# A4T is a Voron toolhead built around 4010 blowers and a 2510 hotend fan

> A4T, Another 4010 Toolhead, is an open hardware Voron front rail toolhead by Armchair Heavy Industries and DW-Tas, with dual 4010 blower fans for part cooling, a 2510 axial fan for hotend cooling, a custom wrist build with Sherpa-Mini spacing, and an assembly that the design brief puts ahead of everything else. It suits a Voron owner who has outgrown the stock toolhead, and the idler compatibility is a hard constraint.

**Armchair-Heavy-Industries/A4T** — [A]nother [4]010 [T]oolhead. A toolhead for Voron front rail printers built around 4010 blower fans, efficient ducts, and easy assembly.

- Repository: https://github.com/Armchair-Heavy-Industries/A4T
- Website: https://github.com/Armchair-Heavy-Industries/A4T
- Stars: 658 · Forks: 54
- Language: Unknown
- License: NOASSERTION
- Published: 2026-10-21 · Updated: 2026-10-21 · Language: en
- Canonical page: https://hysenlabs.com/projects/armchair-heavy-industries-a4t

## A second attempt after reworking someone else's toolhead

A4T stands for Another 4010 Toolhead, and the README opens with the reason it exists. After the last year or two looking after Xol and transforming it into Xol Toolhead, the author thought it was about time to try designing something from scratch. That lineage matters for reading the design brief, because the constraints list reads like a set of problems solved deliberately rather than a set of features chosen. The list is short. Dual 4010 blower fans for part cooling. HF and some UHF hotends, originally designed around Dragon HF with an extender. 2510 hotend cooling with well-directed hotend cooling airflow, with the parenthetical that you cannot beat the amazing 5v Delta 2510. Easy Assembly, marked in bold and set apart from the rest. A custom Wrist Watch BMG mod with Sherpa-Mini spacing, which also works with Sherpa-Mini, with some WWG2 and oribter options now too. Neopixel LEDs with good part lighting from in front of the nozzle. And it is built for the Xol carriage, with the note that it can also work with the Voron Tap or the standard Voron CW2 carriage. The project is by Armchair Heavy Industries together with DW-Tas, who also hosts the Discord and the Ko-fi.

## The repository is CAD files and printed parts

The top level of the repository is exactly what you would expect from an open hardware project and nothing more. There is a 3mf/ directory, a CAD/ directory, an STL/ directory and a docs/ directory, alongside the README, the LICENSE and a .gitignore. There is no firmware, no configuration file, no software of any kind, because the deliverable is a set of files you take to a slicer. The distinction between CAD/ and STL/ is the usual one in this kind of project, with CAD/ holding the editable source and STL/ holding the ready to slice meshes, and 3mf/ holding packaged files that carry their own settings so a print can be reproduced without guessing at layer heights. The docs/ directory holds the images the README links, including the render of the finished toolhead, the wiring diagram for the LED harness and the notes about the Xol carriage, along with a Ko-fi badge. The licence is a custom one that GitHub cannot classify, and the repository badge points to Creative Commons Attribution-NonCommercial-ShareAlike 4.0, so the files are licensable for personal builds but not for commercial redistribution without checking the terms.

The layout you will download is:

```bash
3mf/
CAD/
STL/
docs/
```

## Front idlers are the constraint that decides compatibility

The README devotes a warning section to front idlers, and it is the most practically important thing in the document. A4T can collide with the stock Voron front idlers for older Trident, pre-R2, and current v2.4, when the toolhead is in the front corners of the build area. The consequence is stated exactly, because this can cause issues with the homing sequence when homing X if the toolhead is at the front of the gantry on Y. That is a mechanical interference that shows up as a homing failure rather than as a crash, which is exactly the kind of problem that costs an evening to diagnose. The list of fully compatible idlers is short. clee's BFI, the Beefy Front Idlers. Ramalama2's Front Idlers. And the Voron Trident R2 stock idlers. So the requirement for most people is to swap the idlers, and the README frames that as part of the build rather than as an optional upgrade, with slimmer than stock idlers listed among the ways to avoid build plate area loss along with X and Y gantry joints that are within the same size as the standard Voron 2.4 or Trident joints. A second, more serious warning covers the Cartographer CNC carriage, which is made for StealthBurner rather than for A4T. The probe will sit too low if used with A4T unless you have the tools and skill necessary to remove about 1.8mm off the bottom of the Cartographer CNC carriage mounting points where the probe attaches.

## The bill of materials reads like a build guide

The BOM table is unusually specific for a community design, and each row carries the reasoning rather than just the part. Four M3 square nuts of DIN 562 are specified instead of hex nuts, with the note that square nuts do not spin in a slot the way hex nuts do. The screw list distinguishes top cowling mounting from the toolhead board mount to the back of the Xol carriage, and it separates the extruder mounting screws by wrist variant, with M3 x 16 or M3 x 12 for the WWBMG and Sherpa-Mini respectively and a combination of M3 x 20 and M3 x 16 for the WWG2. There is a specific note about the M3 x 6 screws being needed only for the Xol carriage, because if you use Tap or another Voron carriage you already have longer SHCS where the hotend adapter slots under. Two 4010 blower fans are recommended with a GDStime 12,000 RPM 24v, and the entry carries a hard warning that HoneyBadger 9K 4010 fans are known to be incompatible while the 12K version is OK, with the BERSERKER VINDR line struck through and a note that newer BERSERKER 4010s have an updated design and should be OK. The single 2510 axial fan is a Delta Electronics 15,000 RPM 5v ASB02505SHA-AY6B, and here the entry documents a manufacturing tolerance issue, that GDStime 2510 fans have been measuring as around 10.4mm thick, with the workaround of sinking the hotend fan duct 0.4mm into the print bed with the slicer before printing. Three Neopixel LED PCBs of the same kind as used in Stealthburner, the solder pad version, with a wiring diagram and a note that different cowling types need different wire lengths, plus nine lengths of 28 AWG or 26 AWG wire and a connector with crimps for the harness.

## Hotend choice changes what you have to buy

The hotend row of the BOM is the one place where a design constraint turns into a shopping list. The recommendation is a Dragon HF with a Triangle Lab ZS-MZE-HF, and the alternatives listed are Chube Compact, Dragon UHF or UHF-Mini, and Dragon Ace, which uses the included 3mm spacer, and Dragon Ace with MZE. The pattern across those alternatives is that the mounting differs, and the BOM is specific about it. The design brief itself says HF and some UHF hotends, originally designed around Dragon HF with an extender, so the shape of the heatbreak and the mounting of the shroud are what the printed parts were drawn around. That has an effect on anyone bringing a different hotend to the design, because the toolhead is not a universal mount, and the extruder adapter is tied to the wrist build rather than to the hotend. There is also a note that A4T uses standard length probe modules for the Xol carriage, even with UHF hotends in A4T, which means the probe does not need to be swapped for the shorter modules a UHF hotend would otherwise want.

## Assembly notes for the Xol carriage and Tap

The pre-requisites section is a short list with two supporting notes. A printer that fits either the Xol carriage or a standard Voron CW2 or Tap carriage, with the explicit exclusion of the Cartographer CNC carriage. To avoid build plate area loss, X and Y gantry joints that are within the same size as the standard Voron 2.4 or Trident joints, and slimmer than stock idlers. The Tap path has its own instruction: see Voron Design instructions to install TAP, and if using tap, it is highly recommended to replace M3x50 SHCS with button head screws for better build plate clearance. That last detail connects the Tap advice back to the BOM, where two M3 x 50 SHCS are listed for bottom cowling mounting with the note that they are the same as are in the bottom of Stealthburner, so the button head substitution is a swap within an existing line item rather than a new part. For the Xol carriage there is a pointer to the Xol-Carriage documentation in the Armchair Heavy Industries Xol-Toolhead repository, with a separate note that Monolith Gantry users should go with the Monolith specific Xol-Carriage mod in the Armchair-Usermods repository. The Easy Assembly goal is therefore a claim about the printed parts, and the caveats above are about what you bring to the build, which is the honest reading.

## A family of parts built around the same core

The README positions A4T inside a wider set of the author's designs, and reading those links tells you where the project is going. A4Tv2 is in early development and publicly available at the DW Tas GitHub, which is the successor to the design described here. The Crossbow Filament Cutter and EMU MMU are presented as a way to make A4T part of a complete MMU system, so the toolhead is being designed to work with an automatic filament changer rather than to stand alone. And the origin story connects back to Xol and Xol Toolhead, with the Xol carriage documentation and the Armchair-Usermods repository carrying the earlier work. The repository is not archived, the last push was on 2026-10-18, and there are no GitHub releases, so the commit history on main is the record of what changed and when. For a design that people print rather than install, that is a reasonable arrangement. You take the files in the repository as they stand at a commit you choose, and the git history tells you whether a part changed after your slice files were exported.

## Conclusion

Adopt A4T if you own a Voron 2.4 or Trident with a Xol, CW2 or Tap carriage, you print high speed parts with an HF or UHF hotend, and you are prepared to replace your front idlers and to trim about 1.8mm off a Cartographer CNC carriage if you use one. Do not adopt it on a stock pre-R2 Trident or a current 2.4 with the original idlers, because the README documents the collision and the homing failure it causes. Verify first that your carriage is one of the supported three, that your front idlers are on the compatibility list, that your blower is not one of the known incompatible 9K fans, and that the design files in STL/ and CAD/ match the revision of the documentation you are reading.

## FAQ

### Which printers and carriages does the A4T toolhead fit?

A printer that fits either the Xol carriage, or a standard Voron CW2 or Tap carriage. The Cartographer CNC carriage is explicitly excluded, because the probe sits too low with A4T unless you remove about 1.8mm from the mounting points where the probe attaches.

### Why does A4T collide with my front idlers?

A4T can collide with the stock Voron front idlers for older Trident, pre-R2, and current v2.4, when the toolhead is in the front corners of the build area, which can cause issues with the homing sequence when homing X with the toolhead at the front of the gantry on Y. Fully compatible idlers are clee's BFI, Ramalama2's Front Idlers, and the Voron Trident R2 stock idlers.

### Which cooling fans does the A4T bill of materials specify?

Two 4010 blower fans for part cooling, with a GDStime 12,000 RPM 24v recommended and a warning that HoneyBadger 9K 4010 fans are known to be incompatible while the 12K version is OK, and one 2510 axial fan for hotend cooling, a Delta Electronics 15,000 RPM 5v ASB02505SHA-AY6B. GDStime 2510 fans have measured about 10.4mm thick, so the duct can be sunk 0.4mm into the print bed in the slicer.

### What files do I need to build an A4T toolhead?

The repository carries a 3mf/ directory, a CAD/ directory and an STL/ directory, plus a docs/ directory with the render, the LED wiring diagram and the carriage notes. There is no firmware or configuration, because the deliverable is printed parts and an assembly.

## Sources

- [Armchair-Heavy-Industries/A4T on GitHub](https://github.com/Armchair-Heavy-Industries/A4T)
- [Issues](https://github.com/Armchair-Heavy-Industries/A4T/issues)
- [Project website](https://github.com/Armchair-Heavy-Industries/A4T)
- [README](https://github.com/Armchair-Heavy-Industries/A4T/blob/main/README.md)

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Hysen Labs editorial analysis, written from the project's own repository and release notes. Cite the canonical page: https://hysenlabs.com/projects/armchair-heavy-industries-a4t