Measure compression fittings like a pro: the ultimate guide for accuracy
What To Know
- The length of the compression fitting body is the distance between the end of the nut and the end of the body.
- Place the ruler or measuring tape alongside the body and measure the distance from the end of the nut to the end of the body in mm.
- The depth of the compression ring seat is the distance from the end of the body to the bottom of the groove where the compression ring sits.
Compression fittings, ubiquitous in plumbing and fluid systems, offer a secure and leak-free connection. To ensure a perfect fit, it’s crucial to accurately measure their size. This guide will unravel the complexities of measuring compression fitting size, equipping you with the knowledge to make precise measurements and avoid costly mistakes.
Understanding Compression Fitting Terminology
Before delving into measurement techniques, let’s establish a clear understanding of compression fitting terminology:
- Body: The main component that houses the compression ring.
- Compression Ring: A conical-shaped ring that tightens around the tubing to create a seal.
- Nut: A threaded component that tightens the compression ring.
- Ferrule: A metal sleeve that protects the tubing from deformation during tightening.
Measuring the Outside Diameter (OD) of the Tubing
The outside diameter (OD) of the tubing is the first measurement you need to take. This is the diameter of the tubing itself, not including any ferrules or fittings.
1. Use a digital caliper: Position the caliper’s jaws around the tubing and close them until they touch. Read the measurement on the digital display in millimeters (mm).
2. Use a ruler or measuring tape: Wrap a ruler or measuring tape around the tubing and note the measurement where the ends meet. Divide this value by 3.14 (π) to obtain the OD in mm.
Determining the Compression Fitting Size
Once you have the OD of the tubing, you can determine the correct size of compression fitting using one of the following methods:
Method 1: Using a Compression Fitting Size Chart
Compression fitting manufacturers typically provide size charts that indicate the appropriate fitting size for different tubing diameters. Find your tubing OD in the chart and match it with the corresponding fitting size.
Method 2: Calculating the Compression Fitting Size
If a size chart is not available, you can calculate the compression fitting size using this formula:
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Fitting Size = OD of Tubing + 2 x Thickness of Ferrule
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The thickness of the ferrule can be found in the manufacturer’s specifications or measured with a caliper.
Measuring the Thread Size of the Nut
In addition to the body size, you also need to measure the thread size of the nut. This is the diameter and pitch of the threads on the nut that connect it to the body.
1. Use a thread gauge: A thread gauge is a tool with a series of threaded holes of different sizes. Screw the nut into the holes until you find the one that matches the threads. The size of the hole will indicate the thread size.
2. Use a caliper: Measure the diameter of the threads using a caliper. Then, count the number of threads per inch (TPI) by placing the caliper on the threads and counting the number of peaks or valleys within a 1-inch length.
Measuring the Length of the Body
The length of the compression fitting body is the distance between the end of the nut and the end of the body. This measurement is important to ensure that the fitting will fit properly in the space available.
1. Use a ruler or measuring tape: Place the ruler or measuring tape alongside the body and measure the distance from the end of the nut to the end of the body in mm.
Measuring the Depth of the Compression Ring Seat
The depth of the compression ring seat is the distance from the end of the body to the bottom of the groove where the compression ring sits. This measurement is important for determining the proper depth of tightening.
1. Use a depth gauge: A depth gauge is a tool with a graduated rod that can be inserted into the groove. Measure the distance from the end of the body to the bottom of the groove in mm.
Wrapping Up
Measuring compression fitting size accurately is essential for ensuring a secure and leak-free connection. By following the steps outlined in this guide, you can confidently determine the correct size and type of fitting for your application. Remember to always refer to the manufacturer’s specifications for specific measurements and guidelines.
Frequently Asked Questions
Q1. What is the difference between a compression fitting and a compression sleeve?
A1. A compression fitting is a complete assembly that includes a body, nut, and compression ring. A compression sleeve is just the sleeve that goes around the tubing and is used in conjunction with a separate nut and body.
Q2. Can I use different sizes of ferrules with the same compression fitting body?
A2. No, you should always use the ferrule size that is specified for the compression fitting body. Using a different size ferrule can compromise the seal and lead to leaks.
Q3. How tight should I tighten a compression fitting?
A3. Hand-tighten the nut until it is snug, then use a wrench to tighten it an additional 1/4 to 1/2 turn. Overtightening can damage the fitting or tubing.
Q4. What is the recommended torque for a compression fitting?
A4. The recommended torque for a compression fitting varies depending on the size and type of fitting. Refer to the manufacturer’s specifications for specific torque values.
Q5. Can I use compression fittings on PEX tubing?
A5. Yes, compression fittings can be used on PEX tubing, but only with a PEX-specific ferrule. Standard brass ferrules are not suitable for PEX tubing.
