Turn-Cut Enables Turning on Horizontal Machining Centers

Executive Summary

Turn-Cut is a programming option available on Okuma horizontal machining centers that allows the machine to create bores and diameters that include circular and/or angular features. This enables users to turn features on large, unbalanced parts on the same platform where standard CNC machining functions are performed. Turn-Cut eliminates the need to purchase special-purpose machines, tooling, fixtures or add-on components.

Turn-Cut operates by leveraging Okuma’s philosophy of manufacturing both control and machine, a mechatronics approach which provides a synergistic system that delivers greater reliability and optimized performance. It uses standard tooling, which, in most cases, saves on tooling costs. Turn-Cut works without additional motors, servos, and heavy attachments, and integrates with tooling already developed and readily available. Turn-Cut enhances the use of the machine without adding components or weight that may restrict its use during normal CNC machining operations.

Turn-Cut does not affect the performance or longevity of the machine, and in fact enhances performance with the addition of Abso-scales and chilled ballscrews. When heavy milling is required, the Okuma horizontal machining center equipped with Turn-Cut is still as capable as ever. Most importantly, Turn-Cut allows for processing work without the need to use a secondary machine for a turning application. Parts such as valves, pipe or manifold-type parts are ideal candidates for Turn-Cut.

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Turn-Cut is a programming option that enables a horizontal machining center to create surfaces that taper, arc or have any combination of varying diameter shapes along the Z-axis of a work piece (see Figure 1). The surfaces created by Turn-Cut can be either on the outside or inside diameter of the machined part. Turn-Cut can operate using standard tooling and minimal fixturing.

Turncut img1
Turncut img2 ff

Turn-Cut is used in applications that would traditionally use a CNC lathe to turn a feature (see Figure 2). In some cases, the part configuration (size, shape, weight) prohibits it from being set up on a lathe. With Turn-Cut, the part is stationary as the Turn-Cut programming creates the tool path. Enables Lathe Operations on a Horizontal Machining Center Lathe operation Turn-Cut operation.

Turn-Cut synchronizes the X & Y circular motion with the spindle angle to ensure the tool edge maintains its programmed path at all times. Turn-Cut is turned on by a G-code in the program and follows standard programming convention to describe the desired path.


  • Turn-Cut provides process optimization capabilities without a large investment in specialized tooling, attachments, fixturing or even a specialized machine tool. Turn-Cut can be installed on Okuma horizontal machining centers while maintaining the original performance of the machine. In nearly all cases, the additional options of the Turn-Cut package will make the machine perform more consistently, even in applications not requiring Turn-Cut.

  • Turn-Cut simplifies fixturing and reduces set up time as well. Standard fixturing can be used with Turn-Cut instead of complex fixtures typically required to orient the part.

  • Setup time is reduced since the part does not have to be moved to another machine to perform the operation handled by Turn-Cut.

  • Expensive index chucks are no longer needed for manufacturing of small valves or Ts. Turn-Cut on a horizontal machining center can perform the same operation with less fixturing investment.

  • Complex heads or specialized tooling used to control tool path are not required with Turn-Cut. The use of these types of attachments typically adds complexity to the setup and also adds extra weight past the spindle taper.


The Turn-Cut function performs cutting on a horizontal machining center by synchronizing the circular motion of the feed axis with the spindle's turning angle (tool tip position control). (See Figure 3).

  1. The tool turns by synchronizing high-speed circular motion on the feed axes X and Y with the turning angle of the spindle. The position of the turning tool tip is synchronously controlled so it is kept perpendicular to the workpiece face.

  2. The cross section configuration is commanded with Z-X as in a turning program. The X-axis is commanded with the radius of X-Y continuous circular motion.

The above features enable turning of cylindrical workpieces and inside/outside diameter tapers on the horizontal machining center. The program can be commanded in the very same manner as turning on a CNC lathe according to a turning program (Z-X).

With the center of the axes (0, 0) as the origin of the workpiece coordinate system:

  • Continuous circular motion can be commanded in place of the spindle; and
  • The feed axis dimension (Z) and the radius (X) can be commanded.
turning on a horizontal machining center diagram


There are technologies on the market designed to accomplish these tasks, including U axis heads, externally driven U axis heads, index chucks and special purpose machines. Following are the advantages of using Turn-Cut as a more efficient alternative to these technologies.

  • Use of a single tool for multiple diameters

  • Process intensive machining in one setup

  • Fewer tools, less set up required

  • Provides desired machining finish in seal surfaces

  • Can handle unbalanced workpieces

  • Maintains the machine’s standard functions

  • Works with readily available tooling components

  • Does not add weight, length or heat to the spindle in order to operate

  • Does not require special fixturing

  • Does not require special programming

  • Can also be used for threading


Turn-Cut minimizes capital equipment costs, eliminates the need for additional floor space in the shop, provides a robust platform for CNC machining, simplifies fixturing and reduces set up time. This creates efficiencies that maximize profitability.


For more information about Turn-Cut and the products on which it is available, check with your local Okuma Distributor, or contact us.

To see Okuma's Turn-Cut function in action, watch the video:

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