DIN 653 is the standard cited for knurled thumb screws, low type. 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.
DIN 653 — Scope
DIN 653 is "Knurled thumb screws, low type".
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 653 does not divide knurled thumb screws, low type 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 653
| Size | a_max (mm) | c (mm) | Head diameter dk (mm) | dk_max (mm) | dk_min (mm) | ds_nom_max (mm) | ds_min (mm) | e (mm) | Head height k (mm) | k_min (mm) | r (mm) | Knurling | Length range l (mm) | Reference standard |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| M1 | 0.75 | 5.5 | 5.74 | 5.26 | 1.5 | 1.25 | 0.5 | 0.5 | 2~6 | DIN 653 | ||||
| M1.2 | 0.75 | 6 | 6.24 | 5.76 | 1.5 | 1.25 | 0.5 | 0.5 | 2~8 | DIN 653 | ||||
| M1.4 | 0.9 | 7 | 7.29 | 6.71 | 2 | 1.75 | 0.5 | 0.5 | 3~10 | DIN 653 | ||||
| M1.6 | 1.05 | 7.5 | 7.79 | 7.21 | 2 | 1.75 | 0.5 | 0.5 | 3~12 | DIN 653 | ||||
| M2 | 1.2 | 9 | 9.29 | 8.71 | 2 | 1.86 | 1.5 | 2 | 1.75 | 0.5 | 0.5 | 4~16 | DIN 653 | |
| M2.5 | 1.35 | 0.3 | 11 | 11.35 | 10.65 | 2.5 | 2.36 | 2 | 2.5 | 2.25 | 0.5 | 0.6 | 5~18 | DIN 653 |
| M3 | 1.5 | 0.3 | 12 | 12.35 | 11.65 | 3 | 2.86 | 2 | 2.5 | 2.25 | 0.5 | 0.6 | 6~20 | DIN 653 |
| M4 | 2.1 | 0.4 | 16 | 16.35 | 15.65 | 4 | 3.82 | 3 | 3.5 | 3.2 | 0.5 | 0.6 | 8~25 | DIN 653 |
| M5 | 2.4 | 0.4 | 20 | 20.42 | 19.58 | 5 | 4.82 | 3 | 4 | 3.7 | 1 | 0.6 | 10~30 | DIN 653 |
| M6 | 3 | 0.5 | 24 | 24.42 | 23.58 | 6 | 5.82 | 4 | 5 | 4.7 | 1 | 0.6 | 12~30 | DIN 653 |
| M8 | 3.75 | 0.6 | 30 | 30.42 | 29.58 | 8 | 7.78 | 5 | 6 | 5.7 | 2 | 0.6 | 16~35 | DIN 653 |
| M10 | 4.5 | 0.8 | 36 | 36.5 | 35.5 | 10 | 9.78 | 6 | 8 | 7.64 | 2 | 0.6 | 20~40 | DIN 653 |
Companion Standards
DIN 653 controls only the geometry of knurled thumb screws, low type. The mechanical strength is set by ISO 898-1 (bolts, screws and studs) or ISO 898-2 (nuts); the surface finish is governed by separate finish standards such as ISO 4042 for electroplating. For corrosion testing, the relevant document is ISO 9227 (neutral salt spray).
When to Specify DIN 653
DIN 653 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 653 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.
