Drive mechanism for stepper extruder with Bowden extruder attached

This is a lasercut design for an extruder mechanism. The left 3 parts are cut in 6mm acrylic, the part on the right in 3mm but can be any thickness.
This design makes it possible to get the filament out without having to cut it. The Bowden extruder is attached by making a small incision in the PTFE tube and putting a 5mm washer (cut open) around it.

It made quite a few miles already and works very nice. The bolt makes it possible to adjust the distance between the bearing (8mm inside, 22 out