About this 3D model
This is a pen holder designed for a Norland Research Calculator Controlled Robot: http://www.smallrobot.com/ It is sized to work with a standard full-size Crayola marker ~14.5mm diameter. There is a bridge between the clamp and the base which acts as a spring hinge to keep pen pressure consistent across bumps and dips. ~15 min print on MakerBot #322