An updated version that makes several improvements: Update 1: End stop screws widened to ensure E3D hot end fitment. Thanks to OzAdr1an for testing. Update 2: Bevelled edge body variant added thanks to 2n2r5. THis is to suit Printrbot hot ends or if you are having a hard time fitting your hot end. Update 3: Filament guide replaced with pre-prepared version from foofoodog, should now slice for everyone.Instructions correspond to pictures: Print parts at high infill for strength. No support is necessary. Accessory parts are optional. Choose between standard and bevelled edge body variant. Dimensions are in mm. Use a thin, sharp knife to remove the built in support from the body piece. It should come off fairly easily and leave behind a reasonably clean surface. The locking arm should be a snug fit and is held in place by a M3 x 10mm bolt. The ease in which the locking arm rotates is dictated by the tension of the M3 bolt. Move the bearing, washers and bolts over to the new tension arm. I prefer one washer at the front of the bearing and three at the back for better alignment. A M3 x 16mm bolt is a perfect length to secure the tension arm to the body. Use the original M3 bolts to secure the body to the carriage. At this stage is it a good idea to insert the hot end. Mine is super snug and wobble free just by closing the locking arm. Attach the extruder stepper motor to the assembly using more M3 bolts. The new filament guide piece (top piece) is modified to make it more compact and allow easier cleaning of the filament gear. On the left side a M3 x10mm or similar bolt is needed to secure it. At this stage it is a good idea to insert M3 bolt(s) underneath the body piece to hit the end stop(s). Happy printing!