Mandrels or arbors are tool components that are used to grip or clamp the material being machined, or other moving tool components. Some mandrels are shaped bars of metal that are placed inside or next to the workpiece to be machined. These arbors are used to bend the exhaust pipes for automobiles, and in the production of molten glass, metal rings, threaded rods and furniture legs. Other mandrels are clamps that are used by lathes to hold materials during turning operations. There are several types of arbors for lathes. Expanding mandrels are slightly tapered and have an expandable wedge for holding the workpiece. Lathes also use mandrels that are set in the center and turned with lathe dogs. In addition to lathes, arbors are used to hold buffing wheels, circular saws, and sanding discs. Typically, these mandrels consist of a cylinder that is threaded on one end. There are many different types of mandrels for specialized applications. Examples include live chuck mandrels, live bull ring mandrels, and dead bull ring mandrels. Live chuck mandrels are designed for rolls with damaged center holes. These high-precision arbors provide maximum rigidity and long bearing life. Live bull ring mandrels are used to center large-diameter parts. They have heavy-duty bearing assemblies and come in a variety of tapers. Live bull rung mandrels also provide long bearing life. They have rings that range from 5 to 60 inches in diameter. Dead bull ring mandrels are also available. Types of these arbors include called 4-Morse taper, 5-Morse taper, and 6-More taper dead-center mandrels. Product specifications for mandrels include diameter hole size, tool type and series, drill-collar size, length, body diameter, blade length, fishing neck, and weight. Materials of construction include aluminum, steel, and composite materials. Metal mandrels are often tempered, heat-treated, and/or oil-quenched. Available shapes include oval, rectangle, square, diamond, rhomboid, hexagon, and octagon. Arbor dimensions such as diameter, body diameter and length are measured in either inches (in) and fractions of inches, or centimeters (cm) and millimeters (mm). Similarly, the weight of mandrels is expressed in either pounds (lbs) and fractions of pounds, or grams (g) and kilograms (kg). In terms of maintenance, mandrels should be checked periodically for the build-up of resin or excess materials.