1.75mm direct drive bowden extruder with tubing guide

this is an extruder designed for 11mm tooth gear, it has two variant, one with tubing guide witch have the space to insert a pece of ptfe tubing that guide the filament in the push-fit connector and one that does not have.
it is very good for soft and flexyble filaments and it is also extremely easy to assemble and load the filament.
the arm have also the tubing guide and connector.
the spring tension can be adjusted with a screw.
calculated step/mm = 92.59923 (but for error i have used 95