Large-format open CoreXY kit in 300/400/500 mm sizes, optionally hybrid-CoreXY or IDEX.
300 x 300 x 300, 400 x 400 x 400 or 500 x 500 x 500 mm. Sortable value is the 300 mm kit
Advertised dimensions; check usable space and variants.
Open by default; enclosure panels sold separately
Published enclosure and chamber-heating notes.
$2,319.99 at Fabreeko for the fully-specified US kit (price includes shipping and duty in the continental USA), Batch 4, checked Aug 2026. 300 mm ABS-parts variant in stock, 400 mm down to one unit. Rat Rig's own base kit is priced separately in EUR
Dated listing, not a live offer. Read the configuration and region.
Understand the hardware, explore compatible changes and find a diagnostic starting point when something goes wrong. Expand the specification sections for every recorded value, condition and original reference.
Dimensions, construction and the hardware that moves the print.
| Property and unit | Published value and conditions | Sources and dates |
|---|---|---|
| Manufacturer & exact marketed model name (verify the exact product identity first) | Rat Rig V-Core 4, sold in the US as "RatRig V-Core 4 3D Printer Kit" | 1 source
|
| Street price (USD; dated snapshot per entry) | $2,319.99 at Fabreeko for the fully-specified US kit (price includes shipping and duty in the continental USA), Batch 4, checked Aug 2026. 300 mm ABS-parts variant in stock, 400 mm down to one unit. Rat Rig's own base kit is priced separately in EUR | 2 sources
|
| Variants & sibling models — and how to tell them apart (spec-contamination risk) | Three sizes (300, 400, 500 mm cubes) and three motion configurations: Standard CoreXY, Hybrid CoreXY (+$149.99, adds two motors to Y), and IDEX with two independent toolheads (+$450.00). Superseded by the V-Core 4.1. Raspberry Pi and enclosure panels are not included | 2 sources
|
| Market position: superseded? successor announced? | Superseded by the V-Core 4.1, which adds a steel X gantry, a full-metal toolhead, improved part cooling, 8 mm beds on the 400 and 500 sizes and pre-made cables. Rat Rig sells a 4.1 upgrade kit for existing V-Core 4 owners | 1 source
|
| Property and unit | Published value and conditions | Sources and dates |
|---|---|---|
| Build volume X×Y×Z (mm) — advertised vs actually usable | 300 x 300 x 300, 400 x 400 x 400 or 500 x 500 x 500 mm. Sortable value is the 300 mm kit | 2 sources
|
| Frame construction & material | 30-series aluminium extrusion with printed ABS structural parts | 2 sources
|
| Enclosure: open / enclosed; panel material; door/lid | Open by default; enclosure panels sold separately | 1 source
|
The official kit page links its bill of materials and chapter-by-chapter conversion guide. Use that selected build’s printed-part requirements alongside the hardware kit; stock 4.0 parts are not a substitute for every revised assembly.
Applies to: V-Core 4.0 to 4.1 conversion, matching size and CoreXY / Hybrid / IDEX route. The purchased upgrade kit does not contain printed parts.
The manufacturer’s conversion introduces a steel X gantry, full-metal toolhead and Orbitool O2S wiring. Choose the kit by machine size and by both the existing and intended CoreXY, Hybrid or IDEX configuration.
Applies to: Existing V-Core 4.0. Printed parts are excluded from the kit and must be obtained separately; Rat Rig pairs the conversion with RatOS 2.1.
| Property and unit | Published value and conditions | Sources and dates |
|---|---|---|
| Kinematics (bedslinger i3 / CoreXY / other) | CoreXY, or Hybrid CoreXY, or Hybrid CoreXY IDEX depending on the configuration ordered | 1 source
|
| Stepper drivers (exact model e.g. TMC2209; UART/SPI; sensorless homing?) | TMC2209 | 1 source
|
Extrusion, heating, leveling and material handling.
| Property and unit | Published value and conditions | Sources and dates |
|---|---|---|
| Type (direct drive / bowden) & design name | LDO Orbiter 2.0 direct-drive extruder | 1 source
|
| Property and unit | Published value and conditions | Sources and dates |
|---|---|---|
| Hotend design (proprietary/standard; quick-swap mechanism?) | Phaetus Rapido 2.0 UHF | 1 source
|
| Property and unit | Published value and conditions | Sources and dates |
|---|---|---|
| Bed surface (material, texture, coating), single/double-sided | Keenovo silicone bed heater | 1 source
|
| Property and unit | Published value and conditions | Sources and dates |
|---|---|---|
| Auto bed leveling: probe technology (inductive / strain gauge / load cell / touch probe) | Beacon eddy-current probe | 1 source
|
| Property and unit | Published value and conditions | Sources and dates |
|---|---|---|
| Part-cooling fan(s): count, size, ducting design | Nidec 4028 part-cooling fan | 1 source
|
Firmware, controls, connections and calibration.
| Property and unit | Published value and conditions | Sources and dates |
|---|---|---|
| Mainboard model & MCU (exact chip markings if teardowns exist) | BigTreeTech Octopus | 1 source
|
The migration guide calls out changed pin assignments, duplicate configuration and older Beacon-related customizations. Compare the wiring and generated configuration with the current model’s defaults before restoring custom sections.
Applies to: RatOS 2.1 RC3-to-RC4 transition. Stock-wired V-Core 4.0/4.1 kits differ from custom board and accessory layouts.
RatOS supplies the printer configuration and supporting Klipper workflow. Its setup wizard distinguishes V-Core 4.0 and 4.1 and generates supported hardware options, including IDEX. Back up custom configuration and follow the documented migration rather than carrying an old configuration forward wholesale.
Applies to: V-Core 4.0 / 4.1. The RC3-to-RC4 migration requires a fresh SD-card installation; custom board wiring needs explicit pin verification.
| Property and unit | Published value and conditions | Sources and dates |
|---|---|---|
| Firmware base & current version (Klipper fork / Marlin fork / proprietary) | RatOS, Rat Rig's Klipper distribution | 1 source
|
| Property and unit | Published value and conditions | Sources and dates |
|---|---|---|
| Assembly level & time from unbox to first print | Self-assembly kit; Raspberry Pi and enclosure panels sourced separately | 1 source
|
This guide presents the catalog’s sourced record for this exact model. Source dates belong to each reference; a page update does not mean every specification has been rechecked.
Prices are dated listing snapshots, with configuration, regional and sale conditions. They are not current offers. Unknown values remain unfilled.
Firmware, variants and available accessories can change. Read the original reference before making a purchase or planning a process.
Firmware, modifications and troubleshooting links are checked against the model and stated hardware or firmware revision. A creator’s compatibility claim is not a fit test by this site. Official troubleshooting describes a diagnostic route; individual reports do not establish a failure rate.
3D Printing Info