Triangulation
26 Off-Centre Square to Round
The only difference with this fitting is a few more element line lengths than an on-centre, the process is exactly the same.
- Draw a full plan view complete with all element lines and labeling. Choose a line of symmetry to place the seam so you only need to make 1 pattern. Label one half of the plan view, the round end with numbers and the square end with letters.
- Create a TLD and label it
- Draw a baseline equal to line A-B.
- Pick up the true length of line A-4 and swing it from point A.
- Next, pick up true length of line B-4 and swing it from point B. Where it crosses the first arc, becomes point 4.
- Pick up a step-off from the plan view and swing it from point 4. Unlike an on-centre square to round, this fitting needs to be developed one side at a time. Complete one side, then go back to finish the other side.
- Pick up the true length of line A-3 and swing it from point A.
- Pick a step-off and swing it from point 3.
- Pick up the true length of line A-2 and swing it from point A.
- Pick up a step-off and swing it from 2.
- Pick up the true length of line A-1 and swing it from point A.
- Pick up the true length of line D-1 and swing it from 1.
- Pick up line A-D from the plan view (remember that letter to letter is true length) and swing it from point A. Remember that point D should be 90°. If it not, go back and check your work.
- Now, go back to point 4 and work the pattern to the other side, completing it at point C. Notice in this example, line C-7 has no length in the plan view, it is a dot. The true length is the vertical height. Zero plan length put 90 deg to the vertical height, will have no change to the vertical height.
- Draw in the all the element lines and outside edges, using a flexible curve for the round end.
definition
looking down at something, a “birds eye view”, “floor plan” (2D)
a line representing an edge or bend
a 90° corner in that we use to find the actual length of a line
a dimension or line that is not distorted by the view
a line/plane straight up and down, vertically level (plumb)