Update 10/24/2019
Since I was pretty new to Fusion360 when I originally created this, I wanted to clean it up before releasing the model, but it has been months and I haven't had time and I won't for the foreseeable future, so I'm uploading the f3d file as-is.

Update 3/29/2019
Added a spacer for the Y axis endstop to allow it to contact the endstop. It is designed to use a square m3 nut and ~10mm m3 screw to hold it in place.

I like my Maker Ultimate but never liked the hotend that came with it. It was difficult to get good part cooling for it. I wanted to switch to an E3D hotend but there weren't too many options, especially ones which use the original extruder, so I designed my own.

This is v1. It's not perfect but it gets the job done. I plan to rework it in the future and possibly make a version to work with a bowden extruder.

• Actually has a few more mm clearance than the stock hotend.
• Uses the original LM6UU bearings (warning: they can be a little tight. I tapped mine in with a hammer and appropriately sized cylinder used as a punch. Be careful doing this).
• Built-in part cooling fan mount + ducts. Takes a common 50x15 blower. Make sure you get the 24V version.
• Front hotend cooling fan is a 30x10mm axial fan, also 24V.
• Works with stock PT100 temperature probe as long as you get the e3D heater block that accepts a cartridge-style temperature sensor.

I created this using e3D drawings for the v6, but i actually use a clone and it fits just fine.

Non-stock parts needed:

• 1x 24V 50x15mm radial fan
• 1x 24V 30x10mm axial fan
• 1x 24V heater cartridge (40W works well)
• 1x Genuine or clone e3D hotend with cartridge style temperature sensor block
• 2x m3 square nuts
• 2x m3x18 screws
• 1x m3x22 screw
• < 100mm of 4mm O.D. PTFE tubing for 1.7mm filament

Stock parts re-used:

• PT100 temperature probe
• LM6UU bearings
• Extruder mount and everything that goes with it

NOTE
The top front of this carriage protrudes a bit further forward than the stock one by about 1cm, so the Y-axis endstop doesn't quite reach without some minor modification. The Y-Axis endstop spacer helps with this.

Monoprice

Maker Ultimate

No

Yes

0.2

20% Grid

Mainly supports are needed for the arch in the hotend cover. I also used supports under the air ducts, but I'm not sure it's necessary.