that will expand to hold the item. A third type of mandrel is that which is used to hold circular saw blades, buffing wheels (used for polishing), and sanding discs onto drills, circular saws, and similar power tools. A mandrel of this type generally consists of a cylinder, threaded on one end, with a washer brazed onto the threaded end and an accompanying screw and second washer used to clamp the circular saw blade, sanding media, or other rotary tool onto the mandrel. While most mandrels are driven by direct connection to an electric motor or engine, other mandrels are driven by attachment to a bearing-supported, pulley-driven shaft. In Jewellery A 'triblet' is a type of mandrel found in jewelry manufacturing that is not inserted into or held by a machine. Jewelry mandrels typically come in a variety of sizes and shapes, raging from small tapered metal rods (ring mandrels) to free-standing metal cones (used for making bracelets). Unlike with mechanical mandrels, the process is performed by hand. When shaping a ring or bangle with a triblet, it is typical to bend and solder the metal into a rough loop, then place it over the thinner end of the mandrel. Once done, the next step is to strike it in a downward motion with a hammer to push it towards the wider end. This forces the metal to adopt a true ring-shape. Triblets with measurements cut into them (called 'ring size sticks') can also be used as a quick way of measuring the final size of a ring. A triblet can also be used to make a ring slightly bigger by gently tapping it in order to force it down the cone - thus stretching the metal. Triblets are also used to repair squashed or damaged rings. In Music A type of mandrel is also used in making reeds for double reed instruments such as the bassoon or oboe. Uses Mandrels are also used in industrial composite fabrication such as in filament winding. During the manufacturing process, resin-impregnated filaments are wound around a mandrel to create a composite material structure or part. The structure is cured and the mandrel is removed. One problem with this type of process is that the mandrel can be very difficult to remove once the part has been cured. As a result, engineers have created a new type of mandrel that has the ability to