9 Round to Round/Round Taper on a Pitch

  1. Draw a complete elevation view. Keep in mind that any plan view would need to be projected from the elevation to keep the end on a pitch to correct shape, it will not be viewed as the original size or shape. Because of the pitch, in the plan view it will be viewed as an ellipse.

 

  1. Draw profiles at each end.

 

 

  1. Draw in all element lines and label the elevation view. It is recommended to zig-zag up and down to number this fitting.

 

 

  1. Find the TL of line 1-2. Since the outside edges are true length in an elevation view, start the pattern by drawing the true length of line 1-2 on a vertical plane. Similar to plan view triangulation a round to round should always be started from a vertical line.

 

  1. These instructions will cover 1 side of the fitting, but as you work through, work both sides symmetrically.

 

  1. Find the TL of line 2-3. To find the TL of line 2-3, swing element line 2-3 from point 3 and transfer it to the top line of the elevation view. The top line may have to be extended for the element line to fit.

 

 

  1. Next we will find the “difference in profile” for this line. Since there is no profile height at point 2, the full distance of point 3 is the difference.

 

  1. The TL of line 2-3 will be the hypotenuse of the triangle formed by profile 3 and element line 2-3 along the top. From the difference in profile to the length of line 2-3 on the top line.

 

 

  1. Pick up the TL of line 2-3 and swing it from point 2 on the pattern.

 

 

  1. Pick up step-off 1-3 from the elevation view and swing it from point 1 on the pattern. This creates point 3.

 

 

  1. Find the TL of line 3-4. Swing element line 3-4 from point 4 and transfer it to the baseline of the elevation view.

 

  1. Take profile line 3 and transfer it to profile line 4, make sure to locate it from the outside towards the inside.

 

  1. Pick up the TL of line 3-4 and swing it from point 3 on the pattern.

 

  1. Pick up step-off 2-4 from the elevation view and swing it from point 2 on the pattern. This creates point 4.

 

  1. Find the TL of line 4-5. Swing element line 4-5 from point 4 and transfer it to the baseline of the elevation view.

 

  1. Take profile line 5 and transfer it to profile line 4, make sure to locate it from the outside towards the inside.

 

  1. Pick up the TL of line 4-5 and swing it from point 4 on the pattern.

 

  1. Pick up step-off 3-5 from the elevation view and swing it from point 3 on the pattern. This creates point 5.

 

  1. Find the TL of line 5-6. Swing element line 5-6 from point 6 and transfer it to the baseline of the elevation view.

 

  1. Take profile line 5 and transfer it to profile line 6, make sure to locate it from the outside towards the inside.

 

  1. Pick up the TL of line 5-6 and swing it from point 5 on the pattern.

 

  1. Pick up step-off 4-6 from the elevation view and swing it from point 4 on the pattern. This creates point 6.

 

  1. Repeat this process for points 7-12.

  1. Find the TL of line 12-13, swing element line 12-13 from point 12 and transfer it to the baseline of the elevation view.

 

  1. Because there is no profile line at 13, we will use the full height of the profile line at point 12.

 

  1. Pick up the TL of line 12-13 and swing it from point 12 on the pattern.

 

  1. Pick up step-off 11-13 from the elevation view and swing it from point 2 on the pattern. This creates point 13.

 

  1. Find the TL of line 13-14. Because we are back to the outside edge, this line is true length in the elevation view.

 

  1. Pick up the TL of line 13-14 and swing it from point 13 on the pattern.

 

 

  1. Pick up step-off 12-14 from the elevation view and swing it from point 12 on the pattern. This creates point 14 and finishes the pattern.

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Pattern Development: Sheet Metal Level 2 Copyright © by bcoey. All Rights Reserved.

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