Retro Arms CNC Split Gearbox V2

Retro Arms CNC Split Gearbox V2

Broad Compatibility

The CNC Gearbox V2 is specifically designed for airsoft replicas that use Version 2 (V2) gearboxes, including AR15 (M4), M16, MP5, and others. It supports components built to the Tokyo Marui standard, making it a flexible choice for various custom builds.

High-Strength Material for Superior Durability

Unlike standard zinc-alloy gearbox shells, this gearbox is machined from a solid block of EN AW 7075 T651 aviation-grade duralumin. This material offers a tensile strength of 590 MPa—significantly higher than the 390 MPa typical of structural steel. As a result, the shell lasts several times longer, even under demanding conditions.

Precision Manufacturing in Europe

To ensure the highest quality, we manufacture every gearbox shell on advanced CNC machines at our facility in the Czech Republic (EU). Consequently, each unit meets strict tolerances and consistency standards.

Quick Spring Change (QSC) System for Easy Maintenance

Thanks to the integrated Quick Spring Change (QSC) system, users can replace the spring without fully disassembling the gearbox. The spring guide must be secured either with a buffer tube screw (standard method) or an optional QSC screw. If left unsecured, the guide can rotate under compression, potentially damaging internal components like the piston, gears, motor, and gearbox shell.

Installation Considerations

Although this gearbox is compatible with Tokyo Marui-standard parts, installation may vary due to inconsistent tolerances among different replica manufacturers. Therefore, we recommend installation by experienced users or professionals.

To avoid damage during assembly:

• Never apply excessive force

• Tighten screws to a maximum torque of 1.2 Nm

• Use threadlocker if necessary to keep screws secure

• Feel free to install springs of any strength

Smart Design Enhancements

Structural Reinforcements

• Extra material around the cylinder head increases durability

• Formed threads provide superior strength

• Centering tabs help align both gearbox halves precisely

• Set screws on the sides enable fine-tuning for gearbox alignment

Improved Usability

• Enlarged wire channels allow easier routing

• A dedicated tongue helps guide wires beneath the pinion gear

• Windows make gear height and AoE (angle of engagement) checks quicker

• An additional access point simplifies AR latch disengagement

Bearing & Spring Optimization

• Bearing holes are 0.02 mm smaller to ensure a snug fit

• ANTIROT pockets support glue or bushings for added stability

• A downloadable 3D-printable tool is available to simplify bearing installation

• All small springs (trigger, safety, AR latch, tappet plate) sit securely in notched slots, minimizing the risk of parts popping out during disassembly

Final Thoughts

Because airsoft lacks industry-wide standards like ISO or EN, compatibility may vary. However, we’ve worked hard to closely match the Tokyo Marui original while introducing smart upgrades that improve durability, ease of use, and overall performance.