Cylindricity tolerance symbol

A circle between two slanting lines in a tolerance frame.

Also known as: Cylinder form tolerance

Engineering & technicalStandard profile

Meanings

Cylindricity controls roundness, straightness and taper at once along a whole cylindrical surface. It is the most demanding form tolerance and correspondingly the most expensive to hold, which is why it is specified sparingly.

Officially standardisedVerified fact
Limits the deviation of a whole cylindrical surface from a true cylinder, controlling roundness, straightness and taper together.
Contexts: Technical drawing
Common modern usageVerified fact
Is the most restrictive form tolerance and the most costly to achieve, so a drawing specifying it everywhere is usually over-specified.
Contexts: Technical drawing

Visual description

A circle with a slanting straight line touching it on each side, drawn in a rectangular frame.

Symmetry: none
Orientation: upright

Confidence

IdentityHigh confidence: High confidence because the identity is documented in encyclopedic references, but multiple independent sources agree.
Historical originModerate confidence: Moderate confidence because the historical origin is documented in encyclopedic references, but multiple independent sources agree, but early or supporting evidence is limited, but the regional or cultural match to this specific claim is not precise.
Current useHigh confidence: High confidence because the current use is documented in encyclopedic references, but multiple independent sources agree.
Visual matchHigh confidence: High confidence because the visual match is documented in encyclopedic references, but multiple independent sources agree.

Sources

ISO 1101, Geometrical product specifications — Geometrical tolerancing
International Organization for Standardization · retrieved 2026-08-01
Paywalled and NOT READ. Registered so records can state which standard governs a symbol — a checkable fact a reader can act on — and for nothing else. It governs the geometric tolerancing symbols and their frames. No meaning in any record is typed `official` on the strength of this entry. See docs/paywalled-standards.md.
Geometric dimensioning and tolerancing
Wikipedia · retrieved 2026-08-01
Tertiary reference. Used for what a symbol instructs and which standard governs it. Where a standard is named it is reported by this source rather than read, so no meaning is typed `official` on that basis.
ASME Y14.5, Dimensioning and Tolerancing
American Society of Mechanical Engineers · retrieved 2026-08-01
Paywalled and NOT READ. Registered so records can state which standard governs a symbol — a checkable fact a reader can act on — and for nothing else. It is the American counterpart to ISO 1101 and differs from it in detail. No meaning in any record is typed `official` on the strength of this entry. See docs/paywalled-standards.md.

Last reviewed 2026-08-23

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Engineering drawing notation

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Meanings

Officially standardisedVerified fact

Limits the deviation of a whole cylindrical surface from a true cylinder, controlling roundness, straightness and taper together.

Contexts: Technical drawing

Common modern usageVerified fact

Is the most restrictive form tolerance and the most costly to achieve, so a drawing specifying it everywhere is usually over-specified.

Contexts: Technical drawing

Confidence

IdentityHigh confidence: High confidence because the identity is documented in encyclopedic references, but multiple independent sources agree.
Historical originModerate confidence: Moderate confidence because the historical origin is documented in encyclopedic references, but multiple independent sources agree, but early or supporting evidence is limited, but the regional or cultural match to this specific claim is not precise.
Current useHigh confidence: High confidence because the current use is documented in encyclopedic references, but multiple independent sources agree.
Visual matchHigh confidence: High confidence because the visual match is documented in encyclopedic references, but multiple independent sources agree.

Sources

ISO 1101, Geometrical product specifications — Geometrical tolerancing
International Organization for Standardization · retrieved 2026-08-01
Paywalled and NOT READ. Registered so records can state which standard governs a symbol — a checkable fact a reader can act on — and for nothing else. It governs the geometric tolerancing symbols and their frames. No meaning in any record is typed `official` on the strength of this entry. See docs/paywalled-standards.md.
Geometric dimensioning and tolerancing
Wikipedia · retrieved 2026-08-01
Tertiary reference. Used for what a symbol instructs and which standard governs it. Where a standard is named it is reported by this source rather than read, so no meaning is typed `official` on that basis.
ASME Y14.5, Dimensioning and Tolerancing
American Society of Mechanical Engineers · retrieved 2026-08-01
Paywalled and NOT READ. Registered so records can state which standard governs a symbol — a checkable fact a reader can act on — and for nothing else. It is the American counterpart to ISO 1101 and differs from it in detail. No meaning in any record is typed `official` on the strength of this entry. See docs/paywalled-standards.md.

Last reviewed 2026-08-23