METRICcoarse60° flankISO 261

M2.5 × 0.45 Thread Dimensions

M2.5 x 0.45 is a coarse ISO Metric thread. Pitch is 0.45 mm, equivalent to 56.44 threads per inch. The recommended tap drill is nominal diameter minus pitch.

Major Ø2.5 mm
Pitch0.45 mm
Threads per inch56.44
Pitch Ø2.21 mm
Tap drill2.05 mm

Thread profile

millimetres unless stated
Thread profile — M2.5 x 0.45d 2.5d2 2.21d3 1.95mm60°P 0.45h3 0.276tap ⌀2.05
M2.5 × 0.45 — basic profile60° flank angle · Not to scale

Basic information

Designation
M2.5 x 0.45
Thread system
ISO Metric
Series
coarse
Standard
ISO 261
Basic profile
ISO 68-1 basic profile
Flank angle
60°

Dimensions

Major diameter
2.5 mm
Pitch
0.45 mm
Threads per inch
56.44
Pitch diameter
2.21 mm
Minor diameter (external)
1.95 mm
Minor diameter (internal)
2.01 mm
Thread depth
0.276 mm
Recommended tap drill
Ø 2.05 mm

How these values are derived

computed from the basic profile

These figures follow the ISO 68-1 basic profile of ISO 261. A 60° basic profile has a fundamental triangle height H = 0.866025 × P, with pitch diameter d₂ = d − 0.649519 × P, external minor diameter d₃ = d − 1.226869 × P and internal minor diameter D₁ = d − 1.082532 × P; the two minor diameters differ because the external root is rounded while the internal crest is truncated. The recommended tap drill is given as nominal diameter minus pitch, which approximates 75% thread engagement — adjust it for tough materials or deep holes.

Compatible parts68 specification pages

All M2.5 fasteners

Every fastener below is threaded M2.5 × 0.45, so a nut, bolt or washer picked from this list will mate with it.

DIN 912ISO 4762DIN 934ISO 4032DIN 84ISO 1207DIN 85ISO 1580DIN 963ISO 2009
SpecificationLength
DIN 912 M2.5 × 4 Hexagon Socket Head Cap Screw4 mm
DIN 912 M2.5 × 5 Hexagon Socket Head Cap Screw5 mm
DIN 912 M2.5 × 6 Hexagon Socket Head Cap Screw6 mm
DIN 912 M2.5 × 8 Hexagon Socket Head Cap Screw8 mm
DIN 912 M2.5 × 10 Hexagon Socket Head Cap Screw10 mm
DIN 912 M2.5 × 12 Hexagon Socket Head Cap Screw12 mm
DIN 912 M2.5 × 16 Hexagon Socket Head Cap Screw16 mm
DIN 912 M2.5 × 20 Hexagon Socket Head Cap Screw20 mm
DIN 912 M2.5 × 25 Hexagon Socket Head Cap Screw25 mm
ISO 4762 M2.5 × 4 Hexagon Socket Head Cap Screw4 mm
ISO 4762 M2.5 × 5 Hexagon Socket Head Cap Screw5 mm
ISO 4762 M2.5 × 6 Hexagon Socket Head Cap Screw6 mm
ISO 4762 M2.5 × 8 Hexagon Socket Head Cap Screw8 mm
ISO 4762 M2.5 × 10 Hexagon Socket Head Cap Screw10 mm
ISO 4762 M2.5 × 12 Hexagon Socket Head Cap Screw12 mm
ISO 4762 M2.5 × 16 Hexagon Socket Head Cap Screw16 mm
ISO 4762 M2.5 × 20 Hexagon Socket Head Cap Screw20 mm
ISO 4762 M2.5 × 25 Hexagon Socket Head Cap Screw25 mm
DIN 934 M2.5 Hexagon Full Nut—
ISO 4032 M2.5 Hexagon Regular Nut, Style 1—
DIN 84 M2.5 × 4 Slotted Cheese Head Screw4 mm
DIN 84 M2.5 × 5 Slotted Cheese Head Screw5 mm
DIN 84 M2.5 × 6 Slotted Cheese Head Screw6 mm
DIN 84 M2.5 × 8 Slotted Cheese Head Screw8 mm
DIN 84 M2.5 × 10 Slotted Cheese Head Screw10 mm
DIN 84 M2.5 × 12 Slotted Cheese Head Screw12 mm
DIN 84 M2.5 × 16 Slotted Cheese Head Screw16 mm
DIN 84 M2.5 × 20 Slotted Cheese Head Screw20 mm
ISO 1207 M2.5 × 4 Slotted Cheese Head Screw — Product Grade A4 mm
ISO 1207 M2.5 × 5 Slotted Cheese Head Screw — Product Grade A5 mm
ISO 1207 M2.5 × 6 Slotted Cheese Head Screw — Product Grade A6 mm
ISO 1207 M2.5 × 8 Slotted Cheese Head Screw — Product Grade A8 mm
ISO 1207 M2.5 × 10 Slotted Cheese Head Screw — Product Grade A10 mm
ISO 1207 M2.5 × 12 Slotted Cheese Head Screw — Product Grade A12 mm
ISO 1207 M2.5 × 16 Slotted Cheese Head Screw — Product Grade A16 mm
ISO 1207 M2.5 × 20 Slotted Cheese Head Screw — Product Grade A20 mm
DIN 85 M2.5 × 4 Slotted Pan Head Screw4 mm
DIN 85 M2.5 × 5 Slotted Pan Head Screw5 mm
DIN 85 M2.5 × 6 Slotted Pan Head Screw6 mm
DIN 85 M2.5 × 8 Slotted Pan Head Screw8 mm

Showing the first 40 of 68 specification pages. The dash in the Length column marks a nut or a washer: those parts have no length to quote, so the dash means not applicable rather than missing data.

Related

Other pitches at the same 2.5 mm diameter — a fine pitch on a coarse diameter, or the reverse, is the usual substitution question.

M2.5 × 0.35 fine

Neighbouring sizes in ISO Metric.

M1.8 × 0.2 fineM2 × 0.4M2 × 0.25 fineM2.2 × 0.45M2.5 × 0.35 fineM3 × 0.5M3 × 0.35 fineM3.5 × 0.6