Moving Object's Pivot Point
Maya 2012 Tutorial
How to Move Pivot Point in Maya
Often times you wish to rotate an object around a specific point or scale based on a different point. For example, you may want to animate the hands of a clock or have a forearm rotate at the elbow.
Select an object in your workspace and choose the Move Tool (w key).
Press and hold the d key while dragging the object's origin to a new location. You can also press the Home key (PC-Insert key), move the point, then press the Home (PC-Insert) key to cancel.
To test your new pivot point, select the Rotate Tool (e key) and rotate the object. It should now rotate around the new pivot point.
You can also rotate an object to a specified angle by entering values in the object's Channel Box. Once you enter your value press Enter + Esc. For more information on the Channel Box, see topic Channel Box.