For changes in the new version, see below.

Hi,
When using my Geeetech Prusa I3 pro B, my first 3d printer (I'm a rookie), I need to calibrate the extruder.
A usual way is to test and made adjustments mesuring 10cm + 1cm more.
For my own I made this gadget.
I put the ruler at the intrance of the extruder. I put the filament in the groove I have just to make the 10cm and 11cm mark on the filament.
I have added a 6cm position because, on my prusa, it is the good length for the filament to be straight when I change it. With 6cm mark, I'm sure that the filament is in the nozzle. And I can directly verify its straightness.
I like it because it is really a gadget but very easy to use.

New version: November 2017

Hi friends

Today, I modifed my Extrusion Ruler.
In this V2 version, I first duplicated the guide on the right side. It's easier for right-handed and left-handed people.
Then I added wrenches for M3 nuts and nozzles. Of course, do not use it on a hot nozzle but these two tools have been designed to hold the M3 nut or nozzle durig operations. Thus, you can use the M3 nut and the nozzle without risk of falling. For M3 wrench, a place is made for the screw during tightening.
No need of a high infill if you only use the ruler. If you want to use wrenches, I suggest you to use about 50% infill.

Bonjour chez vous.