Very simples customizeable compass cutter. The tip holder was designed to fit both a pen or a sharp tip, to draw or cut papper, EVA and other kind of soft materials.

i was using with my hobby knife like this one: https://www.amazon.com/Farah-Hobby-Utility-Carbon-Blades/dp/B019CLD16W/ref=sr_1_7?ie=UTF8&qid=1469833301&sr=8-7&keywords=hobby+knife

To lock both knife and the position on the ruller, i attached m2 screws

The ruller is in centimeters