Controlled tolerance record · non-normative arithmetic

Documented O-Ring Housing Tolerance Check

Calculate the limits of one signed dimensional tolerance and locate one measured O-ring housing dimension relative to that entered interval. Nominal dimensions and deviations must come from the exact controlled design source.

no ISO lookup tableno default squeezeno surface-finish presetno compliance verdict

This worksheet does not design an O-ring housing. It does not select an O-ring, application class, groove geometry, squeeze, stretch, fill, extrusion gap, back-up ring, surface texture or acceptance criterion. It only evaluates arithmetic from the controlled values you enter.

Controlled dimension and measurement

Use one dimension from one identified table row or approved drawing. Do not combine nominal values and deviations from different editions, classes or applications.

Dimension type

Shared linear unitChanging the unit clears all four numeric inputs and the result; no hidden conversion is performed.

Nominal dimension NPositive nominal linear dimension.

Measured dimension MPositive measured value on the same basis and at the recorded condition.

Signed lower deviation dLEnter the sign explicitly when negative; zero is allowed.

Signed upper deviation dUdU must be greater than dL; zero is allowed.

Exact dimension label and drawing feature

Governing standard/drawing, exact edition/revision and jurisdiction

Controlled table/figure/row or design-calculation reference

O-ring class, size code, d1/d2 and tolerance source

Application and housing configuration

Material and service-condition record

Surface texture, edge and lead-in requirements with source

Measurement method, instrument, uncertainty and condition

Check record ID and intended decision boundary

Required source and compatibility confirmation N, dL and dU were copied from the same applicable controlled table row, drawing characteristic or approved calculation; this page did not choose them. M uses the same feature definition, datum, unit, temperature/condition and measurement convention as the entered interval, with measurement uncertainty recorded separately. I will not use the interval relation as an O-ring design, material selection, manufacturing acceptance or ISO conformity decision without the controlling documents and competent review.

Arithmetic tolerance result

Entered interval [L,U]

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L=N+dL and U=N+dU in the selected unit.

Measured deviation e=M−N

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Signed arithmetic deviation from nominal.

Signed distances gL=M−L and gU=U−M

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Negative gL means below L; negative gU means above U.

Normalized interval position p=(M−L)/(U−L)

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Dimensionless coordinate; it may be below 0 or above 1.

Arithmetic relation to entered interval

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Descriptive relation only; not PASS/FAIL or conformity.

No acceptance verdict is produced. Measurement uncertainty, rounding rules, datum strategy, form error, surface texture, sampling and the controlling inspection plan can change the acceptance decision even when a displayed value lies numerically within the entered interval.

Formula and model boundary

For one positive nominal dimension N, positive measured dimension M, and signed deviations dL<dU on one common linear-unit basis:

L=N+dL · U=N+dU · e=M−N · gL=M−L · gU=U−M · p=(M−L)/(U−L)

L, U, e, gL and gU retain the selected unit. p is dimensionless. These are general arithmetic identities, not formulas supplied by ISO 3601.

Why the former ISO lookup was removed

The previous page supplied five O-ring cross-sections, one static and one dynamic groove pair per size, fixed tolerances and universal squeeze, fill, surface-texture and edge recommendations. It did not identify an ISO 3601-2 edition, table, O-ring class, size code, housing design approach, pressure direction, back-up-ring configuration or special-application agreement. It also treated piston and rod applications as the same dynamic row.

ISO 3601-2:2025 is now the current third edition and replaced ISO 3601-2:2016. Its public scope distinguishes class A and class B O-rings, multiple hardware-design approaches, general hydraulic/pneumatic applications with or without back-up rings, and aerospace housing dimensions. It states that special-application housing dimensions are expected to be agreed between manufacturer and user. The closed table values are therefore not reconstructed here.

Exact numerical checks

Invoer	[L,U]	e	gL; gU	p and relation
N=4.00 mm; dL=−0.05 mm; dU=+0.10 mm; M=4.06 mm	[3.95,4.10] mm	+0.06 mm	0.11; 0.04 mm	0.733333333333; inside interval
N=0.250 in; dL=−0.002 in; dU=+0.003 in; M=0.248 in	[0.248,0.253] in	−0.002 in	0; 0.005 in	0; on lower limit

Official source status and classification

Bron	Current public status inspected	Use on this page
ISO 3601-2:2025	Edition 3, published 2025-11-26; replaces withdrawn ISO 3601-2:2016	Official lifecycle and public scope only. No housing table value or tolerance is reproduced.
ISO 3601-1:2012	Edition 5, published and confirmed in 2022; Cor 1:2012 and Amd 1:2019 are published	Official lifecycle and public scope for d1, d2, tolerances and designation codes. No size table is reproduced.
Interval equations above	General dimensional arithmetic	Non-normative calculation from user-controlled values; not attributed to ISO.

ISO 3601-2:2025 official card · ISO 3601-1:2012 official card

Accessed: 15 July 2026. Licensed-source boundary: NEEDS_LICENSED_SOURCE for every housing dimension, deviation, squeeze/fill range, surface-texture value, edge/lead-in requirement and application-specific acceptance criterion. None was guessed from the withdrawn page, a search snippet or another calculator.

Design and metrology review required. Verify the current licensed standard/drawing, O-ring class and size, actual tolerances, compound/hardness, pressure and temperature, medium, motion, stretch/squeeze/fill, extrusion gap and back-up ring, finish/lead-in, manufacturing capability, inspection method and measurement uncertainty before a design or acceptance decision.