DIN 933Hexagon headExternal hexagon

DIN 933 M20 × 35 Hexagon head

DIN 933 M20 × 35 is a hexagon head bolt with a 35 mm nominal length, on a M20 × 1.5 mm metric thread. A hexagon head fastener threaded all the way to the head. Glyph marking on the head identifies the property class, normally 8.8, 10.9 or A2-70.

Dimensioned drawing — DIN 933 M20 × 35k 12.5L 35⌀33.53⌀20
DIN 933 M20 × 35 — Hexagon headNominal dimensions in mm · Not to scale
Diameter20 mm
Length35 mm
Pitch1.5 mm
Socket size s30 mm
Head height k12.5 mm
HeadHexagon head
DriveExternal hexagon

Dimensions

Standard
DIN 933
Type
Hexagon head bolt
Size
M20 × 35
Length L
35 mm
Socket size s
30 mm
Head height k
12.5 mm
Drive
External hexagon
Head
Hexagon head

Nominal values in millimetres as published in DIN 933. Estimated weight 86.315 g per piece in steel (86.865 g in stainless), calculated from the nominal geometry — real parts vary with tolerance and head chamfers.

DesignationM20 × 1.5 fine
Pitch1.5 mm
Nominal Ø20 mm
Pitch Ø19.03 mm
Minor Ø ext18.16 mm
Tap drillØ 18.5 mm

Other lengthsDIN 933 M20

All M20 specifications

Interchangeability

DIN 933 is catalogued with ISO 4017 as its equivalent designation. Dimensions are compared field by field rather than assumed identical.

Choosing and fitting this size

DIN 933 M20 × 35 is a hexagon head in M20, 35 mm long under the head, on a 1.5 mm coarse pitch. Mating threads should be a matching class nut or a tapped hole of the same nominal size.

Common stock grades are 8.8, 10.9 and 12.9 in steel, plus A2-70 and A4-80 in stainless. Class 10.9 and 12.9 carry roughly 1.25 and 1.5 times the proof load of 8.8, but they also need a properly rated mating nut — a class 8 nut under a 12.9 bolt simply moves the failure into the thread. Zinc-plated 10.9 and above should be baked to avoid hydrogen embrittlement.

For a tapped hole, M20 × 1.5 mm takes a 18.5 mm tap drill, and the external thread's minor diameter is 18.16 mm — that is the section carrying the load, not the nominal M20 figure. Thread engagement of at least one times the nominal diameter is what lets the bolt fail before the thread strips.