06. 09. 2018
Since you frequently ask questions about the types and dimensions of our bushings/bearings, we had to write down some basic informations.
The bearings (or bushings) are installed in the gearbox housings of the airsoft gun and they set the position of the gears. The bearings also serves for lowering of friction torque moment on the axis of the gears.
The name of the bearings/bushings version means the diameter under the flange (lower diameter), mostly like 7mm, 8mm and 9mm. Some older airsoft replicas, for example from Tokyo Marui had even 6mm bearings/bushings. The diameter of the bushings or bearings must be the same as the diameter of gearbox housings, this infomation is wrote in the bracket. If you choose gearbox (8mm), it means, that the housings have diameter of the 8mm. It does not mean any version of strength or type.
Picture n.1 - correct measuring of the bearing/bushing diameter. We can see on the picture the bearing with 8mm diameter.
We have two kinds - bushings and bearings.
The bushings are sockets with simple construction. If you manufacture them from hardened steel, they are extremely resilient and they can be use for the most powerful springs. On the other side, they have higher mechanical resistance, but that is balanced with a very long lifetime. There is also no risk of dropping out the balls from bearings. If you choose to use bushings, you have to regularly lubricate them with vaseline on the contanct points of gear axis and bushings.
Picture n.2 - Bushing (on the left side) and Bearing (on the right side).
The bearings have low mechanical resistance and thanks to the balls in the sockets, they are used for high speed gears, but they are also limited for M120 springs. If you want to use bearings in the long term, or on the stronger springs, there is a risk of breaking the sockets and dropping the balls from the bearings. The socket of the bearing is the weakest part of it, because the size of the socket wall is mostly wide about 0,2 - 0,3mm. It is not enough, even if you use high quality steel, this is why we do not recommend to overload bearings. For some time we saw a "ceramic" bearings, be aware from this, because this is only marketing move. The socket of the ceramic bearings is still from steel, but only the balls in the bearings are only ceramic part of it and these are in airsoft replicas useless. Steel balls in bearings are basically indestructible. Bearings does not need a lubrication, because that only attracts sticking dust and sand on the inner part where balls are. Bearings are also in full covered version, but this has a huge disadvantage, the size of ball bearings is much smaller - because of the size of the cover, and these bearings can not withstand the forces in the gearbox.
We offer a lot of versions of the bearings, low profile bushings and standard bushings on our internet store, where you can see our full offer.
The standard height of bushing is 2,5mm or 2,55mm, this height is the same on the all common bearings and bushings.
The low profile bushings solves the problem of jamming plate selector in the V2 gearboxes, where common bushings height jams the plate selector and fire selector, or even breaking them. Low profile bushings are only option, because the manufacturing of low profile bearings is not technologically possible. Even when the height is lower on the low profile bushings, there is no limitation of the lifetime, so you can use our low profile bushing on very strong springs.
In some scenarios, there is possible combination of the bearings and bushings, for example using bearings on the motor gear and using the bushings on the piston and spur gears. It is only individual and these setups depends on every airsoft technicians, where they prefer different kind of solutions. There is of course the need to count with all forces on every bushings or bearings with wanted lifetime.
Picture n.3 + n.4 - heightened plate selector from high bearing, this scenario can occur mostly in the V2 gearbox in AR15. Same scenario could be even during installation standard bushings.
Picture n.5 - damaged plate selector from high bearing, this makes jams on the fire selector and weaks the plate selector, see more above.
Picture n.6 - The difference of height between bushing and bearing (on the left - the low profile bushing, on the right - bearing)
Picture n.7 + n.8 - Installed low profile bushing, the plate selector can now move freely and there is no risk of damage or jamming on the fire selector.
Installation of the bushings or bearings can be managed with special pin tool with right diameter, or with our bearing tool, or with any solid cylinderic tool. Installation process can be start with easy knocking with hammer. If you damage the housing for bearings/bushings in the gearbox, for example overturning or widening the housing, we do not recommend to adjust the bearings/bushings, or wide the housings with levering. In all situations, there would be only worse bearing/bushing housing. The bearings/bushings can be secured with special glue, for example Loctite 601, 603. Choose them by the movement of the bearings/bushings and the size of the housings. In some emergency scenarios, there could be used even superglue. But be aware for bearings, if the glue gets into the socket, where ball bearings are, they would be glued and completely destroyed.
Picture n.9 - installation of bushing with special pin tool.
So we are at the end. We described the common problem with V2 gearboxes in AR15 airsoft replicas. We do not say, that common bearings or bushings are bad, but they are not suitable for some upgrade or usage and there is need of using the low profile ones. With every another replicas, there could be situations, where problem needs a variety combinations of parts and there can not be any universal guide, but only a example, how to solve this problem.
All versions of our bushings, bearings and our bearing tool can be purchased on our internet store.
