ISO 4028HeadlessHexagon socket

ISO 4028 M12 × 40 Headless

ISO 4028 M12 × 40 is a socket set screw, dog point with a 40 mm nominal length, on a M12 × 1.5 mm metric thread. ISO dog point counterpart, for positive axial location into a pre-drilled hole.

ISO 4028 M12 × 40 — HeadlessNominal dimensions in mm · Not to scale

Diameter12 mm

Length40 mm

Pitch1.5 mm

Socket size s6 mm

HeadHeadless

DriveHexagon socket

Dimensions

Standard: ISO 4028
Type: Socket set screw, dog point
Size: M12 × 40
Thread: M12 × 1.5
Length L: 40 mm
Socket size s: 6 mm
Drive: Hexagon socket
Head: Headless

Nominal values in millimetres as published in ISO 4028. Estimated weight 35.513 g per piece in steel (35.739 g in stainless), calculated from the nominal geometry — real parts vary with tolerance and head chamfers.

Thread data

Full M12 thread page

DesignationM12 × 1.5 fine

Pitch1.5 mm

Nominal Ø12 mm

Pitch Ø11.03 mm

Minor Ø ext10.16 mm

Tap drillØ 10.5 mm

Other lengthsISO 4028 M12

All M12 specifications

M12 × 12 M12 × 16 M12 × 20 M12 × 25 M12 × 30 M12 × 40 M12 × 50 M12 × 60

Interchangeability

ISO 4028 is catalogued with DIN 915 as its equivalent designation. Dimensions are compared field by field rather than assumed identical.

Equivalent standardDIN 915Hexagon Socket Set Screw — Dog Point ComparisonISO 4028 vs DIN 915Field-by-field differences and a substitution verdict

Choosing and fitting this size

ISO 4028 M12 × 40 is a headless in M12, 40 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.

Set screws are rated by surface hardness rather than tensile class — the common stock grade is 45H, which is hard enough to bite into a hardened shaft. Stainless set screws are not through-hardened and will not bite the same way, so they are a poor substitute where the point has to grip.

For a tapped hole, M12 × 1.5 mm takes a 10.5 mm tap drill, and the external thread's minor diameter is 10.16 mm — that is the section carrying the load, not the nominal M12 figure. Thread engagement of at least one times the nominal diameter is what lets the bolt fail before the thread strips.