Late Machine Operations

• Face Turning

  An operation of machining the ends of a workpiece square with its axis. To produce a flat, square surface and work is often held in a chuck, faced to length and center drilled in one setup.
• Parallel Turning

  An operation of machining the workpiece to produce a true diameter.
• Shoulder Turning is an operation of machining to produce more than one diameter on a piece of work, the change in diameters or known as step is called a shoulder. There are three common types of shoulders and they are square, filleted, and angular or tapered.
• Knurling

  Is a machining operation of impressing a diamond-shaped or straight line pattern into the surface of the workpiece to improve its appearance or to provide a better gripping surface.
• Grooving

  Commonly called recessing, undercutting, or necking, is often done at the end of a thread to permit full travel of the nut up to a shoulder, or at the edge of a shoulder to ensure a proper fit of mating parts.
• Form Turning

  It is often necessary to form irregular shaped or contours on a workpiece. Form turning may be done on a lathe by three methods.
• Taper Turning

  Defined as a uniform change in the diameter of a workpiece measured along its axis.
• (D-d)/I

  Formula for Taper calculations.
• Thread Cutting

  A machining operation that produces a helical ridge of uniform section on a workpiece.
• High Speed Steel Toolbits

  Probably the toolbit most commonly used in schools for lathe operations. High speed steels may contain combinations of tungsten, chromium, vanadium, molybdenum, and cobalt. They are capable of taking heavy cuts, withstanding shocks, and maintaining a sharp cutting edge under red heat.
• Cast Alloy Toolbits

  Usually contain 25 to 35 percent chromium, 4 to 25 percent tungsten, 1 to 3 percent carbon; and the remainder is cobalt. These toolbits have high hardness, high resistant to wear, and excellent red hardness qualities.. since they are cast, they are weaker and more brittle than the high speed toolbits. They may be operated about to two time the speed of a high speed toolbits.
• Cemented Carbide Toolbits

  Have low toughness but high hardness and excellent red hardness qualities.