A rotary table is precision engineering positioning device first used in the field of metal working. It allows the operator to cut or drill work at precise intervals along a fixed mechanical axis. Rotary tables are designed to accommodate different types of work such as curved and straight shafts, as well as rotating shafts.
The first rotary table used was invented by Achterberg in 1843. This type of table has the capacity to rotate in either clockwise or counter-clockwise directions. A similar type of table called a top-drive is used by plumbers and other operators for drilling into wooden dams and foundations. In addition, these tables have been used for casting iron and brass as well.
The rotary table has two working ends. At one end there is a table-top that rotates vertically over a vertical shaft, while at the opposite end there is a spindle that rotates horizontally over the workpiece. The rotary table can be moved vertically, horizontally, or diagonally in any direction depending on the operation it is operating on. A mill that operates from a vertical axis is usually placed above the workpiece so that the operator places the workpiece against the spindle at the appropriate position.
The typical rotary table consists of a table top, spindle, and vertical shaft with suitable holes in suitable positions for fastening the hand tools to the table. There are several features that must be present in a good rotary table. Firstly, the holes for the hand tools need to be drilled into suitable positions on the spindle at appropriate angles. Secondly, the table must allow adjustment of the elevation of the workpiece relative to the vertical axis of the chuck. The height of the chuck should be able to be adjusted easily and quickly without exerting pressure on the operator.
There are four types of rotary tables used in the fabrication of precision bearings and other mechanical components. These are fully indexed and manual controlled, semi-automatic, and automatic. Fully indexed rotary tables require the operator to manually move the spindle and move the pinsions in the appropriate way to determine the appropriate degree of bearing tension. Semi-automatic and automatic types eliminate the need for manual control. However, fully automatic operations need a reliable electrical motor to operate the chucks and other components.
A rotary table may be used for several applications including milling machines, drilling presses, power presses, lathes, grinders, and other machining operations. It is used as an alternative to an operational computer, laser control system, or CNC (Computer Numerated Control) machine for complicated curves and surfaces. The table enables operators to perform long range, high-precision machining operations that are often tedious and slow. It is an ideal solution for machining curved surfaces as well as solid shafts.