This is a slightly altered version of lasernipples' pencil holder. It still has the attachment the same, as it fits perfectly into lawsy's extruder for the solidoodle 3 (http://www.thingiverse.com/thing:47561) but I've stretched the hole so it holds a sharpie. There are two files. The first one holds the end part of a sharpie, and the other holds the main body, in case you need more reach. Between the two of them, they also hold a lot of common pens. A little set screw might well allow other sizes of pen to be added pretty easily too. These come out as non manifold, as I've not prettified up all the faces, but they seem to slice ok for me. I've printed both out. See 'instructions' for more details. All these print fine with no support. I use ABS. I printed these with a view to using my solidoodle as a plotter. This opens up a whole new wealth of possibilities. You can use multiple coloured pens and overdraw images, or turn complex pictures into vector drawings. I plan on using this to plot PCB designs directly onto photosensitive board avoiding the need to print out on pricey transparancies.