GB/T 118 is the standard cited for internally threaded dowel pin. 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 118 — Scope
GB/T 118 is "Parallel pins with internal thread, hardened". GB/T 118 is the Chinese national adoption of the same document.
Tolerance & Product Grades
GB/T 118 does not divide internally threaded dowel pin — gb/t 118 / iso 8735 (series 099) into product grades. Tolerances are given as limits on the individual dimensions in the table.
Where a general-tolerance class is cited on the drawing instead, it applies to the dimensions not otherwise toleranced.
Dimensions Specified by GB/T 118
| Nominal diameter d (mm) | Length L (mm) | Internal thread | Material | Reference standard |
|---|---|---|---|---|
| 4 | 16 | M3 | Alloy steel | ISO 8735 / GB/T 118 |
| 5 | 20 | M4 | Alloy steel | ISO 8735 / GB/T 118 |
| 6 | 24 | M4 | Alloy steel | ISO 8735 / GB/T 118 |
| 8 | 30 | M5 | Alloy steel | ISO 8735 / GB/T 118 |
| 10 | 40 | M6 | Alloy steel | ISO 8735 / GB/T 118 |
| 12 | 50 | M8 | Alloy steel | ISO 8735 / GB/T 118 |
| 16 | 60 | M10 | Alloy steel | ISO 8735 / GB/T 118 |
| 20 | 80 | M12 | Alloy steel | ISO 8735 / GB/T 118 |
Companion Standards
GB/T 118 controls the geometry of internally threaded dowel pin — gb/t 118 / iso 8735 (series 099). Surface finish is governed by separate finish standards such as ISO 4042 for electroplating, and corrosion testing by ISO 9227 (neutral salt spray). Mechanical performance is set by the documents specific to this part family — ISO 898-1 and ISO 898-2 apply to bolts, screws, studs and nuts, and not here.
When to Specify GB/T 118
Choose GB/T 118 for international engineering work and OEM supply where ISO standards are the contractual reference. It is the default modern specification for internally threaded dowel pin — gb/t 118 / iso 8735 (series 099).
Custom manufacturing · Made to drawing
Need a pin to this standard in a non-standard size?
Parts built to GB T 118 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. Made by cold heading or turning.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.

