ISO Central recently announced the publication of the following new standards:  

ISO 4156-1:2021(E), Straight cylindrical involute splines — Metric module, side fit — Part 1: Generalities

ISO 4156-2:2021(E), Straight cylindrical involute splines — Metric module, side fit — Part 2: Dimensions

ISO 4156-3:2021(E), Straight cylindrical involute splines — Metric module, side fit — Part 3: Inspection

ISO 4156 (all parts) provides the data and indications necessary for the design, manufacture and inspection of straight (non-helical) side-fitting cylindrical involute splines.

Straight cylindrical involute splines manufactured in accordance with ISO 4156 (all parts) are used for clearance, sliding and interference connections of shafts and hubs. They contain all the necessary characteristics for the assembly, transmission of torque, and economic production.

The nominal pressure angles are 30°, 37.5° and 45°. For electronic data processing purposes, the form of expression 37.5° has been adopted instead of 37°30’. ISO 4156 (all parts) establishes a specification based on the following modules:

?for pressure angles of 30° and 37,5° the module increments are:

0.5; 0.75; 1; 1.25; 1.5; 1.75; 2; 2.5; 3; 4; 5; 6; 8; 10;

?for pressure angle of 45° the module increments are:

0.25; 0.5; 0.75; 1; 1.25; 1.5; 1.75; 2; 2.5.