PROTOTYPE half-tested Captive Nylon/T-Glase Extruders -- for sho

Summary These extruder designs are heavily modified quick-fit-compatible extruders based loosely on the Gregs-Wades initial design. What I've done in each case is enlarge the filament drive path to 6.75mm to accommodate a piece of PTFE tubing, either through the bottom half of the extruder or through the whole extruder body. (This is 1/4" OD 1/8" ID tubing, PERFECT for 3mm filament) This essentially turns the traditional Gregs into a Flexible-Filament compatible extruder!!! Although the tolerances may not be good enough for something like Ninjaflex, I've noticed that slightly flexible materials like Nylon blends and T-Glase/PETT are just a little too flexy when not captive. This solves that issue and prevents over-pressure in the hotend, which leads to the bolt stripping your filament as it feeds and re-feeds... and stops your prints dead in their tracks! Note, even though the filament is captive, you will still need a tight idler bearing to keep the material pressed up against the hobbed bolt in version 8. Version 9 encapsulates the tubing completely, and uses an embedded heat-sink M5 Nut to apply an additional screw if needed (just like the FlexyStruder). This is not needed in most cases. There will be some uncomfortable overhangs in V8. This post was made chiefly to demonstrate concepts during a conversation on reprap IRC.