The RetroArms 8mm Split Version 2 CNC gearbox is made from highly durable Dural EN AW 7075 T651 aircraft-grade aluminum, which offers superior mechanical strength compared to traditional structural steel. The selected materials make the Retro Arms gearbox an unparalleled alternative to conventional zinc alloy gearboxes.
Split gearbox
The Retro Arms split gearbox refers to a gearbox that is divided into two parts along the center. The upper part houses the piston, cylinder, cylinder head, tappet plate, nozzle, spring, and spring guide. The lower part contains the remaining components, such as the gears, trigger mechanism, and various levers.
The two-part design makes maintenance easier, as it allows, for example, the cylinder assembly to be replaced in an M4-style replica without removing the lower part.
Quick spring change
All Retro Arms CNC gearboxes feature a quick spring change system. This allows the spring to be replaced without disassembling the gearbox, through an opening at the rear. The spring can be changed by gently pressing the spring guide inward and turning it with a hex key.
Compatible nozzle
Retro Arms recommends using a 21.3mm nozzle. Please note that the nozzle length and performance are also affected by the tappet plate angle and the length of the hop-up bucking lips. In some cases, a slightly longer or shorter nozzle may work better than the default length, and the best result can only be determined through testing.
Features:
- QCS quick spring change from the rear of the gearbox
- Split gearbox design
- Hop-up unit attaches to the gearbox
- Grooves in spring retainers to keep tappet plate and contact springs in place
- Additional groove to hold safety components in place during assembly
- Additional groove to hold trigger spring in place during assembly
- AOE (Angle of Engagement) inspection port
- Bearing seats are 0.02mm smaller than nominal bearing size (7.98mm) to prevent movement inside the seat; edges are chamfered for easier installation
- Cable channels designed for 2.5mm wiring
- Edge to protect wiring from the motor shaft
- Gearbox shells aligned with CNC-milled grooves and edges
- Anti-reverse latch release hole to remove tension before disassembly
Package Includes
- Gearbox
- Hop-up unit
- Spring guide
- Screws
Note! Do not use MAXX MODEL cylinder heads or similar parts with Retro Arms CNC gearboxes if they do not transfer impact to the front edge of the gearbox. The pins designed to keep the cylinder head in position should not absorb the piston impact. Using an incompatible cylinder head will damage the gearbox.
Installing internal parts requires experience and skill. There are many airsoft manufacturers on the market, each with its own standards. For this reason, when using parts from different manufacturers, some fitting may be necessary. We recommend using only parts that are directly Tokyo Marui compatible to avoid compatibility issues.
