Pipe Bend Calculator
Understanding Pipe Bending Calculations
Accurate pipe bending is a critical skill in fabrication, plumbing, and engineering. Incorrect bends can lead to wasted material, improper fits, and structural weaknesses. This calculator helps you determine the key measurements needed for a perfect bend: the Setback, Arc Length, and Gain.
Key Terminology Explained
- Pipe Outside Diameter (OD): The distance across the exterior of the pipe. While not always used in the primary bend formulas, it's essential for selecting the correct die and understanding clearances.
- Bend Angle: The number of degrees you intend to bend the pipe (e.g., 90 degrees for a right angle).
- Centerline Radius (CLR): The distance from the center of the bending die to the centerline of the pipe. This is the most crucial measurement for determining the bend's characteristics.
- Setback: The distance from the point where the bend starts (tangent point) to the apex of the bend's outside angle. You need this measurement to mark where to start the bend. The formula is:
Setback = tan(Bend Angle / 2) * CLR. - Arc Length (Developed Length): The actual length of the pipe material that will be used to form the bend. The formula is:
Arc Length = (Bend Angle * π / 180) * CLR. - Gain: The "shortening" of the pipe that occurs because the material travels along the shorter inside radius of the bend. It's the difference between two setback lengths and the arc length. The formula is:
Gain = (2 * Setback) - Arc Length. Knowing the gain is vital for calculating the total cut length of the pipe.
How to Use the Calculator
- Enter the Pipe Outside Diameter (OD): Input the outer diameter of the pipe you are working with.
- Enter the Bend Angle: Input the desired angle for your bend in degrees (e.g., 45, 90).
- Enter the Centerline Radius (CLR): Input the CLR of your bender's die. This is often stamped on the die itself.
- Click "Calculate Bend": The calculator will provide the Setback, Arc Length, and Gain based on your inputs.
Practical Example
Let's say you need to make a 90-degree bend in a pipe using a bender with a 6-inch Centerline Radius (CLR).
- Pipe OD: 2.375 inches
- Bend Angle: 90 degrees
- Centerline Radius: 6 inches
Using the calculator, you would find:
- Setback: 6.000 inches. You would measure 6 inches from the end of the pipe (or from your previous measurement) and make a mark. This is where the bend will begin.
- Arc Length: 9.425 inches. This is the length of pipe that will be consumed in the bend itself.
- Gain: 2.575 inches. This is the amount of pipe "saved" by bending instead of using two straight pieces joined at a corner. To find the total cut length for a piece with one bend, you would add the two straight leg lengths and then subtract the gain.
Bend Calculation Results
'; resultHTML += '';
resultHTML += '
';
resultHTML += 'Measurements are in the same unit as your inputs (e.g., inches or mm).';
resultDiv.innerHTML = resultHTML;
}
Setback (Marking Point)' + setback.toFixed(3) + '
';
resultHTML += 'Arc Length (Developed Length)' + arcLength.toFixed(3) + '
';
resultHTML += 'Gain (Material Saved)' + gain.toFixed(3) + '
';
resultHTML += '