Quick answer: A coupling element part number is a brand code, not a dimension, so cross-reference it in four steps: read the coupling brand and size code from the hubs, measure tooth-to-tooth OD for gear sleeves or OD/bore/height plus lobe count for spiders and rings, match the profile family, then confirm the compound and hardness. Our 12 series cover the common families - HRC and L jaw spiders, FCL pin-and-bush rings and sleeves, NM and N-EUPEX style elements, NOR-MEX elements, GR grid elements, H-block shear blocks, and J / H / HS / E gear coupling sleeves.
When a maintenance team sends us a reference such as a compression part number on a turbine oil pump coupling, the first thing our engineers do is ignore the number and look at the geometry. Part numbers differ between every coupling brand, but the elastomer inside is almost always one of a handful of standard profiles. This is the cross-reference routine we use every day.
Why the OEM number alone is not enough
A part number tells you which brand catalogue the part came from, not how big it is. The same profile appears across dozens of brands with different codes, and the same brand reuses codes for different sizes over the years. Dimensions travel; numbers do not.
Step 1 - read the coupling, not the part
Look at the coupling hubs and flanges first. A brand and size code cast into the metal - HRC 140, L090, NM 148, FCL #5, or a gear coupling size - already narrows the profile family down to one or two candidates.
Step 2 - identify the profile family
- Internal teeth, ring-shaped, clamped between two hubs: gear coupling sleeve (our J, H, HS and E profiles).
- Curved arms, sits between two hub jaws: jaw coupling spider (our HRC and L profiles).
- Straight-sided lobes on a round body: star element (NM, NOR-MEX style).
- Large ring plus small sleeves on each bolt: pin-and-bush coupling (FCL).
- Serpentine element that grips a grid: grid coupling element (GR).
- Rectangular block with a bolt hole: shear block (H-block, Holset style).
Step 3 - measure four dimensions
- Gear sleeves: tooth-to-tooth OD, tooth-to-tooth ID, overall height, tooth count (for example 12H is 242 mm OD, 24 teeth, 120 mm high).
- Spiders and rings: outside diameter, bore, height or jaw width, and the number of lobes.
- Star elements: outside diameter, bore, thickness.
- Shear blocks: block length, width, height and the bolt hole diameter.
Step 4 - confirm the compound
The same dimensions are moulded in several compounds, and the compound decides how long the part lasts. Tell us the duty (continuous, shock-loaded, oily, hot, outdoor) and we will confirm the right rubber, PU or Hytrel grade rather than simply copying the original hardness.
Series cross-reference table
- HRC jaw couplings (HRC 70 to 280) - our HRC spider series, eight sizes.
- L / LA / AL jaw couplings (L-050 to L-225) - our L spider series, nine sizes.
- FCL pin-and-bush couplings (FCL #1 to #8) - our FCL rings, sleeves and bolt sets.
- N-EUPEX and similar plug-in elements (NM 50 to 214) - our NM series, ten sizes.
- NOR-MEX elements (148-10 to 415-10) - our NOR-MEX series, ten sizes.
- Grid couplings (GR 14 to 125) - our GR grid element series.
- Gear couplings with J, H, HS or E profile sleeves (3J to 14J, 6H to 12H, 6HS to 12HS, 4E to 12E) - our gear sleeve series, plus matching cast iron hubs.
- H-block / shear block couplings (H80 to H610) - our H-block range with A/B dimension variants.
If the reference is an OEM catalogue number without a drawing, send a photo of the worn part next to a ruler or a coin, or post us one worn sample. A sample is the fastest route: our engineers measure it, confirm the profile and quote the replacement. Start a cross-reference request or see how to measure a worn coupling elastomer.