Global Gear Couplings

Technical reference library

A working reference for gear coupling standards, sizing and failure analysis.

What each standard actually governs, the arithmetic behind a size call, and what a worn coupling is telling you about the machine around it. Written to stay useful to a reader who buys their coupling from a competitor.

Published by
Super Mech Industries
Ahmedabad, India · 29 export countries
Articles
33
Clusters
7
Revision
2026.2

Only two of these three documents govern a coupling

AGMA 9002, DIN 3761/5480 and IS 3238 get cited on the same drawing as though they were alternatives. They are not — and a specification written as if they were cannot be satisfied.

Flagship comparison · Standards

AGMA 9002 vs DIN 3761/5480 vs IS 3238: which standard governs your coupling?

One is a bore-and-fit practice. One governs a whole coupling. The third governs a seal and a spline, and answers a question nobody asked it. What each covers, and which to name on a purchase order.

Start from the part you are holding

Torque crosses the whole tooth mesh rather than any flexing element, which is why a gear coupling is still the densest way to move high torque through a small diameter. The teeth are crowned — barrelled rather than straight — so each hub can tilt and slide while carrying load, and that single detail sets every limit in this library.
Annotated section through a gear coupling, with each part linking to its articleA longitudinal section along the shaft axis. A shaft enters from each side, each carrying a hub with crowned external teeth. A sleeve split at the centre into two bolted halves surrounds both hubs and carries the internal teeth that mesh with them. Seals sit at each end of the sleeve. Six numbered annotations link to the article covering that part; every destination is repeated as an ordinary link in the list below this drawing.1Bore & keyway2Crowned hub teeth3Sleeve & internal teeth4Seal5Bolted flange joint6The mesh

Figure 1. Double-engagement gear coupling in section, schematic and not to scale. Every annotated part links to the article that covers it.

No two shafts stay in line

Foundations settle, casings grow as they reach operating temperature, and two machines on separate baseplates never return to quite the same relative position. A rigid connection pushes that error straight into the bearings. A gear coupling absorbs it instead — in three independent modes, each with its own rating.
The three misalignment modes a gear coupling accommodatesThree schematics side by side, each showing a driving shaft on the left and a driven shaft on the right joined by a coupling. In angular misalignment the two shaft centrelines meet at an angle. In parallel misalignment the centrelines stay parallel but are offset from one another. In axial travel the centrelines remain collinear while the shafts move apart along their common axis.αAngulareParallel offsetsAxial travel
Figure 2. The three modes, exaggerated for clarity. α is angular misalignment between shaft centrelines, e is parallel offset between two still-parallel centrelines, and s is axial travel as the train grows and contracts. A coupling can sit well inside its torque rating and still fail because one of the three was exceeded — the arithmetic is in misalignment capacity.

Seven clusters

Every article belongs to one. Each hub names a recommended starting point.
  1. 01Standards & SpecificationsAGMA 9002, DIN 3761/5480, IS 3238 and ISO 14691 — what each document actually governs, and where a whole-coupling standard ends and a component standard begins.Start here · AGMA vs DIN vs IS: which standard governs your coupling?5 articles
  2. 02Selection & SizingService factors, torque calculation, misalignment capacity, bore and keyway — the arithmetic behind a size call.Start here · How to size a gear coupling5 articles
  3. 03Coupling TypesFull gear, half gear, flanged sleeve, spacer, brake-drum and vertical configurations — build differences and when each applies.Start here · Full gear coupling6 articles
  4. 04Failure AnalysisTooth wear, lubrication failure, misalignment damage, fretting corrosion and a diagnostic checklist.Start here · Diagnostic checklist5 articles
  5. 05MaintenanceLubrication guide, installation and alignment, inspection intervals and disassembly procedure.Start here · Installation and alignment4 articles
  6. 06Applications & IndustriesSteel rolling mills, cement plants, marine propulsion, pumps and compressors, cranes and hoists.Start here · Steel rolling mills5 articles
  7. 07ComparisonsGear couplings measured against grid, disc and elastomeric alternatives.Start here · Gear coupling vs grid coupling3 articles

33 articles published · Standards & Specifications leads the sequence

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How this is made

Editor

Priyansh Thummar

Coordinates the editorial programme for this library: commissioning articles, holding them to the source documents, and routing every technical claim through engineering review before it is published.

Technical review

Being established

No engineer has been named as technical reviewer yet, so no article here claims to have had one. Figures awaiting review say so in their references.

Sourcing

Articles are drafted with AI assistance and edited by a person. Standards are cited by designation and revision, never reproduced. Where a figure belongs to a manufacturer's range rather than to a standard, it is left out rather than invented.

Corrections

Evidence that something here is wrong is welcome, and corrections are made on the page and dated. Tell us, or read the editorial policy.