This extruder is designed for the 4 screw style carriage used on the i3 rework and Reprap Wilson.
It utilizes the e3d v6 1.75mm hotend, using the PTFE tube as a guide. This design is for the MK8 drive gear, but if requested I can make a version for MK7. I can also upload a jhead version.
There are 2 fan mounts (sorry, fan designs will come later, or make your own and share).
Supports are not built in the model, but you will need them. Use your favorite slicer to generate supports. I might add some in later, but I've had better luck with the supports built by the slicer programs.
EDIT: I am adding a version with supports on the hinge. I don't know how well it will work.
Version2: I tested the supports, they seem to work. I added supports to the fan hinge flange. Supports are no longer required, but are still recommended.
Version2 has the following changes: The extruder height was increased by 2.3mm. This allows me to make the support for the bearing to be thicker/stronger. I changed the "washer" portion of the bearing holder to be wider, this should make it easier to print. The clearance around the bearing on the idler is now 0.5mm. the finger tab is 3mm longer. Because of the additional height of the extruder body, the motor screws are now counter-sunk. The clamp for the hotend is now a slightly tighter tolerance (0.1mm instead of 0.2). the tolerance around the motor flange is looser (0.2mm instead of 0). The fan hinge on the hotend clamp should be easier to print due to reduced overhang.
Version 2a: I modified the tolerances slightly, and fixed a couple errors and bugs. the support for the hinge should be easier to remove now.
Version 2b: More work on the supports. Gap is set at 0.2mm, you will still need to use a knife to remove, and do some touchup with a file. The clamp has been changed for clearance for the fan hinge. All files should be compatible with the old v2a version.
Version 2c: some changes on the idler. Not compatible with previous versions. I added a version without the ptfe (see noPTFE)
Version 2d: A Bevel was added to the filament path on no-PFTE version. This does not affect any other versions so they will stay the same. This might affect printing with flexible filaments, so if you are having trouble or plan on printing flexible filament then I suggest the v2c version.
1x 624zz Radial Bearing
1x M4 16mm Button Head Screw (Yes, it needs to be button head).
1x MK8 extruder drive gear
5x M3 25mm screws
2x M3 50mm screws
2x springs for M3 screws
10x M3 washers
2x 20mm screws
4x M4 nuts
4x M4 20mm screws (length will vary, these are for mounting to the carriage)
I am also including the BASE version of the extruder. this is for you modders out there that want to change it into a Bowden, or any other customization you require. The center of the filament hole is located at X=-4.375 Z=11
Source is available by request. It is written in openscad. I'm not sharing it here because it is currently very messy, and requires my entire openscad library to use. If you know where my github repo is, it's under scratch_work/i3_Xaxis, look for steph_i3_direct_extruder_remix.scad
Support is required. Recommended to print at 0.1mm layer height. Supports must be enabled for the entire model, not just from the build plate.
I recommend using ABS, PETG, or other high temp filament.
Clean supports and drill holes
You will need to remove the support material, and drill the holes out to remove some of the support material.
The idler hinge uses an M3 washer on both sides.
The hotend must be installed first! Before attaching the motor or drive gear. Install the hotend and feed the PTFE tube down through the hotend. Follow the directions from E3d to make sure the tube is completely seated. You can use tweezers to make sure that the collet is locked in place. Then trim the top of the PTFE tube to match the contour of the of the idler bearing and drive gear. Use another piece of PTFE tube and put it in the top (filament entrance) hole. You can use superglue to hold it in place. Trim the top tube to your liking, you can have it go all the way to your spool, or trim it flush with the top of the extruder.
The motor mounting screws might need 1-2 washers depending on your stepper. Don't over-tighten these, you're likely to damage the threads on your stepper motor.
EDIT: Following these instructions will make it difficult to remove your hotend after assembly. it would require a complete disassembly of the hotend to remove the PTFE tube. I recommend assembling your hotend first, leaving an extra length of tube coming out from the hotend. Trim this length so the hotend can slide into the groove mount. Then take another piece of PTFE tube and slide it down to butt up against the tube on the hotend. This will allow easy disassembly. I recommend you bevel the inside of the tubes where they meet with a knife or other tool to allow for some alignment offsets.