The taper bore of a tapered bore bearing is typically how steep?

The taper bore of a tapered bore bearing being typically 1 in 12 is based on standard engineering practices for this type of bearing. A 1 in 12 taper means that for every 12 units of length along the bore, the diameter decreases by 1 unit. This moderate taper angle provides a good balance between ease of assembly and the effective holding power when the bearing is pressed onto a shaft.

Using this taper ratio facilitates proper alignment and ensures that the bearing can be securely mounted without excessive stress on the material. It also allows for a greater surface contact area which is crucial for load distribution and enhancing the bearing life. Choosing a taper that is too steep could complicate installation and affect the stability and performance of the bearing in operation.

While other taper angles (such as those found in other choices) do exist for different specific applications or types of bearings, 1 in 12 is the most commonly referenced standard for tapered bore bearings in general use. This is why it is the correct answer in this context.