Parallel Line Pattern Development

# 19 Round Elbow

For this example we will use a 6″ diameter-6″ throat radius-4pc-90°.

- Use the (# of pcs × 2 − 2) to find the number of . For our example, it is
**4 × 2 − 2 = 6**. Each end piece is made up of 1 and each middle piece is made up of two gores.

- Use the angle of the elbow divided by the number of gores to find the angle. In our case,
**90° ÷ 6 = 15°**. - Now that we know the miter angle is 15°, we can use an end gore and lay it out similar to a “Pipe on a Miter” (see Pipe on a Miter).
- Draw an , complete with the miter line.

- Draw a profile below (see Divide a Circle Into 12 Equal Parts) and label it.
- Project the divisions up into the elevation view.
- Draw the
**elevation view**and divide it into 12 equal parts (see Divide a Line Using a Ruler on an Angle).**Label it to match the elevation view and make sure to start the labeling on centre of the gore. Add any required seam allowances outside of the stretch-out.** - At the points where the cross the miter line, project them into the stretch-out.
- Following the labeling, circle the intersection points on the stretch-out.
**Don’t put a dot over the points, but circle around them.** - Using a flexible curve, join the points to draw in the
**miter line,**completing the**.**

- Draw an , complete with the miter line.
- We now need to finish the calculation for the blank size of the elbow. We already have the
**stretch-out**, but we need the height. This is found by multiplying the seam height by the number of**gores.**For our example, simply measure the**elevation view**and find the height of the**element line**on centre of the**gore**. This should be 2 7/16″.**2 7/16″ × 6 =14 5/8″**. - Now, cut out the blank size.

- Mark the seam height of each gore vertically on the stretch-out.

- To complete the elbow, trace or transfer the first gore pattern onto the blank and cut it out. Then, flip it and trace it for the rest of the gores.
**Do not flip left to right, only up and down and remember that you must leave 2 seam heights (****2 gores)****for the middle pieces. This will allow the seams to be orientated on opposing sides****and****produce the**“fish” pattern.

the number of pieces of a round elbow times 2 then minus 2(# of pcs x 2-2) gives us the number of gores in the elbow

a part of a round elbow which allows us to calculate the miter angle

an intersection of 2 pieces- an irregular cut on the end of something

looking at the front or side of something, to have elevation (height), 2D

a half of a plan view, drawn on the outside of an object

a shape which has been “stretched out”, to take a perimeter and make it straight

a line representing an edge or bend

the shape of the object, still in 2D form