The production and machining of components with intersecting axes involves high processing expenditure. These components were either processed on special machines, transfer lines, or conventional lathes in several chucking operations. Therefore, GMT developed an autoindexing chuck to meet the persistent problems in machining components with intersecting axes in a CNC Lathe.

With this chuck, it is possible to perform multiple turning operations in one setup. This not only shortens cycle time and boosts productivity. Additionally, autoindexing chucks enhance operational efficiency. Finally, GMT indexing chucks of different sizes are useful for machining automobile parts like Universal joints, spiders and valve bodies etc.

GMT’s Power Operated Power Indexing chucks are available with index position:
4 x 90° ,
3 x 120° ,
2 x 180°.


+/- 2 minutes


There are two aspects to this chuck, indexing and clamping. The integral hydraulic cylinders actuate clamping, de-clamping, indexing and locking of index drum. The oil flows to the different cylinders through a pipe bundle running through the spindle bore. Typically, during the chuck application, the moving lower jaw clamps the component through an integral cylinder. The upper jaw is stationary. Two, four-way solenoid valves hydraulically control the indexing of the chucks.

Additionally, the electrical circuit includes an adjustable time delay relay to set the time lag between indexing and locking cycles. Further, the chuck indexes while the main spindle is running and reduces machine downtime.


  • Auto indexing chucks are useful for machining components of large batches due to their short chucking and indexing time.
  • Also, multiple machining processes are possible in one operation.
  • It is possible to index automatically on the work while the machine spindle is rotating.
  • High precision and accuracy can be obtained

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