Boning is the skeleton of a corset. Understanding the types, their placement, and how to work with them is fundamental to corset construction.
Flat Steel Bones
Flat steel bones are rigid in all directions — they resist bending along their length and resist twisting. They are placed at center front (flanking the busk on each side) and at center back (flanking the grommets). These positions require rigidity — the front must not fold forward, the back must not collapse. Standard widths: 6mm and 8mm. Standard gauges: 0.5mm (lighter) and 0.7mm (heavier duty). For a first corset, 8mm flat steel at center front and back is typical.
Spiral Steel Bones
Spiral steel bones are made from a coiled wire and can flex side-to-side while maintaining length. They are placed on curved seam lines — the side panels, the curved areas above the hips. These positions require flexibility because the seam curves and the body's shape requires the bone to follow a curve during wear. Spiral bones in the same position as flat bones would cause significant discomfort — they would resist the curve and press against the body. Standard widths: 6mm and 8mm, matching flat bone widths.
Boning Placement Strategy
A basic corset boning plan: flat bones at center front flanking busk (2 pairs), flat bones at center back flanking grommets (1 pair), spiral bones at all other seams and positions. More elaborate construction adds additional bones between seams for smoother shaping. The minimum for a functional steel-boned corset is 8–10 bones; a well-constructed corset typically has 16–24. More bones generally means smoother shaping and better load distribution.
Cutting and Tipping Bones
Steel bones must be cut to the correct length (bone channel length minus a small allowance for movement) and tipped with metal or plastic tips to prevent them from poking through the fabric. Bone wire cutters or tin snips cut steel bones; standard wire cutters tend to crush rather than cut cleanly. Bone tips are available from corset suppliers and are applied with pliers. Untipped bones will work through any fabric over time.
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