About this 3D model

Now you can sharpen your knives on the bottom of any old kitchen mug. The unglazed rim is highly abrasive, and this device allows you to make use of it without cutting your fingers off. I really liked the concept of benchapman's design, but figured I could make it more printer-friendly and adjustable. Here is an OpenSCAD version that is printed upright in order to avoid any need for support.