For a shaft measuring 1" diameter with an RC6 sliding fit, what is the appropriate allowance?

The question is about determining the appropriate allowance for a shaft that has a diameter of 1 inch and is specified to have an RC6 sliding fit. In the context of fits, allowances are important because they define the permissible limits of size for the parts being assembled, influencing how they function together.

With RC6 fits, which are classified as sliding fits, the goal is to allow for easy movement between the mating parts while maintaining appropriate tightness to prevent unwanted motion. The allowance is essentially the intentional difference in size between the parts, ensuring that one can slide freely over the other.

For a sliding fit like RC6, the appropriate allowance would typically be negative, meaning that the shaft is slightly smaller than the hole it fits into. Specifically, for a 1" diameter shaft with an RC6 fit, the correct allowance is -.003 inches. This negative allowance indicates that the maximum material condition of the shaft is less than the corresponding hole size, allowing for a smooth sliding action without the components being too loose.

In summary, the choice of -.003 inches is correct as it provides the necessary clearance for the sliding fit, fitting within the established tolerances for RC6, thus ensuring proper functionality of the assembly while allowing for necessary movement.