Specification summary of DIN 933 as applied to sealing screws with bonded washer: the dimensions the standard controls, the full specified size range, and the equivalent DIN/ISO/ASME designations.
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 Largely superseded by ISO 4017, which is the current reference for new designs.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 sealing screws with bonded washer 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) | Head height k (mm) | Seal outer diameter (mm) | Seal thickness (mm) | Seal material | Common length range (mm) | Reference standard |
|---|---|---|---|---|---|---|---|---|
| M5 | 0.8 | 8 | 3.5 | 10 | 1.0 | NBR | 8~40 | DIN 933 + BS 4518 |
| M6 | 1.0 | 10 | 4.0 | 12 | 1.5 | NBR | 10~50 | DIN 933 + BS 4518 |
| M8 | 1.25 | 13 | 5.3 | 14 | 1.5 | NBR | 12~60 | DIN 933 + BS 4518 |
| M10 | 1.5 | 17 | 6.4 | 16 | 1.5 | NBR | 16~60 | DIN 933 + BS 4518 |
| M12 | 1.75 | 19 | 7.5 | 19 | 2.0 | NBR | 20~80 | DIN 933 + BS 4518 |
| M16 | 2.0 | 24 | 10.0 | 24 | 2.0 | NBR | 25~80 | DIN 933 + BS 4518 |
Equivalent Standards
Where direct equivalents exist (ISO ↔ DIN, ISO ↔ ASME), they are listed on the parent Sealing Screws with Bonded Washer 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 screw 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 warm forging.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
