Bore gauges, also known as bore micrometers or internal micrometers, are specialized measuring instruments used to measure the diameter and depth of holes, bores, cylinders, or other internal cylindrical features. They are commonly used in industries such as machining, manufacturing, automotive, and aerospace for precision measurements. Bore gauges provide accurate and reliable measurements of internal dimensions. Here are the key components and types of bore gauges:

Components of Bore Gauges:

1.     Measuring Head: The measuring head of a bore gauge consists of two or three contact points or anvils that expand or retract to fit the internal diameter of the bore being measured. The contact points make direct contact with the bore surface to provide an accurate measurement.

2.     Measuring Plunger: The measuring plunger is connected to the measuring head and moves in response to the expansion or retraction of the contact points. It is typically attached to a spindle that extends outside the bore and interfaces with the measuring instrument.

3.     Measuring Instrument: Bore gauges are often used in conjunction with measuring instruments for reading and interpreting the measurements. This can include dial indicators, digital displays, or micrometer heads.

Types of Bore Gauges:

1.     Two-Point Bore Gauges: Two-point bore gauges, also known as two-point internal micrometers, have two contact points that expand or retract to measure the internal diameter of the bore. They are commonly used for general-purpose measurements and provide reliable and repeatable results.

2.     Three-Point Bore Gauges: Three-point bore gauges, also known as three-point internal micrometers or three-ball bore gauges, have three equally spaced contact points that expand or retract to measure the internal diameter of the bore. The three-point design provides self-centering and ensures accurate measurements, even in cases where the bore may not be perfectly round.

3.     Pistol Grip Bore Gauges: Pistol grip bore gauges have a pistol-shaped handle that allows for easy gripping and operation. They often feature a spring-loaded plunger that automatically expands the contact points when the handle is squeezed. Pistol grip bore gauges are convenient for one-handed operation and are commonly used for quick and simple measurements.

4.     Dial Bore Gauges: Dial bore gauges combine a two- or three-point measuring head with a dial indicator for easy reading and precise measurements. The dial indicator provides a direct reading of the bore diameter on a calibrated dial.

5.     Digital Bore Gauges: Digital bore gauges, also known as electronic bore gauges, feature a digital display that provides a direct reading of the bore diameter. They are easy to read and offer high accuracy. Digital bore gauges often have additional features such as data output, memory storage, and tolerance settings.

Bore gauges are available in various sizes and measuring ranges to accommodate different bore diameters. They are typically used in conjunction with a telescopic gauge handle or an extension rod to reach deep or hard-to-access bores.

Proper care and handling of bore gauges are important to maintain their accuracy. Regular cleaning, lubrication, and calibration are necessary to ensure reliable and precise measurements.