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- Sep 22, 2010
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The two top images illustrate tables in horizontal and vertical orientations. The tables have standard Tee slots for mounting the work and most have a central hole that usually, but not always, has a Morse taper. Morse taper mounted devices can be easily mounted, but there is usually no way to properly close a MT collet. A standard feature of a Rotary Table is the calibration in degrees, minutes, and seconds on the table itself and on the worm gear shaft control wheel. The hand wheel usually has a Vernier scale for readings in seconds. This allows the setting of any arbitrary angle to a degree of accuracy that is limited only by the accuracy of the worm gear itself. However, it is not convenient for dividing a circle into a given number of divisions as when making a gear. As seen on the bottom right, many Rotary Tables have accessory division plates and an arm for using them. This photo shows the normal, degree, minute, second division hand wheel removed and the division plates in use. This does make dividing gears and hole circles a lot easier.
On the bottom left is a Rotary Table that can be tilted to any angle between 0 and 90 degrees. Thus, this feature, although somewhat rare on Rotary Tables, is not limited to only the Dividing Heads.
This photo shows some Dividing Heads. These are generally more compact than Rotary Tables and most have the tilting feature.
They usually have a spindle mounting area that is much like a lathe spindle which can accept collets, chucks, centers, and faceplates. They often have a matching tailstock to allow work the be mounted between centers. Although some degree markings are shown, they are not intended for accurate settings by angle as the Rotaty Tables are.
The first three photos show three different work holding devices mounted on these Dividing Heads: a collet chuck, a three jaw chuck and a dead center. Most Dividing Heads will also mount a faceplate or some means of driving a lathe dog.
Here is a chart that attempts to compare the features and capabilities of these three kinds of dividing devices:
