DIN 933Hexagon headExternal hexagon

DIN 933 M20 × 100 Hexagon head

DIN 933 M20 × 100 is a hexagon head bolt with a 100 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.

DIN 933 M20 × 100 — Hexagon headNominal dimensions in mm · Not to scale

Diameter20 mm

Length100 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 × 100
Thread: M20 × 1.5
Length L: 100 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 246.615 g per piece in steel (248.186 g in stainless), calculated from the nominal geometry — real parts vary with tolerance and head chamfers.

Thread data

Full M20 thread page

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

M20 × 30 M20 × 35 M20 × 40 M20 × 50 M20 × 60 M20 × 70 M20 × 80 M20 × 100 M20 × 120

Interchangeability

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

Equivalent standardISO 4017Hexagon Head Screw — Full Thread, Product Grade A/B ComparisonDIN 933 vs ISO 4017Field-by-field differences and a substitution verdict

Choosing and fitting this size

DIN 933 M20 × 100 is a hexagon head in M20, 100 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.