Cylinder Bore Measurement Tool Identification

The question asks to identify the correct tool for measuring the diameter of a cylinder bore. Accurate measurement is crucial in mechanical applications, especially in engine rebuilding, to ensure proper fit and function.

Tool Analysis for Cylinder Bore Diameter

Let's analyze the provided options to determine the appropriate gauge:

• Taper plug gauge: This gauge is primarily used to check the size and taper of holes or shafts. It is not designed for precise measurement of a cylinder bore's diameter.
• Barometer: A barometer measures atmospheric pressure and is unrelated to measuring mechanical dimensions like bore diameter.
• Telescopic gauge: This is a precision measuring tool specifically designed to measure the internal diameter of bores, slots, and recesses. It consists of spring-loaded plungers that can be locked in place, allowing the measurement to be transferred to a micrometer or caliper for an accurate reading. This makes it ideal for measuring cylinder bore diameter.
• Screw pitch gauge: This tool is used exclusively for measuring the pitch (distance between threads) of screw threads and has no application in measuring bore diameters.

Conclusion on Gauge Selection

Based on the function of each tool, the telescopic gauge is the specialized instrument used for accurately measuring the diameter of a cylinder bore.