GRA 30 ring gauges are designed to check tapered shaft seats when mounting cylindrical roller bearings with a tapered bore in precision applications. They are primarily used to determine the position of the tapered seat relative to a reference surface on the shaft, but can also be used to check whether the centreline of the tapered seat is at right angles to a reference surface on the shaft.

• Used for checking tapered seats
• Intended for a particular bearing size
• Useful also for other than precision applications