Buyer summary
What to prepare before an RFQ
- Describe what the control input does and what movement appears at the connected mechanism.
- Use lost motion and backlash as working terms, then define the project measurement and acceptance criteria.
- Record mounting, route, interfaces, neutral position and change of direction with the sample or drawing.
- Do not infer a safe limit, allowable tolerance or root cause from a symptom alone.
Common mistakes
Details that often cause RFQ rework
Confusing the cable’s specified stroke with useful movement at the controlled mechanism.
Reporting an acceptable or unacceptable amount of play without identifying the test setup.
Ignoring brackets, mounts, mating hardware or the operating route when describing movement.
Changing a cable from a single symptom without checking the complete mechanism.
When a mechanical control moves but the connected mechanism does not respond as expected, the first useful step is to describe the movement at both ends. A cable’s specified stroke is not the same thing as the system’s useful output response. Terms such as lost motion, backlash, free play and dead band can also vary between projects, so the buyer should define the reference points and observation method rather than relying on a label alone.
This guide supports OEM specification and supplier discussions. It does not diagnose a particular machine, prescribe a repair, or set a universal allowable movement. Identify the intended Push Pull Control Cable or other cable family, then compare sourcing requirements through Custom Mechanical Control Cables before evaluating configurations.
Separate the cable range from the system response
Stroke or travel describes movement between stated positions. Lost motion describes a difference between movement at an input and the movement that becomes useful at an output. Backlash is often used for play that becomes apparent when direction reverses, but project and supplier terminology can differ.
These descriptions should not be collapsed into one dimension. A control may have a defined input travel while the assembled mechanism responds through linkages, brackets, mounts and a routed cable. The output movement observed in an installed system is therefore a system-level observation, not automatically a cable-only measurement.
The published Push Pull Control Cable Specifications guide already covers common cable dimensions such as housing length, overall length and stroke. This page focuses on defining the input-output relationship and the evidence needed when the observed response differs from the buyer’s requirement.
Establish reference points before comparing results
Choose stable points on the control input and work mechanism. Record the control position at the start and end of the movement, the corresponding output positions, and the direction in which the system was approached. If a lever, adjuster or linkage changes the geometry, show its position on the drawing or photograph.
For a repeatable discussion, identify:
- Equipment model or project identifier and the relevant cable assembly.
- The current drawing, sample or revision used for comparison.
- Control-end reference and work-end reference.
- Neutral or resting position and the intended direction of movement.
- Whether the observation includes a direction reversal.
- Cable route, housing supports, mounting brackets and mating hardware.
- The buyer-defined method and acceptance criteria, if they exist.
If a number is supplied, explain what was measured, where the tool was placed and which parts of the mechanism were included. An unlabeled figure does not show whether the value describes the inner cable, housing, lever, output mechanism or complete system.
Include mounting and route conditions
Control cable movement depends on its installed context. Show whether the outer housing is secured at the points intended by the drawing. Include brackets, clamps, adjusters, guides and the equipment-side interface. A loose support or changed mounting position can affect what the operator feels, but a symptom alone does not establish a root cause.
Also record route changes, tight clearances, movement positions and any known contact with surrounding equipment. Do not use one observation from a removed cable to represent how the assembly behaves when installed. If the cable is being replaced, pair the sample with the machine context and explain whether the original worked as intended before the reported issue.
The Drawing-Based Cable Assembly service is the appropriate route when a controlled drawing or measured sketch is available. If the request begins with a used part, the Sample-Based Cable Matching path can organize the sample and interface evidence.
Define acceptance instead of borrowing a threshold
There is no universal acceptance value in this guide. The buyer’s design basis should define whether a movement difference matters, where it is measured, under which installation and operating conditions, and who approves the result. When no criterion exists, state that the value is open for engineering review rather than treating a supplier’s generic figure as an application requirement.
Keep functional acceptance separate from visual fit. A cable can appear to fit while the equipment-side response still needs to be checked under a project-defined method. Conversely, an observed difference does not by itself prove that a cable assembly is the cause. The surrounding mechanism and installation are part of the evidence.
If the application is safety-related or production-critical, follow the equipment owner’s approved inspection and work procedures. This article is an RFQ preparation guide, not an instruction to test moving equipment or change its adjustment.
Report a movement concern clearly
Use a short record rather than an informal description such as “loose” or “too much play.” State what the operator does, what the mechanism does, which direction is affected, and which components were in place. Attach a drawing or annotated photo showing the two measurement references.
If the cable is still installed, include one full route image, close-ups of both ends, mounting points and any adjuster. If it has been removed, mark the sample condition and retain the equipment context separately. Note whether any parts were changed after the observation.
Common mistakes
A common mistake is treating the cable’s nominal stroke as proof of the system’s output travel. Another is reporting backlash without specifying the direction reversal or reference points. A third is attributing a system-level symptom to the cable before showing brackets, linkage and mounting conditions. Finally, an unapproved tolerance can accidentally become an assumed supplier requirement.
FAQ
Is lost motion the same as cable stroke?
No. Stroke describes a movement range between defined positions. Lost motion describes movement that does not appear as useful output response under a stated setup. Record both only when both are relevant.
Does backlash always come from the cable?
No conclusion should be made from the term alone. Record the complete mechanism, mounting, route, interfaces and observed movement so the project team can review the system.
What if the buyer has no acceptance limit?
Mark the limit and verification method as open. The buyer or responsible engineering authority should define what response is acceptable for the application.
Can an OEM send a video instead of measurements?
A short video can add context if it safely shows both input and output references. It should supplement, not replace, a labeled drawing, sample identity and any project-defined measurements.