Extruder ruler V2

**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