ProtoXtruder NX

Intrigued by @PrintingPerspective's great material, I wanted to convert a dual drive (I chose the HGX) to a single drive with a lever modelled on the Prusa Nextruder.

@PrintingPerspective 's great material:
https://www.youtube.com/watch?v=z2X4dc7jg4E

I wanted to see if a Nextruder-style clamping lever could be used in a HGX gear extruder....
I decided to rework @nhchiu's brilliant design.

This was meant to be a design experiment: all I had to do was cut out unnecessary parts and 'glue' a lever arrangement based on the @Prusa3D Nextruder....
But as always, the premise was simple, but as the work progressed I had to redraw the whole extruder to avoid errors in the *.stl.... files and to make this remix work.

The mounting dimensions are the same as in the original ProtoXtruder, only the 24.6mm dimension will change to 24.8mm and therefore the 6.3mm dimension will change to 6.4mm.
 

   To build the ProtoXtruder NX you will need:

1. HGX lite kit (affiliate link)- kit parts needed for ProtoXtruderNX:
 - MR63ZZ bearings x 2pcs
 - 3mm shaft (16mm length) x 1pcs

Instead of one original 3x16 shaft from the HGX kit, I recommend the following solution DIN 6325 3x16 mm m6 steel cylindrical mandrel as an axle for the large filament wheel.

 - 3mm shaft (24mm length) x 1pcs
 - large filament gear with pin bearing x 1pcs
 - reduction gear x 1pcs  
 - heat inserts (M3 x D4.5 x H5) x 2pcs
 - M3x8mm BHCS x 1pcs
 - M3x20mm SHCS x 3pcs

2. Other parts needed for extruder and lever system:

 - M3x6mm SHCS x 1pcs
 - M3x20mm BHCS x 2pcs
 - M5 precision shim 7x0.1mm x 1pcs (affiliate link) you can use a properly cut shim from 0.08-0.1mm thick paper
 - Tubular spacer 4x3x8.5mm x 1pcs - I made one out of a brass tube that I have(affiliate link)

 - pin 3x7.5mm x 2pcs or pin 3x8mm x 2pcs (I cut a free pin 3x16 from the HGX gearbox)

 - 683ZZ bearings with U-groove x 2pcs (affiliate link)
 - M3x20mm BHCS x 2pcs
 - M3 nyloc nut x 2pcs
 - spacer 6x3.1x8mm x 1pcs (affiliate link)

 - M3x50mm SHCS x 2pcs trimmed to M3x36.5mm see update 05.01.2025

 - Spring 5x15x0.8mm x 2pcs (affiliate link)- I made two from the long one I bought earlier(affiliate link)

***For the archive version v1, instead of M3x36.5mm SHCS x 2pcs, M3x35mm SHCS x 2pcs will be needed***

Most of the parts are modelled on those needed for the Nextruder lever assembly from Prusa.

3. NEMA 14 36mm pancake motor with 8T gear or 10T gear (affiliate link).

   Klipper settings.

I recommend the settings suggested by Bondtech for the LGX (HGX is a clone of the LGX). Bondtech recommends:

rotation_distance: 5.7 #calculated rotation distance - the rotation_distance needs to be adjusted
#rotation_distance: 55 #use this with gear ratio 
#gear_ratio: 44:10, 37:17 #use this with rotation_distance 55  

you can also enter (the previous way is recommended):

#rotation_distance: 5.7 #calculated rotation distance
rotation_distance: 55 #use this with gear ratio - the rotation_distance needs to be adjusted
gear_ratio: 44:10, 37:17 #use this with rotation_distance 55

   Print settings.

Nozzle 0.4, layer 0.2, infill 40%, 4 perimeters.

We print without the supports on.

ABS/ASA recommended.

The design considers a print with a layer height of 0.2mm.

However, in order for the parts to fit correctly, the back of the case (newBACK) and both halves of the lever arm (idlerAlever, idlerBlever) have the highest surfaces in multiples other than 0.2mm.

Therefore:
- idler Lever A and idler Lever B should be printed on a separate printout with the 'Precise Z Height' option enabled.

- The newBACK should be printed on a separate print with the 'Precise Z Height' option enabled.
I have added the swivelLever to this print as it is lower than the newBACK and will not interfere with the precise printing of the last surface of the newBACK.

   After printing

After printing the idlerBlever, the integral support (the grey part in the photo) must be carefully removed.            

   Assembly.

I have added tips and assembly instructions in a pdf file.

Instruction file: protoxtrudernx-with-ir-main-assembly-en-v0

This is the latest version — you can use it when assembling the ProtoXtruder NX v2. During assembly, skip the section related to the IR sensor. 

‼ Keep in mind that in the version without the IR sensor, the lever tension screws should be M3x36.5 mm, not M3x41.5 mm as in the IR sensor version ‼

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Updated 16.10.2025

Updated description.
I’ve added the extruder assembly and an additional installation guide.

Instruction file: protoxtrudernx-with-ir-main-assembly-en-v0

This is the latest version — you can use it when assembling the ProtoXtruder NX v2. During assembly, skip the section related to the IR sensor. ‼ Keep in mind that in the version without the IR sensor, the lever tension screws should be M3x36.5 mm, not M3x41.5 mm as in the IR sensor version ‼

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Updated 12.09.2025
I took into account the information from @WowWi_1965943 and added the idlerALEVER and idlerBLEVER (v3) versions adapted for 8mm shafts. Now it’s possible to use 3x7.5mm or 3x8mm shafts.

I’ve also added STEP files for the ProtoXtruderNX parts.

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Updated 07.07.2025
Updated Klipper settings description.

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Updated 14.06.2025
Updated description.

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Updated 08.04.2025
Updated description.

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Updated 04.03.2025
Updated description.

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Updated 12.02.2025
Updated description.

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Updated 30.01.2025
Updated description.

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Updated 09.01.2025

I have updated the installation manual.

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Updated 05.01.2025

I have added screw-guideM3x36.5.stl for M3x36.5mm screws.

This is a purely functional improvement:
Earlier versions of the design used screws in the lever clamping mechanism: M3x35 mm.
As can be seen in the attached drawing, when changing the filament, the screw threads would wear out the guide holes in the front of the housing over time:

The solution to this problem is M3x50 screws cut to M3x36.5mm so that the threaded part of the screw is at least 5.5mm long. Taking into account the quality of the bolts, I assumed that for an M3x50 bolt the non-threaded part is 31mm long. Then, in the guide holes of the front part of the housing, the M3x36.5mm screw will slide over the unthreaded part:

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Updated 28.11.2024

To celebrate 20 downloads, I have added a new version of newFRONT_COLLET_v3 based on the latest original version of ProtoXtruder @nhchiu.

If you want to know how to assemble the ProtoXtruderNX_SwiwelLEVER_v3, check out the assembly instructions I prepared for the swivel-idler for the original Nextruder @Prusa3d:

https://www.printables.com/model/1080422-prusa-nextruder-idler-swivel-r2-with-no-gap-mod

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Updated 24.11.2024

After testing the v2 version, I have returned the nutLEVER v0 version - it is more functional.
I'll leave the bulk version v1 for permanent download - it's the lightest version with a lever modelled on the Prusa Nextruder.
The whole nut-swivel-lever arrangement is interchangeable between v1 and v2 and newer versions.

I added a bolt-on M2x10mm version of swivelLEVER_v3.
I will update the assembly instructions in the near future.

I have added a revised version on newFRONTptfe2_v3 and two new versions: PC4_M6 and ECAS04 modelled on the original ProtoXtruder @nhchiu.

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Updated 24.11.2024

After testing the v2 version, I have returned the nutLEVER v0 version - it is more functional.
I'll leave the bulk version v1 for permanent download - it's the lightest version with a lever modelled on the Prusa Nextruder.
The whole nut-swivel-lever arrangement is interchangeable between v1 and v2 and newer versions.

I added a bolt-on M2x10mm version of swivelLEVER_v3.
I will update the assembly instructions in the near future.

I have added a revised version on newFRONTptfe2_v3 and two new versions: PC4_M6 and ECAS04 modelled on the original ProtoXtruder @nhchiu.

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Updated 18.11.2024

I have improved the pdf manual to version 5.

I didn't have time to print version 2 so I left version 1 as tested.

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Updated 17.11.2024

The previous version 1 is a fully functional design.

I didn't have time to print version 2 so I left version 1 as tested.

I have added version 2 - it is improved - with improvements to the pressure lever mechanism and newFRONT.
I was inspired to create version 2 by some improvements in the original @Prusa3D Nextruder lever dedicated to the MMU3.
The list of parts needed for ProtoXtruderNX_v2 has not changed.
Only the printed parts have changed and I have added a new part: ProtoXtruderNX_screwGUIDE_v2
By default, ProtoXtruderNX_NewFRONT has two versions:
1. protoXtruderNX_newFRONTptfe1_v2
for direct mounting of a ptfe tube of your own design - see point 6* of the pdf manual.
2. protoXtruderNX_newFRONTptfe2_v2
for direct mounting of a ptfe tube based on the original PortoXtruder design.

When I find some time I will add an updated pdf manual.

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Updated 13.11.2024

I have improved the pdf manual to version 4.
I improved the part: ProtoXtruderNX_NewFRONT_v0, so that the two M3x35mm screws work properly with the 5x15 springs to push the lever.
As you can see from the photos, my prototype had to add washers between the springs and the newFRONT to properly adjust the lever pressure - the newFRONT versions v1 introduced eliminate this flaw.

I have prepared two versions of the new ProtoXtruderNX_NewFRONT

1. ProtoXtruderNX_newFRONTptfe1_v1
for direct mounting of a ptfe tube of my own design - see point 6* of the pdf manual.

2. ProtoXtruderNX_newFRONTptfe2_v1
for direct mounting of ptfe tube based on the original PortoXtruder design.

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