DIN 933 covers the dimensional requirements for left-hand thread hex bolts. Reproduced below: the complete size table, and the companion and equivalent standards referenced when ordering to this document.
DIN 933 — Scope
DIN 933 is "Hexagon head screws, fully threaded". Largely superseded by ISO 4017, which is the current reference for new designs.
Material, property class, surface finish and packaging are governed by separate documents — ISO 898-1 and ISO 898-2 for mechanical property classes, ISO 4042 for electroplated finishes.
Tolerance & Product Grades
DIN 933 does not divide left-hand thread hex bolts 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 DIN 933
| Thread size | Pitch (mm) | Across flats s (mm) | Across corners e (mm) | Head height k (mm) | Thread direction | Common length range (mm) | Reference standard |
|---|---|---|---|---|---|---|---|
| M6 | 1.0 | 10 | 11.05 | 4.0 | Left-hand | 10~60 | DIN 933 LH |
| M8 | 1.25 | 13 | 14.38 | 5.3 | Left-hand | 12~80 | DIN 933 LH |
| M10 | 1.5 | 17 | 18.90 | 6.4 | Left-hand | 16~100 | DIN 933 LH |
| M12 | 1.75 | 19 | 21.10 | 7.5 | Left-hand | 20~120 | DIN 933 LH |
| M16 | 2.0 | 24 | 26.75 | 10.0 | Left-hand | 25~150 | DIN 933 LH |
| M20 | 2.5 | 30 | 33.53 | 12.5 | Left-hand | 30~150 | DIN 933 LH |
| M24 | 3.0 | 36 | 39.98 | 15.0 | Left-hand | 40~150 | DIN 933 LH |
Equivalent Standards
Where direct equivalents exist (ISO ↔ DIN, ISO ↔ ASME), they are listed on the parent Left-Hand Thread Hex Bolts page.
Always confirm against the dimensions on this page, since some "equivalent" standards differ in tolerances and head geometry.
When to Specify DIN 933
DIN 933 is still widely used in European mechanical engineering and as a cross-reference on legacy drawings; its ISO equivalent is preferred for new designs.
Custom manufacturing · Made to drawing
Need a bolt to this standard in a non-standard size?
Parts built to DIN 933 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 hot forging.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
