Well I use it when drafting my scratch built works and for sketching so yeah it's related. :D
Got some issues with my dioramas so I decided to take a couple of days off working on it. While cleaning my work place I found my small collection of mechanical pencils! What I'm currently using is a Rotring Tikky ii (first pen from the top) which served my purpose very well. Inspecting my pens I remembered that I have a Rotring Tikky that had issues. The lead keeps on jamming the pen tip. I then decided to check on it and fix it, I also realized that this is an excellent opportunity to try out my DIY Macro Lens!
You can visit The Old Geezer's blog site at onelonemanspensandpencils.blogspot.com some cool cool pens there and excellent reviews, makes me want to buy moar pens!
All clean and working, I am now a happy owner and user of Tikky and Tikky ii! Here are more pics of the two pens and a couple of detail pictures of the Tikky ii.