Buyer summary
What to prepare before an RFQ
- Separate nominal metal diameter, measured diameter and finished coated diameter in the RFQ.
- Check fitting compatibility, guides, sheaves, housing and clearance as one assembly question.
- Use application, movement, environment and existing sample evidence to support the diameter choice.
- State whether the request is a replacement, prototype or repeat-production assembly.
Common mistakes
Details that often cause RFQ rework
Calling a coated outside measurement the bare wire rope diameter.
Selecting the diameter from a fitting photo without checking the cable route or mating hardware.
Replacing a worn cable from its smallest measured section without recording wear or deformation.
Sending a diameter but omitting construction, coating, terminal and quantity context.
Wire Rope Diameter Selection for Complete Cable Assemblies
Choose wire rope diameter as part of the complete cable assembly, not as an isolated measurement. The useful RFQ separates nominal metal diameter, measured diameter, finished coated diameter, fitting interface, route clearance and application requirements. A measured value helps identify an existing cable, but it does not by itself approve the replacement.
This guide is for OEM buyers, maintenance teams and engineers preparing a wire rope assembly request. For the broader field list, see the Wire Rope Assembly Specification RFQ Guide. This page does not publish load ratings or safety factors.
Separate the diameter fields
| Field | What to record | Common confusion |
|---|---|---|
| Nominal metal diameter | The requested or drawing-defined rope size | It is not always the same as a worn sample measurement |
| Measured diameter | Tool, location and condition of the sample | Wear, flattening and strand position can change the reading |
| Finished coated diameter | Outside surface measured over the coating | It may be mistaken for bare rope diameter |
| Housing or guide clearance | Available passage and mounting space | A fitting or coating may control the actual clearance |
| Fitting interface | Bore, entry, stop, loop or terminal geometry | The terminal may require a different assembly method |
Write the measurement surface next to every number. “Diameter” without that context is often too ambiguous for a replacement quotation.
Start with the assembly route
The route tells the supplier what the cable must pass through, contact or connect to. Show guides, sheaves, pulleys, clamps, housing, brackets and the tightest clearance. If the cable moves, describe the movement direction and whether the route is static, occasional or repeated.
The Wire Rope Assemblies category and Custom Wire Rope Assembly page provide the product path. The final diameter still depends on the drawing, sample, cable construction, coating, fittings and application context.
Check the ends before approving a diameter
An end fitting is not just an accessory added after the cable is chosen. A sleeve, stop, eye, hook, threaded terminal or other end can control cable entry, finished dimensions, insertion, seating and the mating equipment. Label End A and End B, show the mating part and record the reference faces used for length.
If the fitting is coated, swaged or installed through a housing, the finished geometry should be reviewed with the diameter. Do not select a nominal size from a catalog image when the original equipment interface is available for measurement.
Construction and material remain separate
Diameter does not identify construction or material. Record 7x7, 7x19, stainless, galvanized or another requested field only when it is known from a drawing, sample record or buyer requirement. If the existing cable is worn or the construction is unclear, mark the field for review rather than guessing.
For material context, buyers can compare the Stainless Steel Wire Rope Assembly and the Wire Rope Assembly Specification RFQ Guide. These references organize the discussion; they do not make two assemblies interchangeable.
Replacement, prototype and production evidence
The measurement pack should identify the project stage:
- Replacement: used sample, route photos, equipment reference and wear notes.
- Prototype: drawing or measured sketch, intended interface, open design questions and initial quantity.
- Repeat production: approved reference, revision, quantity, packaging or labeling notes and any inspection request.
When the original drawing is missing, Sample-Based Cable Matching can organize the sample evidence. When a controlled drawing exists, use Drawing-Based Cable Assembly and mark each open field for confirmation before the Request a Quote step.
Diameter RFQ checklist
- Nominal diameter requested or identified from the drawing.
- Measured diameter, tool, location and measurement surface.
- Construction, material and coating if known.
- Finished outside diameter when coated or housed.
- Overall and effective length reference points.
- End A, End B, mating hardware and terminal dimensions.
- Route, guide, sheave, housing and available clearance.
- Application, environment, quantity and project stage.
For applications with a defined design load or safety requirement, attach the buyer’s design basis and request the appropriate engineering confirmation. Do not turn a generic measurement guide into a project rating.
Common mistakes
The most common error is sending the smallest worn measurement as the new order size. Another is reporting the coating surface as bare cable. A third is choosing a fitting and diameter separately even though they share the same interface. Keep the sample condition, intended specification and open questions visible in the RFQ.
FAQ
Should I order the measured diameter?
Use the measurement to identify the reference, then confirm the nominal diameter and completed assembly with the supplier. State whether the reading was over bare rope, coating or another finished surface.
Does coating affect diameter selection?
It can affect finished outside diameter and clearance. Provide both metal and finished dimensions when those fields are known.
Can the fitting determine the diameter?
It is useful evidence, but not the only basis. Review cable, termination, route, mating hardware and application together.
What belongs in a replacement RFQ?
Provide the sample or photos, measured diameter with surface identified, length references, both ends, route, equipment context, quantity and any drawing or revision information.