10.3 Machine components
Micky R. Jennings
It is important that all lathe operators are familiar with the components of the machinery they are using. Getting to know the equipment, features, and functionality will help the machinist perform work in the safest and most efficient manner, as well as give them the industry-specific nomenclature necessary to effectively communicate with coworkers. One of the first things to consider when looking at a lathe is its size, or capacity. Lathes are sized by the diameter of work that can be turned, referred to as the swing, and the length of work that can be held between the spindle and tailstock. A common lathe size designation might be a 1340. This number designation means that a 13″ part can be turned over the bed, and it could be 40″ long in between the spindle and the tailstock.
Bed
The bed is the main structural component of the lathe. It runs horizontally, and most other components are attached to it. The bed contains the waysof the machine. The ways are precision flat or angular surfaces that give the machine its accuracy. The moving components that make up the linear movement of the lathe ride on the ways. The bed also supports the feed rod and lead screw.
Headstock
The headstock is attached to the left hand side of the bed. It contains the motor, spindle, and all the gearing required for machine speed changes. Some smaller machines may require the operator to change belt pulley positions or adjust a variable speed dial to alter speed. In the headstock, the spindle rotates on bearings.
Spindle
The spindle is located in the headstock and is driven by gears, shafts, belts, and pulleys attached to the motor. The nose of the spindle is where workholding devices are attached. Spindle speeds are generally altered by changing gears or occasionally by adjusting the power of a variable frequency drive. On latches equipped with power feed capabilities, the spindle will have gearing connected to it that provides power to the quick change gearbox, directly linking the two.
Motor
The motor is mounted to the backside of the lathe under the headstock. The motor has a pulley attached to it that is used to drive one or more belts to provide power to the lathe. Lathe motors come in different sizes, depending on the size and rigidity of the lathe. Industrial sized lathes often have 3 phase motors as opposed to the single phase motors found on smaller hobby machines.
Gears
The gears of the lathe are found inside the headstock, inside the quick change gearbox, inside the apron, and as a way to connect the headstock to the quick change gearbox. Some smaller lathes may require the operator to manually change one or more gears between the headstock and the quick change gearbox in order to alter the range of feeds the lathe is capable of.
Carriage
The carriage rides directly on the ways of the bed and is used to make axial movements of the lathe. The carriage supports both the cross slide and the compound rest. The carriage