Thread pitch and head size chart
Pitch is the distance between neighbouring threads. Unless a part says otherwise, small metric screws use the coarse pitch shown here.
| Size | Coarse | Fine | Cap head Ø | Countersunk Ø | Hex key |
|---|---|---|---|---|---|
| M1.2 | 0.25 mm | — | 2.3 mm | 2.3 mm | 1.0 mm |
| M1.4 | 0.3 mm | — | 2.6 mm | 2.6 mm | 1.3 mm |
| M1.6 | 0.35 mm | 0.2 mm | 3 mm | 3 mm | 1.5 mm |
| M2 | 0.4 mm | 0.25 mm | 3.8 mm | 3.8 mm | 1.5 mm |
| M2.5 | 0.45 mm | 0.35 mm | 4.5 mm | 4.7 mm | 2.0 mm |
| M3 | 0.5 mm | 0.35 mm | 5.5 mm | 6 mm | 2.5 mm |
| M4 | 0.7 mm | 0.5 mm | 7 mm | 8 mm | 3.0 mm |
| M5 | 0.8 mm | 0.5 mm | 8.5 mm | 10 mm | 4.0 mm |
| M6 | 1 mm | 0.75 mm | 10 mm | 12 mm | 5.0 mm |
Where each size shows up
M1.2
Eyeglass hinges, watch cases, hearing aids, handheld game consoles, the very smallest laptop brackets
M1.4
Standard eyeglass hinge screw, camera bodies, phone internals, micro drones
M1.6
Laptop hinges and boards, connectors, small standoffs, instrument panels
M2
Laptop bottom covers, SSD brackets, cameras, drones, small enclosures
M2.5
The classic laptop bottom-case screw, hard drive cages, Raspberry Pi mounting holes
M3
PC cases, 2.5in drives, 3D printers, extrusion hardware, DIN-rail devices, robotics
M4
Rack panels and cage nuts, monitors, VESA 75/100 plates, machine covers, e-bike parts
M5
VESA 100 monitor mounts, bike bottle cages and disc rotors, rack rails, appliance panels
M6
VESA 200 mounts, bike brake calipers, machine frames, heavy enclosures, furniture
Gear for this job
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Thread pitch gauge
Confirm the pitch on the bench
Metric screw assortment
One box covering the common pitches