connection primary shaft - clutch plate

The connection between these two parts needs a radical fixation, but a axial freedom, but still be able to translate the power from one part to the other.

A good solution is a splined shaft.

It will be a 21x24 splined shaft

the properties: z= 34 (the last unvisible column)

more info: tabellenboek voor metaaltechniek (E31 - p 212)

radius primary shaft

Another imporant part of the clutch is the primary shaft. It's the link between clutch and gearbox.

theoretical the torque produced by the motor is the same torque on the disc plate and the same as on the primary shaft.

calculation:
d= 11,65mm

the real situation: 24 mm

or there is something wrong in the calculations (probably) or there are some properties of the gearbox that influence the radius.