Eccentric elbow, manual lofting method.

) First draw the side projection of the elbow according to the actual size. Include seam lines.

2

) Divide each closed wireframe graph into independent graphs with lines.

(You can cut it or draw it separately.

three

) take a mode,

Draw on another piece of paper (the center line is vertical), and draw two horizontal lines parallel up and down along the height of the pattern.

Line, and perpendicular to the center line, the length is exactly the circumference of the pattern diameter.

(closed rectangle)

four

)

Bisect that vertical direction of the pattern,

And mark it,

Then draw these bisectors vertically on the unfolded rectangle just drawn.

In shape, note that the points on the expanded graph must correspond to the points on the projected graph.

five

)

Divide the diagonal on the pattern into equal parts along the horizontal direction.

And parallel to the unfolded pattern,

And correspond to the corresponding points.

spread

The smooth connection of the intersection points obtained on the sample is an expanded curve. The denser the bisection, the more accurate the curve.

six

) release bite amount, and thickness treatment.