Understanding Hole Diameter Measurement Tools

When working with machined parts, accurately checking the diameter of holes is crucial to ensure they meet the required specifications and tolerances. Different tools are used for various types of measurements. The question asks which tool is specifically used for checking the diameters of holes.

Analyzing the Options for Checking Hole Diameters

Let's examine each provided option and its primary function:

• Plug gauge: A plug gauge is a cylindrical or pin-shaped gauge used to check the diameter of a hole. Go/No-Go plug gauges are common, where one end (Go) must fit into the hole, and the other end (No-Go) must not fit, indicating the hole diameter is within the acceptable tolerance range. This tool is specifically designed for checking hole diameters.
• Standard screw pitch gauge: This gauge is used to measure the pitch (distance between threads) of a screw thread. It has several blades, each with a specific thread form and pitch, which are matched against the screw thread to determine its pitch. It is not used for checking hole diameters.
• Fillet gauge: Also known as a radius gauge, a fillet gauge is used to measure the radius of a fillet or curve. It consists of a set of blades with different radii, which are used to match the fillet or curve to determine its size. It is not used for checking hole diameters.
• Slip gauge: Slip gauges, or gauge blocks, are precision ground and lapped steel or ceramic blocks manufactured to very accurate lengths. They are used as standards for calibrating measuring instruments, setting up machine tools, or checking the accuracy of other gauges. While they are fundamental length standards, they are not directly used to check the diameter of a hole in the same way a plug gauge is.

Determining the Correct Tool for Checking Hole Diameters

Based on the functions of the different gauges, the tool specifically designed for checking the diameter of holes is the plug gauge.

Therefore, to check the diameter of a hole, a plug gauge is the appropriate tool.

Revision Table: Gauges for Measurement

Additional Information on Plug Gauges

Plug gauges are essential tools in manufacturing quality control. They are typically made from hardened steel or carbide for durability. Go/No-Go plug gauges are a form of limit gauge, used to check if a dimension is within its upper and lower tolerance limits without providing an exact measurement value.

For precise measurement of hole diameters, tools like inside micrometers or bore gauges are used, which provide an actual measurement reading rather than just a tolerance check like a plug gauge.