# Splines

Shaft/hub spline geometry, fit, engagement and inspection, with bounded standard and catalogue references.

Reviewed: 2026-11-01

Tags: parts-and-design, splines, shafts, power-transmission

## Define the connection

Specify the mating shaft and hub teeth, their standard and whether axial sliding is required.

**Original geometry check:** for an assumed straight involute spline with module `m = 2 mm` and `z = 22`, the pitch diameter is `d = mz = 44 mm`, angular tooth spacing is `360/22 ≈ 16.364°`, and circular pitch is `πm ≈ 6.283 mm`. In the cited Ondrives example, the 48 mm **reference diameter** is consequently not interchangeable with this calculated pitch diameter. Neither number should be substituted for a major/minor limit diameter or an inspection dimension without its governing definition.

Parallel straight-sided and involute splines are different geometry families. AGMA's publications catalogue lists **AGMA 945-1-B20** and **945-2-B20** as design/application information sheets covering both families, with the second addressing inch-based splines. Their scope includes geometry, fits, materials, manufacture, rating, inspection, lubrication and failure. A tooth count and outside diameter are therefore only part of specifying a connection. [AGMA publications catalogue, spline information sheets](https://members.agma.org/common/Uploaded%20files/__AGMA%20Publications%20Catalog.pdf)

## Standard family and fit come first

DIN 5480 concerns involute splines based on reference diameters. Its public Part 2 scope describes detachable, sliding or fixed shaft/hub connections, a 30° pressure angle, normally flank centering, exceptional diameter centering, and a fit system that accounts for effective form deviations. Do not assume every involute spline uses that pressure angle or those fits. [DIN 5480-2:2025-10 scope](https://www.dinmedia.de/en/standard/din-5480-2/394645667)

The public DIN record identifies **DIN 5480-1:2026-05** as a corrected edition following the October 2025 document. Preserve the actual required part and edition on the drawing; a catalogue based on an earlier standard is not evidence of conformance to every subsequent correction. Public metadata does not replace the full standard's dimension and inspection rules. [DIN 5480-1:2026-05](https://www.dinmedia.de/en/standard/din-5480-1/399672170)

| Requirement | Information to keep explicit |
| --- | --- |
| Geometry family | Governing standard/edition, internal versus external member, tooth count and profile |
| Size | Module or pitch system, pressure angle, reference and limiting diameters |
| Fit | Tooth/space tolerance classes, centering basis and required axial motion |
| Engagement | Useful contact length, entry chamfers, runouts and axial retention |
| Acceptance | Datums, inspection method, processing/finishing state and functional requirements |

Separate axial retention from torque transmission. A connection that slides together successfully has not thereby demonstrated the required load capacity or retention. Establish fit from the complete paired definitions rather than matching a nominal diameter alone.

## Read a catalogue designation carefully

Ondrives' splined-shaft/bushing catalogue, printed **Updated May 2022**, shows an external shaft designation `48x2.00x30x22x8f`. Its diagram identifies reference diameter, module, pressure angle, tooth count and tooth-thickness/tolerance information; the table lists this as a 48 mm reference-diameter, module 2, 22-tooth shaft. The shaft heading specifies DIN 5480 W 8f slide fit. These are that product family's definitions, not a complete generic substitution rule. [Ondrives precision splined shafts and bushings, shaft page](https://www.ondrives.com/images/uploaded/PSS%20PSBS%20PSB%20PSC%20Precision%20Splined%20Shaft%20and%20Bushings.pdf)

These calculations describe ideal spacing only. They do not generate a complete DIN profile, tooth-thickness limits, measuring-pin size or a mating part. Use the applicable standard and controlled drawings for those values.

## Manufacture and load review

Specify the material, condition, heat treatment and final contact surfaces. Agree how the manufacturing process will reach an internal or external profile, particularly near a shoulder or blind end. Show any required runout or relief as actual geometry, and distinguish overall tooth length from useful engagement after chamfers and incomplete end profiles.

For a proposed connection, review torque and its reversals, contact distribution, engagement, alignment, surrounding shaft/hub section, lubrication and wear conditions. Do not divide total load equally among all teeth and treat that assumption as an established rating. AGMA's scope explicitly treats rating, lubrication and failure alongside geometry; a supplier's dimension table is insufficient for those separate decisions. [AGMA spline design/application scope](https://members.agma.org/common/Uploaded%20files/__AGMA%20Publications%20Catalog.pdf)

Any change to tooth form, runout, hardening or surface finish needs review against both assembly and operating requirements. A relief that solves tool access can reduce the remaining section; a tighter fit can change assembly and sliding behavior.

## Inspection is more than outside diameter

Gleason offers go/no-go rings and plugs, variable spline gauges and setting masters. Its variable indicator gauges can report **effective and actual tooth thickness or space width**. Those are distinct measurement quantities; specify the intended method and limits instead of asking only for a caliper reading across the outside. [Gleason functional and electronic gauges](https://www.gleason.com/en/products/metrology/master-gears-and-gauges/functional-and-electronic-gauges/functional-and-electronic-gauges)

As a proposed receiving sequence, confirm identification and standard, check required dimensions/profile and datums, apply the agreed functional/variable inspection, inspect usable engagement and edge condition, and verify assembly requirements. Keep gauge calibration and the inspected processing stage with the record. A successful trial fit of one pair does not establish interchangeability across all permitted production limits.

## Source scope

Reviewed on the date above. DIN edition dates are taken from the publisher's records; Ondrives prints May 2022. The live Gleason page has no verified technical revision date. AGMA catalogue descriptions are used for scope, not as a replacement for the design methods themselves. Calculations and proposed review/receiving checks are editorial guidance under stated assumptions.

## Related reference

[Part features](index.md)