Wanhao i3 v2.1 Hero Me Gen7 carriage adapter with reinforcement.

I bought an used Monoprice Maker Select v2 (aka Wanhao i3 V2.1) printer, and didnt really liked the stock hotend and extruder. The stock belt tentioning method wasn't to my liking as well. I found HeroMe Gen 7 platform, and printed all parts, but the "Reprap i3 Prusa clones X carriage" lacked belt tensioning, and required the whole X-axis to be dissasembled in the install process. Also, it seemed to me that only four threaded inserts in HMG7 base piece holding the whole printhead stack to X carriage wouldn't be stiff enough. 

So I created my own X-carriage with belt tensioning built-in, large Gantry adapter plate and reinforcement riser with two more screws attaching HMG7 stack to Gantry adapter. I tried to maintain the nozzle height and the end stop position as close to stock as I could. 

A clone of E3D V6 hotend and a clone of Bondtech BMG Dual Drive Extruder was used for this exact printhead. Maybe it'll work on other i3 clones, but I haven't tested that.

Result can be used as a Printhead Hotswap Platform, and I also made a dial indicator holders for this X-carriage. 

Parts needed:

1 pc M3x35 mm screw (reusing one from an extruder motor mount in stock Wanhao i3)

2 pcs M2x8 mm screw (reusing the ones holding an X endstop switch in stock Wanhao i3)

8 pcs M4x10 mm screw (reusing six screws holding a linear bearing to metal bracket in stock Wanhao i3 and two extra)

~65cm of 2GT-6 Timing Belt 6mm wide, 2mm per teeth (The belt from stock X-axis Wanhao i3 should be enough)

5 pcs M3 heat set threaded inserts (⌀4.5mm OD, 6mm length) 

10 pcs M3 heat set threaded inserts (⌀4.5mm OD, 4mm length)

2 pcs M3x20 mm screws

12 pcs M3x8 mm screws

plus any hardware your HMG7 stack will require.

Printing Instructions:

Print models in original orientation. Supports only needed on cable chain holder of gantry base. Overhangs inside holes are printed as multiple bridges, no supports needed.

Layer height: 0.2mm

Top layers: 4

Bottom layers: 3

Perimeters: 3

Infill: support cubic 30% at least. 

Some parts of X-carriage on my photos are slightly different from STEP files in this project, that's because I haven't reprinted the latest version of every part. The models in this project are the latest and more matured versions.

Assembly preparation (installing inserts):

1. X-carriage belt tensioner: Install one long (6mm) M3 threaded insert at the end of block
2. X-carriage base: Install two short M3 threaded inserts (M3 4mm) into cable chain holder on the top of a gantry base. Install two long (6mm) M3 threaded inserts into two offset holes in the middle of the base (make sure they're flush and don't stick out)
3. Gantry adapter plate: Install eight short (4mm) M3 threaded inserts along the perimeter of a plate, as shown in photo.
4. Reinforcement riser: Install two long (6mm) M3 threaded inserts at the end, as shown in photo. 

Assembly instructions:

X-carriage:

1. Using 8 pcs M4x10 screws attach Gantry Base to linear bearings on X-carriage base. Belt attachment part must be between linear rods.
2. Insert the one end of a timing belt into the Belt Tensioner. 
3. Install the tensioner into the X-carriage base (left side) as shown on photo.
4. Slide a long M3x35 mm screw in X-carriage base (from right side, between belts) and screw in into belt tensioner by several turns.
5. Route the belt through X-axis assembly the same way as in stock Wanhao i3
6. Insert the belt into X-carriage base part (right side)
7. Tension the belt by screwing M3x35 screw (and moving the belt tensioner). I used the Prusa MK4 assembly instruction to understand the required belt tension. https://help.prusa3d.com/guide/5-nextruder-assembly_529772#541872 
8. If the belt is still too loose even when tensioner is at the most right position inside the X-carriage base - pull the belt out of X-carriage, snip one tooth from the end of the belt and repeat from step 6. 
9. After the belt is tensioned install the belt cover and screw two M3x20 mm screws through belt cover, belt tensioner into X-carriage base. They should be screwed tight.
10. Using two M3x8 mm screws attach cable chain to X-carriage base. You can use the countersunk screws that attach cable chain to stock Wanhao i3 X-carriage.
11. Using two M2x8 mm screws attach X-axis endstop to the top right of X-carriage base from the back side your the printer. There are corresponding holes for M2 screws in X-carriage base.
12. The hardest part is over. Yay!

HeroMeGen7 Stack (base, fans, hotend, riser, extruder) and Gantry adapter plate:

I installed several cable connectors to all wires coming into X carriage for ease of assembly and disassembly of HMG7 stack aka extruder assembly aka printhead.

1. Assemble The HMG7 stack as usual, inserting reinforcement riser on top of hotend mount.
2. Using six M3x8 mm screws attach Gantry adapter plate to your HMG7 stack

The whole prinhead:

Now you can attach Gantry adapter plate with extruder assembly to X-carriage base using eight M3x8 screws from the back side of the printer.

At this time I need to reattach all the cable connectors of printhead, but your mileage may vary.

You'll need to re-calibrate heatbed of Z-offset and maybe Y-axis endstop offset (I didn't needed to). 

And that's all, happy printing!

If you'll print this project, please please post a photo to “makes” section!