Bending Strap — Lutherie Encyclopedia

Bending StrapType: toolA thin spring-steel strap with handles that supports wood during bending, preventing cracking and blowouts.## Description A bending strap is a thin strip of spring steel, usually 0.2mm to 0.5mm thick and about 75mm wide, fitted with wooden or metal handles at each end. The strap is placed against the outside surface of the wood being bent, sandwiching it between the strap and the bending iron or form. The steel distributes tension forces across the outer face of the wood, which is where cracks would otherwise initiate during bending. Some straps include an adjustable end-stop to set the side length. ## Use in Lutherie When bending guitar sides over a bending iron, the wood experiences compression on the inside face and tension on the outside face. Without a bending strap, the tension forces can exceed the wood's strength and cause cracks, especially in brittle species like rosewood, maple, or koa. The strap is essential for bending sides thicker than 2mm and for any species prone to cracking. It is positioned over the wet side blank, and both the strap and wood are pressed together against the heated iron while the luthier forms the curve. ## Selection Guide A good bending strap should be made from tempered spring steel that holds its flat shape. The width should match or slightly exceed the width of the guitar sides being bent, typically 75mm to 100mm. Handles should be securely attached and comfortable to grip, as the bending process requires sustained hand pressure. Stew-Mac, LMI, and Summit offer ready-made straps for 25 to 50 dollars. Many luthiers make their own from spring…