Gearbox v. SR25 Extrem QSC (CNC, EN AW 7075 T6, 8mm) - RetroArms
CNC gearbox designed for airsoft weapons type SR25, made of the block of the strongest aircraft duralumin EN AW 7075 T651, which has a higher tensile strength (590MPa) than ordinary structural steel (390MPa). Thanks to the material used, the gearbox has several times longer service life than a conventional zinc collar gearbox. We produce gearboxes on precision CNC machine tools, directly in our factory. The number in parentheses (8mm) indicates the diameter of the bearing bore.
The package contains: CNC gearbox SR25 (8mm) - QSC in the selected color variant, a set of screws and QSC spring guide.
We have incorporated many useful improvements into the CNC gearbox for SR25:
- The spring holders have a notch so that the spring of the feeder arm and the trigger shuttle do not fall.
- Notch for the trigger lock spring to prevent the spring from slipping out during mounting.
- Notch for the trigger spring so that the spring does not slip out during mounting.
- AOE control window.
- The holes for the bearings have a diameter smaller by -0.02 mm (7.98 mm), so that the bearing does not rotate after mounting and the leading edges are chamfered, which simplifies installation.
- We have increased the grooves for the cables by 1 mm, now it is possible to run cables with a cross-section of 2.5 mm without any problems.
- We have added a protrusion as protection against abrasion of cables from the engine neck.
- All threads are now formed, compared to the cut thread they have higher strength.
- Both halves of the gearbox are centered by milled protrusions and grooves.
- We've added a hole through which the reverse latch can be released.
- For even greater service life, we have further strengthened the very critical point on the outside with a gear at the cylinder head, where there is now a large radius and at this point there is 100% more material.
- We have added a notch for the spring of the backstop so that it does not pop out during assembly.
- The outer edges are chamfered.
- On the outside of the gearbox is the diameter of the holes for the bearings (8mm or 9mm).
The gearbox has a quick QSC spring change, thanks to which the spring can be pulled out by simply turning the Allen key with the spring mandrel, without the need to disassemble the gearbox. With this solution it is necessary to secure the spring guide with a screw, for SR25 weapons it is done by tightening the stock screw, or for weapons that have, for example, a folding stock, it is necessary to secure the spring guide with a QSC screw. Otherwise, a situation may occur where the spring conductor gets stuck in the spring. This is due to the quick replacement of the spring, the spring guide is not fixed in the gearbox, but so that it can be pulled out by turning the key.
The space for trigger contacts is adapted so that it is possible to install and use common trigger contacts and processor units from commonly available manufacturers such as Gate, etc.
The CNC gearbox for SR25 has a surface treatment with protective anodizing, because thanks to the properties of duralumin EN AW 7075 T651 it is practically non-anodizable, due to its high hardness and strength compared to normally anodizable aluminum, ordinary anodizing does not penetrate into the material. If this dural is not protected by a surface treatment, there is a high risk of corrosion of aluminum (large gray spots, sometimes with a moldy appearance).
The CNC gearbox can be installed in airsoft weapons in the Tokyo Marui compatible standard. This also applies to internal parts. Never use brute force when installing internal parts or the gearbox itself. When tightening the screws, use a tightening torque of max. 1Nm, otherwise the wrench will turn in the screw head. It is not necessary to tighten the screws "on blood", if you want to be sure that the screws will not loosen, use an optional thread glue or paint.
Any spring force can be installed in the CNC gearbox, but it is necessary to realize that the stronger the spring, the lower the life of the gearbox.
!! do not use MAXX cylinder head !!
Installing internal parts in a gearbox as well as a gearbox in a weapon requires expertise, experience and skill. Thanks to the large number of different manufacturers of airsoft weapons, where each manufacturer "invents" its dimensions and there are no standards in airsoft as we know common from mechanical engineering such as ISO, etc., one type of weapon from several manufacturers can be completely different, both in size and by making internal parts or a mechanism. Therefore, we recommend weapon manufacturers who state Tokyo Marui compatible, where there should be no problem with the compatibility of the CNC gearbox.
producer RetroArms CZ Model variants 6088 Guarantee 24 months Package weight 0.187 kg Diameter of bearings/bushings 8 mm Gearbox material Dural (CNC) For gearbox type SR25 version