change shape and be easily extracted. When heated above a certain temperature, the mandrel becomes elastic and can be manipulated into the desired shape and then cooled to become rigid again in the new shape. It can then be used in the filament winding process. Once the composite part is cured, the mandrel can be reheated until elastic and easily removed from the cured part. These types of mandrels can be used repeatedly. In the production of steel core used for flexible drives, the centre wire upon which the subsequent layers are wound is referred to as a Mandrel. This "centre wire" may itself be composed of either a single wire or layers, depending on the sizing of the finished product. A hole saw usually attaches to a mandrel, the latter being basically a drill bit with threads to secure the saw. History Mandrels are not recent inventions. Metal machining utilizing the spinning process has been recorded as far back as ancient Egyptian times. In metal spinning, a wood or metal spinning mandrel is used, the form of which corresponds with the internal contour of the part to be produced. This method securely clamps the raw material and allows for accurate machining into the desired final form. Since the material is clamped internally, there is no interference to the operator from the lathe/mandrel assembly during production. The traversing mandrel was introduced around 1700, and instantiated the design of a lathe mandrel able to slide axially in its bearings under the control of the operator, so that components having short lengths of thread could be produced, such as screws. The traversing mandrel was primarily employed by clockmakers and ornamental turners during this era. Eventually the device was superseded by a mandrel-driven device called a leadscrew, which uses a train of gears that can be altered as required for the turning application. References External links Historical pictures of mandrels, lathes and leadscrews Expanding The Expanding Mandrel's Usefulness Clamps (tool) Lathes Machine tools Woodworking tools