Airsoft gearbox parts

An airsoft gearbox is a small mechanical air compressor housed in a metal casing and driven by an electric battery. The compressed air is created by cogs driving a piston into a cylinder, producing a short burst of air to propel a plastic bb pellet.

There’s no doubt that airsoft gearbox parts are numerous and appear complicated, but with a little understanding of the mechanics involved even a novice can recognise, repair, upgrade and maintain a gearbox confidently and correctly.

Open up an airsoft gearbox and the first thing you’ll notice is the number of moving parts – and there’s no denying that there’s quite a few. So let’s start looking into each part and its function, starting at the bottom.

At the bottom we’ve got the bevel gear. This is the gear that connects with the motor that comes up through the bottom of the gearbox. As it connects with the motor, the teeth are cut at a 45 degree angle (as the motor’s teeth are) to ensure the maximum surface area and prevent slippage. This angular cut is known as a ‘bevel’, which explains its name!

If you look closely at the bevel gear you’ll also notice a second smaller cog in the middle, which connects with the anti-reversal latch to prevent the motor spinning in the wrong direction between shots and causing damage to the gearbox parts. The anti-reversal latch is a simple straight piece of metal sprung against the casing.

The next in the gearbox parts is the spur gear. This gear is used to bridge the distance between the bevel gear and the piston and specify the correct torque ratio for driving the gears.

Next to the spur gear is the sector gear, which contains two sets of teeth. The first set connects to the spur gear and the second to the piston teeth to drive the piston backwards. You’ll notice that this second set only has half the teeth of the other cogs, allowing the piston to release and fire the compressed air before its picking up again on the next rotation.

On top of the sector gear is a large piece of black plastic with a triangular point pointing downwards. This is the tappet plate, which moves a nozzle on the end of the cylinder to allow bb’s to load in front of it before they’re fired. The plate is also connected to a small spring to move it back into position after each shot.

Below the tappet plate is the trigger which, when pulled, switches on the motor and begins the firing process.

Above the tappet plate is the cylinder and cylinder head – a metal casing which holds the piston and channels the compressed air into the nozzle. The piston is a long piece of plastic that contains a piston head used to form an air tight seal inside the cylinder. The piston also includes teeth along its length, allowing it to be pulled back by the sector gear.

A large spring is then pushed into the piston and braced against the casing to propel it forward when released from the sector gear, pushing air through the nozzle and propelling the bb forward. The spring is kept in place using a spring guide.

Bushings are also housed in the casing to keep the gears in line and ensure they spin freely and with as little resistance as possible. Finally washers are used to align the gears together and further lessen resistance when spinning.

Now that you know the gearbox parts, why not have a look into your own gearbox? There are many great tutorials on how to open / remove airsoft gearbox parts for any gun you have. Alternatively, have a look for second hand airsoft gearbox parts online – there’s always plenty going from old repairs / upgrades and at very affordable prices.

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