CNC Piston for Short Stroke 12T, nylon GF30%

CNC piston for Short Stroke 12T made of Nylon GF30%

A specially extended, reinforced and significantly lightened piston designed for assemblies Short-Stroked to 12 teeth. The piston is optimized for RetroArms gearboxes, but can be used also in standard gearboxes. Before final assembly, it is necessary to check if the piston can be cocked fully by the 12T sector gear. This piston differs from the standard piston in that it has a longer body and at the same time adjusted dimensions of the guide rails ensuring less leverage during a short stroke of the piston.

The rear part is significantly reinforced to withstand the forces created by the use of strong springs in TSG, DSG and SS assemblies (reach force often around 19 kg) in combination with rapid load changes due to high cadences, often even 60 RPS. It is this combination and cadence, together with the forces of ordinary pistons, that break out the rear part of the piston and shoot the piston rack into the rear part of the gearbox.

The body of the piston is made by CNC milling from Nylon with the addition of 30% glass fibers. This material has very good properties, in particular it is resistant to wear, it can withstand high temperatures and pressure, it tolerates the action of aggressive oils very well, it is resistant to breakage and it is also light. We also produce pressed variants of pistons from the same material.

The Nylon material used is resistant to oils and despite the fact that it is not absolutely necessary to lubricate the guide grooves of the piston body, we have integrated lubrication pockets at the point of contact between the piston and the gearbox.

Despite the robust extended body, it was possible to maintain a relatively low weight, which is very important for fast builds, namely 15.8 g. We do not recommend enlarging the relief holes due to possible damage to the structure. It is possible that the weight of the piston will vary due to moisture absorption of the material. However, we strongly do not recommend drying the piston, soaking in moisture significantly increases the strength of the material.

The piston rack is made of high quality spring steel by CNC milling. The material used is flexible, and at the same time, thanks to the heat treatment, it is also hard, resistant to wear and tear. Despite the fact that it is not necessary to glue the piston rack, some customers glue it (in that case we recommend a two-component epoxy glue) and for this very reason we leave the racks raw (without surface treatment that carries an oil layer) after heat treatment, therefore they are no longer black , but dark gray and may have various colored spots on them. Before installation, it is recommended to lubricate the piston rack, ideally with silicone vaseline.

This piston has 12 teeth and is therefore suitable for use with e.g. PandoRA gears 13:1 SS12T.