Understanding the Feeler Gauge Tool

A feeler gauge is a tool used to measure small distances or gaps accurately. It consists of a set of thin blades of different thicknesses, typically hinged together in a holder.

Each blade has a specific, marked thickness. Users select one or more blades to find the combination that fits snugly into the gap being measured. The sum of the thicknesses of the blades that fit indicates the size of the gap or clearance.

Purpose of Feeler Gauge Measurement

The primary function of a feeler gauge is to determine the size of a gap between two surfaces. This is particularly important in mechanical and automotive applications where specific clearances are required for proper operation.

Analyzing Feeler Gauge Measurement Options

Let's look at the options provided and consider what a feeler gauge is typically used to measure:

• Width: While a feeler gauge blade has a width, measuring the width of an object is not its main purpose. Tools like rulers, calipers, or measuring tapes are used for measuring width.
• Thickness: A feeler gauge itself is made of blades with defined thicknesses. However, its application is usually to measure the thickness of a space, not the thickness of a solid object or the blade itself in the context of measuring something else.
• Small gaps & clearances: This is the specific purpose of a feeler gauge. It is designed to measure the distance between two components, often called a clearance or a gap. Examples include the gap between a spark plug electrode and the ground strap, or the clearance between valve tappets and camshaft lobes.
• Diameter: Measuring the diameter of round objects like holes or shafts is typically done with tools like calipers (inside or outside) or micrometers. A feeler gauge is not suitable for measuring diameter.

Based on the function and design of the tool, the most accurate description of what a feeler gauge measures is small gaps and clearances.

How to Use a Feeler Gauge for Accurate Gap Measurement

Using a feeler gauge involves selecting blades and inserting them into the gap. Here are the basic steps:

1. Identify the required gap size (e.g., from a service manual).
2. Select a blade or combination of blades from the feeler gauge set that matches the required size.
3. Try to insert the selected blade(s) into the gap.
4. The correct feel should be a slight drag when pulling the blade through the gap. If it fits too loosely, the gap is larger than the blade thickness. If it doesn't fit, the gap is smaller.
5. Adjust the blade thickness until the correct drag is felt to accurately determine the gap size.

Revision Table: Feeler Gauge Measurement Facts

Additional Information on Feeler Gauges

Feeler gauges come in various types, including:

• Straight Blade Feeler Gauges: The most common type, with straight blades.
• Tapered Feeler Gauges: Blades are tapered, useful for measuring gaps that might be easier to access with a taper.
• Wire Feeler Gauges: Used specifically for measuring spark plug gaps, consisting of round wires of precise diameters.

Using the correct feeler gauge and technique is crucial for accurate measurements in precision assembly and maintenance tasks.