What is the typical reasonable diameter of a steel hub as per standard recommendations?

The typical reasonable diameter of a steel hub recommended in design practice is often cited as approximately 1.8 times the diameter of the shaft it is attached to. This ratio is derived from practical considerations of strength, stability, and ease of manufacturing.

A diameter of 1.8D provides a balance between sufficient strength to withstand torque and shear loads without excessive material use. This size ensures that there is ample contact area for secure fastening while also allowing for efficient heat dissipation during operation, which is crucial in many mechanical systems.

Using values greater than this, such as 2D, may lead to unnecessary material costs and weight, while dimensions significantly lower than 1.8D, like 1.55D or 1.20D, could compromise the load-carrying capabilities of the hub, making it less efficient and potentially leading to premature failure under typical working conditions.

Thus, the chosen answer aligns well with industry standards and practices for hub diameters in steel applications.