Simple Bowden Herringbone Geared Extruder

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Edit: 1st April 2019: I have added V3 that allows better access to two of the stepper motor bolts that were blocked by the large gear in V2. It does change the ratio to 2.7:1 though instead of 4.25:1. Depends how much extra torque you need. Edit: 29th March 2019: I have added V2 that has 8mm clearance between the stepper and the extruder. This does make it difficult to access two of the stepper bolts due to different sized gears. This is a work in progress so I will update later with V3 when I have time. I also recommend putting a washer between the large gear and bearing to make sure the gear does not touch the bearing outer shell. I will try to add more pics later as well. I was looking for a simple geared extruder and also wanted to use the existing parts I had. Only 5 parts to print and I printed them all in under 5 hours. I designed them to mount either direction for left or right extruder. I have 2 mounted on my aluminium extrusion frame in opposite directions. I only have them held on with one bolt and have had no issues. Could easily add a right angle bracket if you like. This extruder uses a standard extruder that mounts to a stepper motor and adds gears. I have printed in PLA and ABS. Have used ABS a lot but only just now testing one made with PLA for durability. Have been using for some time and am very happy with how much better and consitent my extrusion is. My extruder now has a crazy amount of torque :) You will need the following parts. -Bowden Extruder I just used the cheap Mk8 left and right extruders as pictured. -2 x 508zz bearings -6 x M3 Nuts -6 x M3x8mm allen bolts -1 x M3x10mm allen bolt -2 x M3x25mm allen bolt -1 x M3x20mm alen bolt -1 x M5x45mm allen bolt (edit: changed to 45mm as I think its good to have a lock nut as this thing puts a lot of torque on the extruder gear and if the gear grub screw isn't perfect it can come loose.) I intentionally made some parts a tight fit so a little prep may be necessary to assemble. The gears and bearing bush you will need to run a 5mm drill through. I did this because I wanted it to be precise and not everyone will have there printer that dialed in. On the M5x45 Allen Bolt I ground down a flat spot on the head for the locking bolt on the large gear to screw up against. Also file a flat spot for the filament drive gear grub screw to screw up against! My Extruders were a perfect fit over the 508zz bearing and I just pressed it over. I hope no one has issues but hopefully if you do it just needs a slight sand.

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