CNC Toolhead for the RatRig VCore 4/4.1

• Update 22.05.2026:

  • Added EBB42 Gen2 toolboard mount for the Hextrudort Plus extruder

• Update 16.03.2026:

  • Removed 4.0 files to complete the 4.1 transition

• Update 25.02.2026:

  • Added EBB36 Gen 2 toolboard mount for the Orbiter extruder using the Smart Filament Sensor

• Update 20.02.2026:

  • Updated all the CPAP part cooling ducts to feature better and smoother air flow, with the added benefit of being able to run the Beacon cable in the same fashion as the 4.1 partcooling duct.They also feature the Beacon probe being mounted closer to the nozzle, as per the VCore 4.1 (Chube has a bigger offest, as usuall, details below)

  • Fixed an typo in the BOM, M3x20 screws is needed for all toolboard mount

  • Orbiter O2S toolboard mount fixed to fit M3x20 screws

  • Removed all CPAP part cooling ducts that have been based on the 4.0 as they are inferior.

• Update 11.02.2026:

  • Adapted the 4.1 4028 partcooling duct for the Chube and Goliath. Also moved the 4028 for the Rapido variant up by 1 mm, so that all variants use the same Upper Mount $ Grill piece.

  • Added side exhaust 4010 Rapido hotend cooling duct.

  • Added new 4.1 endstop mounts to be inline with the 4.1 in the Configurator which has different  endstop locations. If the 4.1 parts are used, please select the 4.1 in the Configurator aswell

  • Removed all 4028 part cooling ducts that have been based on the 4.0 as they are inferior.

• Update 26.01.2026:

  • Adapted the 4.1 4028 partcooling duct for the Rapido

Hello!

A small story about the CNC toolhead: 
I was not very pleased with the stock RatRig toolhead and being locked in using certain hardware so I set out to design a toolhead that offers a lighter weight, more rigidity for the bigger hotends, compatibilty with different hardware and easy to work on.

Special thanks to the VZBot team and their CNC toolhead which was used as inspiration and Luke's Laboratory for the hotend bolt pattern idea! 

If you have a VCore 4, by utilizing this toolhead, you are “upgraded” to the 4.1 since the endstop and Beacon location are change to be in compliance with the 4.1 config, therefore the 4.1 has to selected in the RatOS configurator.

This toolhead allows for the following configuration options: 

Extruders (using different adaptor plates):

• Orbiter

• Hextrudort Low

• Hextrudort Low Watercooled

• Hextrudort Low Plus

• Hextrudort Low Plus Watercooled

• LGX Lite / Lite Pro

• Sherpa Mini

Hotends (bolt on directly to the top plate): 

• Rapido 1 UHF

• Rapido 2 UHF

• Rapido Ace UHF

• Dragon ACE UHF

• Goliath Air

• Goliath Watercooled

• Triangle Labs CHC XL Air (uses the same printed parts as for the Goliath)

• Triangle Labs CHC XL Watercooled (uses the same printed parts as for the Goliath)

• Chube Air

• Chube Conduction with a different top plate

• Mosquito Magnum+ (uses the same printed parts as for the Chube, including the probe Y offset)

• Mosquito Magnum+ Conduct (since it is such a small hotend height wise, a spacer is needed to make it the same lenght as the Rapido UHF and can be found below, designed to be milled from metal)

Toolboards:

• EBB42

• Orbitool O2S

• EBB42 Gen 2

Part cooling solutions (working on adating the 4.1 duct):

• stock 4028 fan 

• CPAP

Same Beacon cable routing as the stock 4.1 toolhead

Hotend cooling solutions:

• stock 4010 fan 

• 2510 fan  

Currently, the CNC parts can be bought from: 

• Mandala Roseworks 

• Mellow AliExpress

• Raven 3D Tech

• BRS Engineering

When using the Chube Air or Chube Conduction, the y offset for the Beacon probe needs to be increased since the probe has the been moved back so that it is not affected by the radiating heat. Therefore, the following has to be added to your printer.cfg:

[beacon]
y_offset: 24.3

Below you can find all the printed parts I managed to design for the most popular configurations I saw the RatRig community wanting to be implement, along with obfuscated models of each toolhead (Hybrid or IDEX T0 and T1) so that everybody is able to design new printed parts for the toolhead.

Hope you enjoy this new toolhead!

If you enjoy my designs and want to support me, you can buy me a coffee here.

Print settings

• 0.2 layer height

• 0.45 extrusion width

• 4 wall, 6 bottom and top layers

• 30 - 40% Gyroid infill

• the 4028 ducts have built in supports, do not split that part into pieces, just orient it on the face with 3 holes

Assembly Manual

Prerequisites and additional preinstall information:

• This assembly manual will refer to the CoreXY, Hybrid and IDEX configurations (from now on, the CoreXY and Hybrid configurations will be referred to as CoreXY since from the toolhead perspective, they are exactly the same)

• Ensure that you already printed the printed parts (if the VC4 is your only printer) required for installing the tool board, end stop / end stops, part cooling and hot end cooling

• Switching from the stock VC4 toolhead to the CNC version will require the belts to be cut shorter (switching back to the stock toolhead with the shorter belts will not be possible and new longer belts will be required)

• Ensure that both belts are the exact same length;

• Adding blue Loctite to the threads of the screws is optional, I did not encounter any screws loosening during my time testing the CNC parts (more than 7 months) since they are interacting with metal and not a plastic that can creep but your experience might not be the same.

• BOM: 

  • M3 heat inserts (Voron size)

  • 6 x M3x4 mm countersunk screws (bottom plate and endstop mount)

  • 7 x M3x6 mm countersunk screws (top plate and extruder adaptor plate)

  • 2 x M3x20 button head screws (used for mounting the toolboard mounts)

  • mounting the hardware (toolboard, extruder, endstop, fans) requires reusing the screws provided by RatRig

Belts Installation

CoreXY Configuration

• Loosen both lower belt tensioners (My recommendation would be to take out the set screw that tightens the tensioners and adjust the tensioner so that the end of the tensioner is not visible when looking through the hole where the set screw is supposed to be; this way you ensure that you do not cut the belt too short) Make sure that both tensioners are adjusted to the same depth.

• If you received the toolhead or toolheads assembled, please go ahead and disassemble them completely, taking note of each screw and part; Installing the belts requiredsspace and having each of the front arms and back plate/plates as a single unit makes this process a lot easier.

1. Installing the belts in the back plate

• From the inside out, pass the end of the top belt through the top belt slot. Note that the teeth of the belt should be facing the extrusion or the front of the printer.

• Fold the end of the belt so that the teeth of the belt interlock, at least 5 to 7 teeth. Take note of how many teeth you used to interlock; the same number must be used for the lower belt.

• Push the folded belt back into the belt slot so that the teeth are held interlocked by the sides of the slots.

• From the inside out, pass the end of the lower belt through the lower belt slot.

• Fold the end of the belt so that the teeth of the belt interlock, same number of teeth as for the top belt.

• Push the folded belt back into the belt slot so that the teeth are held interlocked by the sides of the slots. 

• At this point, you can pull by hand on each of the belts, from the inside so that you can check if the belts are secure or not which depends a lot by the manufacturing tolerances:

  • if the belts do not slip out, you are good to go, belts are secured by the loop that is created on the outside of the belt slot;

  • if they do slip out when being pulled by hand, an extra step must be taken in order to secure the belts; that is to add a 9 mm piece of filament or even piano wire in the belt loop on the outside of the back plate and after that pull the belt toward the inside and it should be secure

2. Installing the belts in the front arms (will add pictures at a later point, in a few days, but it looks the same as above)

• Take the right front arm and thread the belt through the belt slot.

• Fold the end of the belt so that the teeth of the belt interlock.

• Push the folded belt back into the belt slot so that the teeth are held interlocked by the sides of the slots.

• Take the left front arm and thread the belt through the belt slot.

• Fold the end of the belt so that the teeth of the belt interlock.

• Push the folded belt back into the belt slot so that the teeth are held interlocked by the sides of the slot.

• The belt length and number of interlocking teeth is not important at this stage, belt lengths will be adjusted after the toolhead is assembled.

• At this point, you can pull by hand on each of the belts, from the outside so that you can check if the belts are secure or not which depends a lot by the manufacturing tolerances:

  • if the belts do not slip out, you are good to go, belts are secured by the loop that is created on the inside of the belt slot;

  • if they do slip out when being pulled by hand, an extra step must be taken in order to secure the belts; that is to add a 9 mm piece of filament or even piano wire in the belt loop on the inside of the front arm and after that pull the belt toward the outside and it should be secure

IDEX Configuration

• Loosen both lower belt tensioners (My recommendation would be to take out the set screw that tightens the tensioners and adjust the tensioner so that the end of the tensioner is not visible when looking through the hole where the set screw is supposed to be; this way you ensure that you do not cut the belt too short) Make sure that both tensioners are adjusted to the same depth.

• If you received the toolhead or toolheads assembled, please go ahead and disassemble them completely, taking note of each screw and part; Installing the belts requiredsspace and having each of the front arms and back plate/plates as a single unit makes this process a lot easier.

1. Installing the A belt in the back plate of T0 (please refer to the pictures above, do not currently have an IDEX set to take pictures of, will add them as soon as possible)

• From the inside out, pass the end of the A belt through the belt slot of the T0 back plate. Note that the teeth of the belt should be facing the extrusion or the front of the printer.

• Fold the end of the belt so that the teeth of the belt interlock, at least 5 to 7 teeth. Take note of how many teeth you used to interlock; the same number must be used for the B belt.

• Push the folded belt back into the belt slot so that the teeth are held interlocked by the sides of the slots.

• At this point, you can pull by hand on each of the belts, from the inside so that you can check if the belts are secure or not which depends a lot by the manufacturing tolerances:

  • if the belts do not slip out, you are good to go, belts are secured by the loop that is created on the outside of the belt slot;

  • if they do slip out when being pulled by hand, an extra step must be done in order to secure the belts; that is to add a 9 mm piece of filament or even piano wire in the belt loop on the outside of the back plate and after that pull the belt toward the inside and it should be secure

2. Installing the B belt in the back plate of T1

• From the inside out, pass the end of the B belt through the belt slot the T1 back plate.

• Fold the end of the belt so that the teeth of the belt interlock, same number of teeth as for the A belt.

• Push the folded belt back into the belt slot so that the teeth are held interlocked by the sides of the slots.

• At this point, you can pull by hand on each of the belts, from the inside so that you can check if the belts are secure or not which depends a lot by the manufacturing tolerances:

  • if the belts do not slip out, you are good to go, belts are secured by the loop that is created on the outside of the belt slot;

  • if they do slip out when being pulled by hand, an extra step must be done in order to secure the belts; that is to add a 9 mm piece of filament or even piano wire in the belt loop on the outside of the back plate and after that pull the belt toward the inside and it should be secure

3. Installing the A belt in the front left arm of T0 (refer to the CoreXY guide for pictures)

• Take the left front arm and thread the A belt through the belt slot.

• Fold the end of the belt so that the teeth of the belt interlock.

• Push the folded belt back into the belt slot so that the teeth are held interlocked by the sides of the slots.

• The belt length and number of interlocking teeth is not important at this stage, belt lengths will be adjusted after the toolhead is assembled.

4. Installing the B belt in the front right arm of T1 (refer to the CoreXY guide for pictures)

• Take the right front arm and thread the B belt through the belt slot.

• Fold the end of the belt so that the teeth of the belt interlock.

• Push the folded belt back into the belt slot so that the teeth are held interlocked by the sides of the slot.

• The belt length and number of interlocking teeth is not important at this stage, belt lengths will be adjusted after the toolhead is assembled.

Assembling the CNC toolhead (this part will refer to both configurations, CoreXY first / IDEX second)

• Screw the top plate / top plates to the carriage / carriages by using 4 M3x6 mm / 8 M3x6 mm countersunk screws.

• Screw the back plate/ back plates to the top plate / top plates by using 2 M3x6mm / 4 M3x6 mm countersunk screws.

• Screw the front arms to the top plate / top plates by using 2 M3x6mm / 4 M3x6 mm countersunk screws.

• Screw the bottom plate / bottom plates to the back plate and front arms / back plates and front arms by using 4 M3x4 mm / 8 M3x4 mm countersunk screws. Make sure that the outside of the front arms are aligned with the top and bottom plate and not skewed before tightening the screws.

Front Belt Adjustment

• At this point, the belt lengths can be adjusted since the toolhead is assembled.

• Push or pull the front belt loops and adjust the belt lengths:

  • If the belt are too long, increase the number of interlocking teeth in the front belt loops. Make sure to have the same teeth interlocking on each belt so that the belts are the same length.

  • If the belts are too short, decrease the number of interlocking teeth in the front belt loops. Make sure to have the same teeth interlocking on each belt so that the belts are the same length.

• Belts can now be cut to be shorter if there is excess belt sticking out of the front arm, there should not be more than 1 or 2 teeth worth of belt sticking out of the front arms since it would interfere with the bearing stacks when at either end of full X travel 

Hardware Installation

• Install the hotend of your choosing:

  • if you are installing the Rapido, the Goliath, the Dragon or Triangle Labs CHC XL, the RatRig supplied M2.5 screws can be reused

  • if you are installing the Chube, 6 M3x6 mm button head screws can be used to secure it to the top plate (these most probably will have to be self sourced)

• if you are using the Hextrudort (Low or Low Plus) or any of the LGX variants, you have to unscrew the stepper from the extruder and install the body to the adaptor plates using 2 M3x4 mm countersunk screws in case of the Hextrudort or 4 M3x6 mm countersunk screws in case of the LGX variants (metal versions might require shorter screws)

• if you are using the Orbiter, the adaptor plate can be attached directly to the top plate using 3 M3x4 screws

• add a longer piece of filament and test how long it should be (I recommend having a bit of PTFE compression regardless of hotend)

• in case of the Orbiter, attach the extruder to the adaptor plate using 2 M3x8 button head screws, the ones supplied by RatRig can be reused

• attach the newly formed assembly comprised but the extruder top plate and the extruder body to the top plate using 3 M3x4 mm countersunk screws (skip this step in case the Orbiter is used)

• attach the extruder stepper motor back to the extruder body

• insert 2 heatset inserts into the endstop mount (in the case of IDEX, 4 heatset inserts in both endstop mounts), screw the stock endstops to the endstop mounts using the RatRig supplied M3 screws screws and screw the entire assembly to the top plate using 2 M3x4 mm countersunk screws (in the case of IDEX, T0 has the endstop mounted on the left side of the top plate and T1 on the right side)

• the toolboard mounts for the EBB42 have been designed around using 2 M3x20 mm screws, shorter than the RatRig ones.

Until this point, I think I have covered everything that is new with this toolhead and that would require additional information.

With the variety of toolboard mounts, part cooling and hotend cooling options, it would be quite difficult to cover every single configuration possible but due to the nature of the new toolhead, it is quite self-explanatory of how the rest of the parts should be mounted.

For any questions or requests, you can mesage me here or you can find me in the RatRig Discord server under the username: cristian__i

Took the stock toolhead and designed a CNC version inspired by the VZBot CNC toolhead.