Читать книгу Wood & Steam - Charlie Whinney - Страница 21

This is a compression strap, which is normally a thin piece of steel fixed to the “outer radius side” of the wood before bending, stopping the wood fibers from stretching during the bend. All the straps in this book use 1/32″ (1mm) thick stainless steel that we buy ready-cut from our steel supplier (you normally have to buy a whole or half sheet and they will cut it into your desired-width strips with a guillotine, or you can buy online). Spring steel, mild steel, and galvanized steel are all good too, in thicknesses of up to about ⅛″ (3mm), and thin composite straps of fiberglass or woven stainless steel mesh are good for thinner bends. The purpose of the compression strap is to force the wood fibers to squash and compress during the bend, so materials that can stretch, even a tiny bit, are not suitable. Do not use nylon rachet straps or aluminium as these can stretch. There are several ways to secure the wood into the strap, using wedges, clamps, threaded “adjustable end-stops,” and hydraulic methods. In this book we will be using variations on the wedged compression strap.