Spline Shafts 101

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Spline Shafts 101
Spline shafts offer superior torque transmission compared to other mechanical components. This is achieved through larger contact surface area and precise engagement between mechanical parts. Cold-rolled spline shafts from Grob, Inc. can be customized to meet a wide range of requirements. Grob inc.’s proprietary cold-rolling process not only increases the strength of the spline shaft, it produces a much higher surface finish than traditional hobbing techniques.

A spline shaft is a cylindrical shaft with teeth or ridges that facilitate the transmission torque between mechanical components in an assembly. This section will cover some general information about spline shafts, including how they’re made, considerations when designing spline shafts, and the differences between spline shafts and spur gears.

How Are Spline Shafts Made
At Grob Inc., a proprietary cold rolling process is used to create strong, durable spline shafts. The cold rolling process forms the spline shaft at room temperature without the use of cutting tools. This chip less process use precision ground forming tools to displace the material into the desired spline shape. The cold rolling process increases numerous mechanical properties such as hardness, surface finish, and strength. Cutting processes such as hobbing waste material and may reduce the strength of the final part by cutting through the grain of the metal, so cold rolling is the preferred method for fabricating spline shafts.

Design Considerations
The goal of a spline shaft design should be to maximize torque. Primary design considerations may include the thickness and height of the teeth, the required pressure angles of the intended application, and the coupling configuration and allowable tolerances. There are also a variety of spline types to consider, including:

  • Involute
  • Parallel
  • Crowned
  • Serrated
  • Helical
  • Ball


Spur Gears Vs. Spline Shafts
Both spur gears and spline shafts transmit torque from a source such as a motor to other parts of a mechanical assembly. They both also do so with precisely shaped teeth or splines that lock into the adjacent mating parts with maximum surface contact to reduce slipping. However, the amount of surface contact at any given point in time differs. Spur gears, for example, are only in contact with a very small area on the tooth at any given time. Conversely, spline shafts stay in full contact with the tangential pieces, with their full circumference aiding the transmission of torque.

Spline Shaft Selection Guide
Spline shafts are available in a variety of types and materials based on the needs of the intended application.

Types of Spline Shafts
At Grob, Inc., our standard selection of spline shafts is available in an extensive range of spline numbers with outside diameters ranging from 0.263–4.12 inches. Whether your project needs an industry standard spline shaft or a spline shaft with a customized tooth profile, our engineering team can help. We have the equipment and expertise to engineer and tool custom shafts using cold-rolled processes. We offer the following types of custom spline shafts:

  • Involute Spline Shafts
  • Metric Spline Shafts
  • Standard Spline Shafts
  • Straight Spline Shafts
  • Ball Spline Shafts


Spline Shaft Materials
At Grob Inc. we have the capabilities to work with numerous different types of metals, such as:

  • Alloy steels
  • Aluminum alloys
  • Carbon steel
  • Stainless steel


Industrial Applications
We’re proud to provide high-quality spline shafts and gears for a wide variety of industrial sectors, such as:

  • Automotive
  • Agricultural
  • Locomotive
  • Industrial
  • Manufacturing
  • Extrusion Machinery


Standard and Custom Spline Shafts from Grob, Inc.
At Grob, Inc., we prioritize quality in all of our manufacturing processes. Since 1951, Grob, Inc., has specialized in cold forming gears and spline-based mechanical parts that offer superior strength and reduced process waste. Today, we have a 100,000-square-foot manufacturing facility in Wisconsin and over 60 skilled employees.

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Expert Cold Rolling at Grob, Inc.
Grob, Inc. has been providing cold-rolled parts to a wide range of industries for more than 70 years. We’ve developed our own methods for cold forming gearssplines, shaftsbushings, and a variety of other metal parts. Our proprietary process facilitates the tightest tolerances in the industry while providing ultimate strength and optimal surface finishes.
We also feature non-standard stock lengths not offered by most competitors. We can offer smaller diameters in lengths up to 6 feet, and larger diameters up to 12 feet. Our customization capabilities are unmatched, and up to 70% o our business comes from providing custom-designed products.
At Grob, our innovative processes, extensive experience, and in-depth knowledge help us deliver superior products in short time frames—and at lower costs. Please contact us for more information or a quote on any of our standard or customized cold-formed products.