GB T 23935 is the standard cited for extension spring. This page sets out what the standard controls for this part, reproduces the dimensional table supplied against it, and notes the related designations referenced on drawings.
GB T 23935 — Scope
The table below lists the dimensions catalogued for extension spring — iso / din (series 143) under GB T 23935. The scope of GB T 23935 itself is not summarised here — where a figure matters, confirm it against the published document.
Tolerance & Product Grades
Product grade is a concept from dimensional fastener standards and does not apply to GB T 23935. Tolerances for this part are the limits shown against each dimension in the table.
Dimensions Specified by GB T 23935
| Wire dia d (mm) | Outer diameter De (mm) | Free length Lo (mm) | Initial tension F0 (N) | Rate k (N/mm) | Material | Reference standard |
|---|---|---|---|---|---|---|
| 0.8 | 6 | 30 | 2 | 2.5 | Music wire | DIN 2097 / GB/T 23935 |
| 1.0 | 8 | 40 | 4 | 4.0 | Music wire | DIN 2097 / GB/T 23935 |
| 1.2 | 10 | 50 | 6 | 6.5 | Music wire | DIN 2097 / GB/T 23935 |
| 1.6 | 14 | 70 | 10 | 12.0 | Music wire | DIN 2097 / GB/T 23935 |
| 2.0 | 18 | 90 | 18 | 20.0 | Music wire | DIN 2097 / GB/T 23935 |
| 2.5 | 22 | 120 | 28 | 32.0 | Music wire | DIN 2097 / GB/T 23935 |
| 3.0 | 28 | 150 | 45 | 55.0 | Music wire | DIN 2097 / GB/T 23935 |
| 4.0 | 40 | 200 | 90 | 110.0 | Music wire | DIN 2097 / GB/T 23935 |
Companion Standards
A complete specification for extension spring — iso / din (series 143) normally cites several documents: one for the geometry, one for the material or mechanical properties, and one for the finish. GB T 23935 is one of them, not all of them.
When to Specify GB T 23935
Choose GB T 23935 for international engineering work and OEM supply where ISO standards are the contractual reference. It is the default modern specification for extension spring — iso / din (series 143).
Custom manufacturing · Made to drawing
Need a spring to this standard in a non-standard size?
Parts built to GB T 23935 are already in the catalog, so a special is usually a variation on existing tooling rather than a new design — which is what keeps the cost down.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
