Prusa Mini Extruder skrew extension

Do get the tension right on the extruder. Filament need to be fed exactly the right amount. If it is not - the slicer settings do not matter. This little print will solve a lot of grief, and save filament. 

I did struggle, as many do, with getting a smooth print when using flex. Stringing and failed prints. One of the culprits it took time to understand was the extruder screw tension. Getting it perfect is a struggle already when trying to get the allenkey into the screw head. And then, when twisted, it drops out. 

I got myself a M3x53 screw and printed THIS extender. Pushed the screw into the printed extender, and the replaced the original M3x43 in the extruder. Voila! Now its a joy to print flex material (as long as the temp, speed, extrusion multipliers are right). Before adding this - smooth flex prints without stringing were beyond my reach. 

I used ASA and TPU. I think that any filament will do. 
Use the old spring and make sure the 1cm longer screw extends as much as the total of the original did. Do not forget the original spring. You might need to resize with +/-0.1mm depending on feed rate and filament used.