OpenSCAD syringe plunger

An OpenSCAD syringe plunger inspired by the excellent "13mm Flux syringe plunger" by Divinecobra (http://www.thingiverse.com/thing:1902471).

This parametric version allows you to easily change the plunger dimensions. Simply call :

plunger(PD=13.0, PBL=66.0, PCW = 2.0);

with the following parameters:
PD : Plunger diameter
PBL: Plunger body length (without plunger disc nor push/base disc)
PCW: Vertical walls width