Considerations When Machining Splines

A spline is a tooth form that runs parallel to the axis of a shaft or to the bore of an internal component. This blog post is intended to address aspects of machining both external and internal splines.

Machining External Splines

When machining external splines, options for modern machining organizations include rolling, hobbing milling, and single point broaching. Rolling is ideal for high volumes, but is rather cost prohibitive for lower volume production.

Splines are typically rolled using dedicated spline rolling machines. These machines are equipped with spline racks. An example of a manufacturer of such dedicated equipment is Anderson-Cook, Inc. Although Triumph Tool is not involved in the sale and service of spline racks, we are very involved with spline rolling centers.

Spline rolling is very demanding on the live center. Our supplier Riten Industries offers a heavy-duty center designed specifically for spline rolling (see picture below). Riten is also very adept at offering various semi-standard points with, for example, smaller diameters and extended lengths. One of the benefits of using Riten is the very cost-effective reconditioning program.

Source: Riten Industries

When it comes to lower volume productions of external splines, hobbing, milling and single point broaching are commonly used. Consider:

• Triumph Tool is not involved in the sales and service of hobs, but we are involved in the other aforementioned areas.
• When milling a spline, one should consider Advent Tool & Manufacturing. Advent offers a standard range of spline milling inserts that fit their off-the-shelf standard indexable thread mills. Advent also offers special form inserts and solid carbide cutters.
• Triumph does offer driven tools from Benz Inc. for CNC lathes to drive arbor style hobs. This is common for large aerospace landing gear components, for example.
• Single point broaching is another popular method of machining both internal and external splines. Coupling the indexable cutting tool with a driven unit to save on machine travel is an ideal solution.

Source: Pilot Precision Products

Machining Internal Splines

Broaching is the most common method for machining internal splines in high production.  Single point broaching is gaining in popularity for lower volume jobs – see above reference to this for external splines.

Metalworking Fluids for Machining Splines

Machining of splines, whether internal or external, and regardless of methodology, requires the use of a high-quality metalworking fluid.

Straight oil has been the traditional go-to solution for most shops machining splines. But recent developments with vegetable oil-based, water soluble fluids can lead to significant cost reductions with part cleaning and other areas. Please consult with us on the benefits of Blaser Swisslube metalworking fluids.

Source: Blaser Swisslube

So, whether you are machining external or internal splines and regardless of your methodology, Triumph Tool can help improve your productivity and cut your overall costs of production. Contact us for more information.