Short answer
Cut length is the length of the hose body to be prepared; overall assembly length is the completed dimension between defined end references. Without knowing the fitting contributions and the measurement method, no reliable conversion can be made from one to the other.
Technical explanation
ISO 4671 concerns methods for measuring hose dimensions and assembly lengths. For different end geometries, the reference points must be stated clearly. Finding the cut length by arbitrarily subtracting the total external length of the fittings can misrepresent the part of the hose that goes inside the fitting. A correct calculation is based on the manufacturer's effective length or assembly dimension data. The tolerance is also defined separately from the target length.
Topic-specific checkpoints
| Item | Description |
|---|---|
| Cut length | Preparation dimension of the hose body |
| Assembly length | Between specified end references |
| Fitting contribution | Product-specific effective length data |
| Tolerance | Acceptance depending on drawing and measurement method |
How to evaluate it in practice
On the order drawing, show the dimension line and the two reference surfaces. On the workshop cutting form, hose length and finished assembly length should be separate fields. When the fitting code changes, do not automatically keep the old cut length; verify the effective length contribution again. For elbow ends, explain which axis or surface the measurement is taken from. At acceptance, check that the measurement was made with the same method. Use the actual product drawing instead of an unclear 'fitting allowance' taken from an internet table.
Original editorial recommendation; not a clause of a standard.
Frequently asked questions
Is it enough to subtract the external lengths of the fittings from the overall length?
Not for every design. Insertion and effective length relationships must be taken from manufacturer data.
Source coverage
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S024
Hose and Flexible Tubing, MS-01-180 Swagelok · accessed 2026-10-19 PDF pages 4–5 / printed 253–254: Nomenclature; pages 8–9: selection, installation and use
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S076
ISO 4671:2022 ISO · accessed 2026-10-19 Abstract: dimensional measurement methods; public metadata only