Calculation Results
Tolerance Band and Spline Diagram
The chart compares external tooth-thickness and internal space-width limits at the pitch circle.
Formula Used and Calculation Steps
How to Use This Calculator
- Select a shaft, hub, pair, inspection, reverse, or compatibility mode.
- Enter the reference diameter, module, tooth count, profile shift, and engagement dimensions.
- Enter drawing tolerances instead of treating calculated estimates as official limits.
- Choose the inspection method and enter measured values when available.
- Add torque and allowable stresses for a preliminary load review.
- Press calculate, review warnings, then export the report.
Example Data
| Preset | Reference diameter | Module | Teeth | Profile shift | Typical use |
|---|---|---|---|---|---|
| Small precision | 20 mm | 0.8 mm | 25 | 0.00 | Compact instrument drive |
| Medium transmission | 50 mm | 2 mm | 25 | 0.00 | General power transmission |
| Large industrial | 160 mm | 5 mm | 32 | 0.10 | Heavy machinery coupling |
| Ground shaft | 80 mm | 2.5 mm | 32 | 0.05 | High accuracy external spline |
DIN 5480 Spline Geometry and Inspection Guide
A DIN 5480 spline uses involute flanks to transmit torque between a shaft and hub. The calculator begins with module, tooth count, pressure angle, and profile shift. It then derives pitch, base, tip, root, and form dimensions.
Reference diameter and module must agree with the selected tooth count. A mismatch may reflect a drawing convention, profile modification, or incorrect input. The warning list identifies differences before inspection values are trusted.
Fit analysis compares external tooth thickness with internal space width. User-entered tolerances define minimum and maximum material conditions. This method avoids pretending that proprietary standard tables are freely embedded.
Measurement over pins or balls provides a practical workshop check. Span measurement checks several teeth using a base tangent relationship. Both values remain sensitive to element size, tooth count, and profile shift.
Reverse mode estimates profile shift from an entered over-elements value. It uses the same simplified model as the forward calculation. Final correction must use approved metrology software and calibrated gauges.
Manufacturing method affects allowances, surface finish, and root accessibility. Broaching suits many internal splines, while hobbing and grinding suit external forms. Tool limits can create undercut, interference, or incomplete root clearance.
The torque section is only an early design screen. It estimates tangential force, average flank pressure, and torsional stress. Real capacity depends on material, hardness, duty cycle, alignment, and load distribution.
Temperature correction adjusts displayed lengths back toward a twenty-degree reference. The change is usually small but matters during precision inspection. Use matching material coefficients and controlled measuring conditions for reliable results.
Always compare exported results with the controlling engineering drawing. Confirm tolerance classes, gauge practice, and manufacturing allowances independently. Qualified review remains essential before production parts are released safely.
Frequently Asked Questions
Does this calculator include official DIN tolerance tables?
No. It uses user-entered tolerances and general involute relationships, so licensed standards and approved drawings remain controlling.
Why is the pressure angle set to 30 degrees?
DIN 5480 designs normally use a 30-degree pressure angle. Custom mode allows other values for comparison.
What does the reference diameter warning mean?
It means the entered reference diameter differs from module multiplied by tooth count beyond the selected tolerance.
Can this calculator verify a shaft and hub pair?
Yes. Pair and compatibility modes compare geometry, tooth thickness, space width, backlash, and entered tolerances.
Are over-pins and span values exact inspection values?
They are engineering estimates. Use approved inspection equations, calibrated equipment, and the controlling drawing for acceptance.
What is profile shift?
Profile shift changes tooth thickness and tip or root geometry without changing module or tooth count.
Can I use inches?
Yes. Inputs and outputs can be displayed in inches while calculations are internally normalized to millimetres.
What does the load safety factor represent?
It compares entered allowable pressure or shear with simplified calculated stress. It is not a fatigue rating.
Can I save and share calculations?
Yes. The page supports browser storage, shareable query URLs, copying, CSV, JSON, PDF, and print output.