# Fixing a Rotring 800 Mechanical Pencil. While getting his Mechanical Engineering degree, my younger son splurged on a Rotring 800 mechanical pencil. They're about $40, but he was planning on having it as a long-term reminder of his work at school. While it's a very nice pencil, it does have one fatal flaw: If you accidentally drop it while the tip is exposed, it's weighted such that the tip will hit the ground first. Once that happens, there's a small plastic tab deep inside the pencil that snaps off, and the pencil is effectively worthless at that point. And, of course, that's what ended up happening with his. ![[rotring 800 pencil tab.png]] ↑ Screenshot from Francisco Yerena's [video](https://www.youtube.com/watch?v=KwP-M4c3PH4) showing his broken plastic tab It's not obvious how to open the pencil to repair it, but thanks to a [YouTube video](https://www.youtube.com/watch?v=KwP-M4c3PH4) from Francisco Yerena, I was able to disassemble it completely and get access to the tab. My first attempt was to superglue the tab back together, but that failed pretty quickly. I also couldn't find a replacement for the inner assembly (nor just the white plastic section) for sale anywhere. I ended up modeling a replacement bit using Tinkercad, and after several iterations got something that worked. I installed one in his pencil, and printed six more in case he needs one in the future. (Dumb lessons learned: No, you can't make it thicker, because it needs to slide within other things. No, you can't make the end solid, because otherwise the lead doesn't go through it.) ![[rotring 800 pencil fix.png]] The design is for the Rotring 800 mechanical pencil, but I'm anticipating it would work for the Rotring 800+ as well. You can access the Tinkercad project and STL [here](https://www.tinkercad.com/things/6AKCK55MSyp-rotring-800-mechanical-pencil-fix) ∎