Descrizione
CNC Gearbox V2 (8mm) – QSC
CNC gearbox V2 is intended to be used with airsoft replicas of AR15 (M4), M16, MP5 and other rifles with V2 gearboxes. Our gearbox is manufactured from a single block of aviation grade duralumin EN AW 7075 T651, which has greater tensile strength (590 MPa) than standard structural steel (390 MPa). Thanks to this material our gearbox shell has several times longer lifespan than standard zinc-alloy gearbox shells. Our gearbox shells are manufactured on precise CNC machines directly in our company in the Czech Republic (EUROPE).
The number in the brackets (e.g. (8mm)) describes the diameter of the holes for bushings / bearings.
The gearbox is equipped with Quick Spring change (QSC) system, thanks to which you can remove the spring without the need of disassembling the gearbox. With this solution it is necessary to secure the spring guide with a screw, which is done by buffer tube screw as standard, or you can use QSC screw if securing with buffer tube screw is not possible / desired. If you leave the spring guide unsecured, the spring will twist with compression, misalign the spring guide and cause gearbox jam with damage to the piston, gears, motor and gearbox shell.
CNC gearbox is possible to install into airsoft replicas of Tokyo Marui standard and is possible to be fitted with components of Tokyo Marui standard. While installing the inner parts into the gearbox, and the gearbox into the gun, never use brute force. For tightening the screws use max moment 1.2 Nm, or the threads will be stripped. If you want to be certain that the screws won’t get loose, threadlock could be used.
Spring of any strength can be installed into our gearbox.
Installation of the inner parts as well as installation of the shell into the gun can be tricky and requires professional knowledge, experience and skill. Because of plethora of different manufactures which are copying from each other and rounding the dimensions of components, there are no standards in airsoft (such as EN, ISO, etc.). This is why our gearbox shell can be plug-and-play in some replicas but struggle to install in others. We did our best to come as close as possible to TM original while improving the shell with little features, such as tongue for wires under pinion gear, little windows for easier gears height adjustment, set screws on the side of the shell for gearbox alignment etc.
Little features for QoL improvements:
All little springs (trigger, safety, AR latch, tappet plate) are always held in some kind of notch, mitigating their tendency to pop off, especially while disassembling
Window for AoE check
Bearing holes are smaller by .02 mm in diameter, to better secure the bearing in place. Holes are also equipped with ANTIROT pockets for glue / ANTIROT bushings. For easier bearings installation you can download, and 3D print our tool.
Wire routes are enlarged
Tongue for wires under pinion gear
All threads are formed (threads are stronger)
Halves of shell are centered by tabs around the gearbox
Window to disengage AR latch
Even more reinforced area around cylinder head
Changelog
What is new in the 2025 version
Pinion-to-Bevel gear meshing reviewed. It took us some time, but after lots and lots of thinking, measuring and testing we slightly repositioned and realigned the motor tower hole and optimized bearing holes positions. Sector gear hole did not move, but spur and bevel gear holes are moved by orders of hundreds of millimeters away from each other. This change ensures better compatibility with gears of different manufacturers. Hole for the motor tower (which was moved almost by 0.1 mm), is now better aligned with the bevel gear axis while maintaining 118° angle as before.
Longer nozzle stroke. We allowed tappet plate to move more forward by 0.3 mm, which allows for shorter nozzles to be used for more reliable feeding, or nozzles with same length to have better air-seal
Improved Cylinder housing. Redesigned cylinder housing, so that cylinder sits on 8 support tabs instead of full-length rails and thus ensuring better compatibility with more manufacturers and easier installation and tuning.
Improved details around bevel gear to support bigger wires.
Improved bushing/bearing holes. We know that most of you like to glue bushings or bearings in place, so we prepared “glue pockets”. With those you can either glue standard bearings/bushings, or you can use our new ANTIROT bushings which click right into those pockets. Distinctive detailing of our Gearbox. Because you want not only fully working gearbox, but also nice and 100% finished product.
Enlarged radius at the front of the gearbox. It means that now it is tougher, and more resistible against cracking.
Redesigned piston rail. For longer gearbox life.
Redesigned rails for selector plate. Compatibility with more manufacturers.
Piston position windows.
Redesigned space around sector gear. Compatibility with more manufacturers and more gear ratios.
More wire routing optimization. Longer wire guide rails which are now also completely shielding path for ambidextrous fire selector.
Added tab for COMPRING anti-reversal latch
Package contains: CNC gearbox shell, QSC spring guide, screws set.
CNC gearbox V2 designed for airsoft replicas AR15 (M4), M16 and other ones with V2 gearbox. This gearbox is manufactured from one solid block of aircraft aluminum (Dural) EN AW 7075 T651, which has higher strength (590MPa), than common construction steel (390MPa). Because of used material, our gearboxes have the best durability and resilience than common zinc-aluminum gearboxes. We are manufacturing these gearboxes on our precise CNC milling machines in our factory. Detail in bracket (8mm) means diameter for bushings/bearings.
Package includes: CNC Gearbox V2 (8mm) – QSC in chosen color, set of screws and QSC spring guide.
We made some useful improvements into our CNC gearboxes V2:
Spring holders have grooves, so the springs for tapped plate and trigger switch will not jump off.
Added groove for safety lever, so it will hold during installation.
Added groove for trigger spring, for better fitting.
AOE control hole.
Sockets for bushings/bearings have smaller diameter about -0,02mm (7,98mm), for non-overturning the bushings during installation. The socket edges are cutted down for better installation.
We enhanced grooves for wiring for 1mm, you can now use wirings with 2,5mm diameter.
Added protecting edge for wiring against the motor.
All threads are now shaped instead of cutted for better strength.
Both of the gearbox parts are centered by milled grooves and edges.
Added hole for releasing anti-reverse latch.
For better durability, we added more material around cylinder head part of the gearbox, this was the most critical part and we added 100% more material where is huge radius.
Added groove for anti-reversal latch spring, so it will not jump off.
Outer edges are now cutted off.
You can find what type of sockets gearbox have on the outside part of the gearbox (8mm or 9mm).
RetroArms gearbox has quick spring change system QSC, where you can put out whole spring guide with hex key and change the spring without need of opening the gearbox. In this solution, you need to secure spring guide with screw, commonly with AR 15 (M4) replicas, it is by stock screw. In situations where you have folding stocks or no stock at all, you have to secure the spring guide with QSC screw. Otherwise there could be situation, where the spring guide will stuck with the spring. This is because the spring guide is not fixed in the gearbox but has will for easy removing with hex key.
Space for trigger switch is designed for compatibility with trigger switches, trigger units from common manufacturers for example: Gate, etc.
CNC gearbox V2 has protective anodizing, even when it is problematic to anodize aluminum EN AW 7075 T651 (Dural), because of its high strength and hardness. If we did not anodize products from this material, there is huge risk of corrosion (huge gray spots with rotten look).
CNC gearbox can be installed only in airsoft replicas with Tokyo Marui compatible standard. That means even the inner parts. Do not use rude force during installation. Use only 1Nm tightening moment on screws, otherwise the screws will overturn in heads. There is no need of tightening screws with rude force, if you want to be sure that screws will sit perfectly, use thread glue or thread color.
You can use in our CNC gearbox any spring of your choice, but be aware that stronger springs will result in lower durability.
!! do not use MAXX cylinder head !!
Installation of the inner parts and gearbox requires professional knowledge, experience and skills. There are a lot of airsoft manufacturers on the market and every one of them create their own sizes, there are no standards like engineering ISO in airsoft. This is the main problem with a lot of inner and outer parts from different manufacturers which can be same product, but with different dimensions. We recommend using only parts from manufacturers with Tokyo Marui compatible parts, where should not be a problem with compatibility with our CNC gearbox.
