Using a feeler gauge involves selecting the correct blade size and sliding it into a gap to measure the space between two components.
A feeler gauge is a tool used to measure the gap width between two parts. Its fundamental job is to slide between two components and measure the amount of space between those. While typically associated with small clearances, feeler gauges can also be large, maintaining this core function of measuring the gap by how easily the selected blade slides in.
Here's a breakdown of how to use one effectively:
Steps for Using a Feeler Gauge
- Understand the Goal: Determine the specific gap you need to measure (e.g., valve clearance, spark plug gap, bearing clearance). Know the required specification or range for this gap.
- Select the Right Tool: Feeler gauges come in various types (straight blades, angled blades) and sizes (metric and imperial). Choose a gauge set that includes the range of sizes relevant to your task.
- Prepare the Area: Ensure the gap is clean and free of debris, oil, or grease, which can affect the measurement accuracy.
- Choose a Blade: Start with a blade that is likely slightly smaller than the expected gap.
- Insert the Blade: Gently slide the selected blade into the gap.
- Correct Fit: The blade should slide in with a slight, consistent drag. You should feel some resistance, but it shouldn't require force to push it in.
- Too Small: If the blade goes in too easily with no drag, try the next larger size.
- Too Large: If the blade doesn't fit or requires significant force, try the next smaller size.
- Find the "Go/No-Go" Point (If using multiple blades): Some sets have multiple blades of slightly different sizes. You might use a "go" blade that should fit and a "no-go" blade that should not fit, confirming the gap is within a specified tolerance.
- Read the Measurement: The correct measurement is indicated by the size marked on the largest blade that fits with the correct amount of drag.
- Repeat as Necessary: For critical measurements, repeat the process a couple of times to ensure consistency.
Types of Feeler Gauges
- Straight Blade Sets: The most common type, with multiple blades hinged together.
- Stepped Feeler Gauges: Blades have a step, allowing for a "go/no-go" check with a single insertion.
- Wire Feeler Gauges: Used specifically for measuring spark plug gaps.
- As mentioned in the reference, feeler gauges can also be large for measuring wider gaps, but they still operate on the principle of sliding a blade into the space.
Tips for Accuracy
- Avoid bending the blades unnecessarily, as this can damage them and affect accuracy.
- Hold the feeler gauge blade flat against the surfaces defining the gap.
- Use a consistent amount of force when sliding the blade.
By following these steps, you can accurately measure the clearance between components using a feeler gauge.
