Butterfly joint¶

from woodwright.examples import joints

design = joints.butterfly_joint(length=750)

slab  600 x 200 x 30 mm  oak, 2 pieces: slab_1, slab_2
      - butterfly mortise 90 x 45 mm, waist 15, 8 deep, in top_face, 150 from left_end, 0 from back_edge, across the joint with slab_2
      - butterfly mortise 90 x 45 mm, waist 15, 8 deep, in top_face, 300 from left_end, 0 from back_edge, across the joint with slab_2
      - butterfly mortise 90 x 45 mm, waist 15, 8 deep, in top_face, 450 from left_end, 0 from back_edge, across the joint with slab_2
key   90 x 45 x 8 mm  walnut, 3 pieces: key_1, key_2, key_3
      - shaped to a butterfly, waist 15 mm

def butterfly_joint(length: float = 600, width: float = 200, stock: Stock = THICK_OAK) -> Assembly:
    """Two slabs butted edge to edge, held by three butterfly keys across
    the joint (as in a live-edge table top), inlaid flush into the top faces,
    half of each key in each slab."""
    asm = Assembly("butterfly_joint")
    a = asm.add(Board("slab_1", stock, length=length, width=width))
    b = asm.add(Board("slab_2", stock, length=length, width=width))
    asm.join(Butt(a.back_edge, b.front_edge))
    for i in range(3):
        key = asm.add(Board(f"key_{i + 1}", BUTTERFLY_WALNUT, length=90, width=45))
        at = {a.left_end: length * (i + 1) / 4, a.back_edge: 0}
        asm.join(Butterfly(a.top_face, key, at=at, other=b.top_face))
    return asm