Parametric Scribing Pen Holder Ring

holds pen perpendicular to a surface and allows scribing an edge of a thing at a given distance.

default sized to fit Expo Vis-a-Vis fine point wet erase marker.

How to size for your pen/marker:

pen_tip_h how long the business end of the marker is before reaching the body of the pen

pen_collar_h the length of the tapered part of the pen body nearest the tip you want to interface with.

pen_collar_d1 the diameter of the pen at the bottom (narrowest) part of the tapered body end.

pen_collar_d2 the diameter of the pen at the top (widest) part of the tapered body end

pen_d the diameter of the pen at the widest point

scribe_r the distance from the edge you want to scribe