1 Drop Elbow
- Draw an elevation view of the flat radius throat radius heel (RTRH) cheek.
- Bisect the heel and throat.
- Label the elevation view, starting from A-B and ending with E-F.
- Draw in element lines connecting 4 triangles as shown.
- At each point, we want to sub-label with the amount of drop at that point. So both A and B are 0%, C and D are 50% of the drop and E and F are the 100% of the drop. Label these points as the actual number (inches) of drop at each point.
- Create a True Length Diagram (TLD) with a horizontal leg of arbitrary length and the vertical equal to the 50% drop measurement. The true length of lines will come from the hypotenuse of the triangle created between the half (2″) drop and the line length put on the horizontal leg of the TLD
- Start the pattern with baseline A-B, which is a true length in the elevation view.
- Pick up line A-C and put it on the horizontal leg of the TLD. Pick up the TL and swing it from point A.
- Place line B-C into the TLD. Pick up the TL and swing it from point B. This has completed point C.
- Take line B-D and put it into the TLD. Pick up the true length and swing it from point B.
- Take line C-D from the elevation view, (it is a true length) and swing it from point C. Notice our labeling, when we go from the same sub-labeling number, it is a true length, when we go from 0%-50% or 50% to 100% we must put that line into the TLD. Having the same number tells us that line is flat and different numbers tell us that line is sloping.
- Continue to develop triangles, following the labeling.
- Once all 4 triangles have been developed, we need to now create arcs for the heel and throat. We do this by using a geometric technique from level 1, an arc through 3 points. Refer to that chapter if you need a refresher. https://opentextbc.ca/patterndevelopment/chapter/draw-an-arc-through-3-points/
- Add on any seams or allowances like Pittsburgh and S &D.