2020 extrusion tapping guide

I have just started to build a Core-XY printer (http://www.thingiverse.com/thing:1003119) and one of the jobs I need to do is tap a 6mm thread into the end of a number of the 2020 extrusion pieces. Tapping is an easy task - as long as the thread is started straight and true.

To help with this task I designed this little guide. Just slip it over the end of the extrusion and use the guide hole to keep the tap upright and on-centre.

It was designed in OpenSCAD: the source file has various