). Before assembling the collar, pre-thread the set screw hole by inserting the bolt and threading it through so it tightens more easily when installing. The magnet should fit snugly, but you can add a drop of glue to ensure a tight hold if needed. Then, firmly press it onto the extruder shaft. When attaching, avoid over-tightening the screw if printed in PLA; instead, tighten just enough for a good solid fit. **7/30/19 Update:** I added collar v2, which features a slightly smaller set screw hole for a tighter fit and an extruded area to reduce material stripping and ensure a better hold. 2. My First Knob: This knob is approximately 48mm in diameter and boasts a simple design with a fairly large size. The magnet slot should be a snap-in fit, but you may want to add a drop of glue for extra security. Then, simply attach it to the collar, and you're ready to go! 3. Knob Center: This is just the top part that fits onto the collar. Use this as a foundation and create your own custom knob design! They love me, they really, really love me, don't they? If you enjoy my designs, please hit that like button and let me know! If you print my design, be sure to post a make so I can see how other makers' prints turn out and how they utilize them. If you find my design helpful or useful, consider leaving a tip to encourage me to create more content!