Involute Splines Component Generator
Concept Procedure Quick Reference

Tolerances (for ANSI standard)

Specifies the tolerance class and spline type.


Ribbon: Design tab Power Transmission panel Involute Splines. In the Involute Spline Connection Generator, click the button next to the Length edit field.


Confirms the selection and closes the dialog box.


Closes the dialog box.

Spline Type

Straight-toothed Spline

Toothed splines for small angle inaccuracy (maximum 1 degree).

Crowned Spline - flexible

External splines with crowned teeth for misalignment up to five degrees.

Tolerance class

Select the class of the tolerances.

This standard includes four classes of tolerances on space width and tooth thickness. This provides a range of tolerances for selection to meet a design need. The classes are variations of the former single tolerance which is now Class 5 and are based on the formulas shown in the footnote of Table 4. All tolerance classes have the same minimum effective space width and maximum effective tooth thickness limits so that a mix of classes between mating parts is possible.

For other tolerance classes:

Class 4 = 0.71 x Tabulated value

Class 5 = As tabulated in table

Class 6 = 1.40 x Tabulated value

Class 7 = 2.00 x Tabulated value

Types and Classes of Involute Spline Fits

National Standard for involute splines, the side fit, and the major diameter fit.

Dimensional data for flat root side fit, flat root major diameter fit, and fillet root side fit splines are tabulated in this standard for 30-degree pressure angle splines; but for only the fillet root side fit for 37.5- and 45-degree pressure angle splines.

Side Fit: In the side fit, the mating members contact only on the sides of the teeth; major and minor diameters are clearance dimensions. The tooth sides act as drivers and centralize the mating splines.

Major Diameter Fit: Mating parts for this fit contact at the major diameter for centralizing. The sides of the teeth act as drivers. The minor diameters are clearance dimensions. The major diameter fit provides a minimum effective clearance that allows for contact and location at the major diameter with a minimum amount of location or centralizing effect by the sides of the teeth. The major diameter fit has only one space width and tooth thickness tolerance which is the same as side fit Class 5.

A fillet root may be specified for an external spline, even though it is otherwise designed to the flat root side fit or major diameter fit standard. An internal spline with a fillet root can be used only for the side fit.

Design tab