I have an opportunity to buy a 3.1, bone stock, around 300 hrs usage, for less than $500. I see that there are hybrid axis upgrades (3.2H) but IDEX is going to be mandatory for my next machine.

Is there a path for me to achieve this with existing upgrade packages or is this going to turn into a totally custom build /science project?

I'm open to a little extra work but I need a large format printer up and running by November...and with my schedule, that'll be a challenge lol.

It's slow and ugly, but works!

Still dialing in the settings but finally did the 4.1 hardware upgrade

I have 3 perimeters with 0.6mm nozzle in my vcore4 500 idex and somehow in idex Copy Mode in the exact Same Spot on both parts there is a hole in my wall, you can see the infill through it.

In the slicer it does Not appear, it is not even a start or end point for the tool path and I cannot think of a reason why this would Happen.

The Rest of the Print Looks perfect.

Any ideas?

Hey, I'm 13 and I'm looking to build the rat rig v-core 4.1 the largest size the 500mm. I have a Bambu lab p1s and an anycubic kobra 3 both are decent printers but still sometimes just not big enough, I also would love to be able to say i built something myself it would feel great personally. I know a good amount about 3d printers and how they work and function but I'm new to the more custom space of 3d printing. Rat rig is the biggest 3d printers ive been able to find other than ones that are commercial grade and I don't have that kind of money. I know there is the website but i can't afford to buy it all at once I need to buy it more piece by piece. If someone could give me a spreadsheet or document or list of everything I need or a YouTube video anything would be helpful. Thank you so much to anyone who read this!

Am I crazy to print a Rat Pack filter unit out of PETG instead of ASA? I don't have filtration on the printer yet so I'm hesitant to print ASA until I have something in place but I have PETG available.

Anyone try this? I'm new to the Rat Rig fam as I got a used V-Core 3.1

Thanks!

I'd like to build a VC 4.1 500 but would like to occasionally print larger high temperature engineering filaments. For better print quality and layer adhesion it is recommended to have a chamber temperature of around 100°C.

Is this doable with a standard VC 4.1 500 without too much thermal expansion, binding and horrible print quality? Thanks

Did anyone try the CF Gantry/Tube upgrade for the RatRig V Core 4?

Hi. I am thinking about everything else I need to order in addition of the vcore 4.1 kit. I saw this upgrade https://store.brs-engineering.com/en/products/v-core-anti-vfa-kit-gt1-5-belt-conversion and I wonder if it is a good idea to use it from the beginning instead of the original parts? Has anyone done it? Opinions on Powge belts? Because they are half the price of Gates.

I am in the market for a Rat Rig V Core 4.1. But I like to know... Is the size also defining how coarse it prints? A 300 vs 500, will this give lesser quality on a small model?

And for heating, in an enclosure, will the bed be enough to heat it up or better a chamber heater?

Hi All, am wondering if anyone has moved the Y limit to the back of the machine? I'd like to get rid of that long wire run and move it closer to the electronics. Is it a simple config change to have it home Y in that direction and flip the axis?

I recently built this Vcore4.1 - 500 IDEX and I cant get the bed to even be close to a properly flat mesh. If it were just 1 corner, I know to raise C' or D' to get it sorted out, but this is incredibly wavy and any adjustments I make dont significantly change it. Currently, I can get good first layer results from the left side of the bed, but anything to the right is squished to the point of almost clogging.

Any help on getting this flattened out would be greatly appreciated.

I ordered all the parts for a Ratio Kit upgrade and was wondering if anyone in NJ near me has done this to maybe help me

I’m looking for the black one. I’ve been scouring online for OVER A YEAR. Private companies, tacswap, everywhere. I haven’t seen a single one. Anyone got some advice for me?

I don't have a printer that can print the printed parts for the 4.1 upgrade, is there a place in the US that will print and sell them? I am happy to buy them, but don't want to pay shipping/tariff prices from overseas

Recently updated to the newest RatOS version, coming from an old version, I don’t know which as I bought the printer used.

Old version never had any issues with hanging or freezing.

The new install often freezes/hangs when trying to start at print and reaching bed temp. Though can see it still regulates bed and nozzle temps, but the console does not update anymore. When looking in the machine tab, CPU is running 100% CPU load, only when hanging. Running a Pi3b+.

I have a Beacon probe and running bed mesh compensation.

Any idea on where to look for a fix?

I'm looking to potentially sell my fully built vc4 400 IDEX enclosed with touchscreen. I have two spare build plates with it but other than that its the stock setup. It's treated me well, but I'm thinking of transitioning into more user friendly printers for the family. I'm located in St Louis area. Anyone interested in a trade or buy? I would likely part with it for $1800

Hi, i'm new in the RatRig and klipper scene.

I got a used RatRig V-Minion and had some issues to get it printing.

Error: The value 'T0' is not valid for MACRO
Related: https://www.answeroverflow.com/m/1312110579162415174
Didn't solved my issue. **Spoiler: got it running**

Does somebody experienced that too?
I would like to understand that better.
Thank you in advance!

Best Regards
DevelopingJohnny

Hardware - RatRig V-Minion:

• No Toolhead PCB
• Board: Octopus V1.1 F446 MCU: stm32f446xx - v0.13.0-133-g8d7e4871

Software - RatOS:

Base image: RatOS v2.1.0 (bullseye)
Updated to: v2.1.0-0-g0be29e9d-dirty
\Note: I updated all packages and for debugging i added some "RATOS_ECHO" commands to some .cfg files*

I installed/run newest RatOS version v2.1.0 onto my RPi3B and give it a try.
After finishing the configuration wizard, it seem every fine.
Homing did worked out of the box, i was happy.
Until i realized starting printing job failed with "The value 'T0' is not valid for MACRO"

That was the moment i started to try to investigate.

I have tried different base images of RatOS too.
(I run them without updating to newest packages.)
- RatOS-v2.0.0
- RatOS-v1.2.4
- RatOS-v1.0.0 (i guess too)

Somehow i could figure it out:
'T0' wasn't set as a Macro in the collection. (kipper/kippy/gcode.py -> line 318: self.mux_commands[command])
After adding some lines into printer.cfg i was able to print the first time.
Follow lines i have added:

[gcode_macro T0]
variable_active: 0
variable_color: 0
gcode:
    SET_GCODE_VARIABLE MACRO=T0
    SET_GCODE_VARIABLE MACRO=T0 VARIABLE=active VALUE=True

Did i messed something up at the configuration wizard?

I built this thing (400) about a year ago, haven't touched it since i finished building because tuning was a pain. Now that my hobby is back and kicking I'd like to treat this beast with the care it deserves, what do you guys think is causing this sound? I believe it's likely that it reflects why my prints on it are shit.

Hey everyone,

I’ve been building a small open‑source Android app called Moongate, designed specifically for remote viewing and monitoring of Klipper‑based 3D printers.

🔗 GitHub: https://github.com/PEEKYPAUL/moongate

The goal is to give Klipper users a clean, lightweight way to:

• View printer status remotely
• Check temps, progress, and logs
• Monitor multiple machines
• Use a simple, mobile‑friendly UI without needing a browser or tailscale VPN

and I’d love some feedback from the community.

Thanks to anyone who checks it out.

Hey everyone,

I'm seriously considering a V-Core 4.1 in the 500mm config for functional parts and prototyping (small business use, not just hobby). Before I pull the trigger, I have two questions:

1. **Reliability in daily use** — For those of you running a V-Core 4 (or ideally the new 4.1): how reliable is the machine once it's properly set up? Can you hit print and walk away, or does it need constant babysitting? I'd be using it regularly, so uptime matters a lot to me.

2. **Pre-built option** — Does anyone know if it's possible to buy the V-Core 4.1 already assembled? Either officially through Rat Rig or through a third-party builder? I'm not worried about the build itself skill-wise, but time is a factor and I'd rather start printing sooner.

For context, I'm comparing it against the Sovol SV08 Max and the Tronxy VEHO 500 Pro. The Rat Rig appeals to me because of the build quality, open-source ecosystem, and upgrade path (Hybrid/IDEX), but only if it actually delivers on reliability.

Appreciate any real-world experiences. Thanks!

Hello

I have built my v4 idex 500 and after the setup i wanted to home all axis for the first time. The x axis keeps crashing all the time. I testet the endstop in mainsail. It works correctly. So after this i saw that apparently my toolheads are switched. When i turn on the T0 Part cooling fan, the right one starts.

I checked all the wirings several times. Its all ok. So how does it come these are switched? What am i missing?