M1.2 Nut Dimensions: Thread & Diameter

Q: What size wrench or spanner do I need for an M1.2 nut?

An M1.2 hex nut typically requires a 3 mm wrench or socket. This is because the standard width across flats (s) for an M1.2 nut is 3.00 mm. Due to the small scale, precision electronics-grade tools are recommended for installation.

Q: Is M1.2 a common metric size?

M1.2 is a specialized size found predominantly in horology (watchmaking), medical hearing aids, and high-density PCB assemblies where standard miniature fasteners like M2 are too large.

M1.2 nut dimensions or sizes are critical for micro-mechanical assemblies, optical equipment, and precision electronic components. This size is specifically engineered to mate with fasteners having a 1.20mm nominal diameter and is available in M1.2 x 0.25 for the coarse series and M1.2 x 0.2 for the fine series where 0.25 and 0.2 represents the thread pitch in millimeters.

This charts is based on (DIN 934 / ISO 4032) standard for a regular series hex nut. The thread dimensions comply with DIN 13-1 (coarse series), DIN 13-21 (fine series) and ISO 68-1 standards to ensure a precise fit and reliable engagement across ultra-fine metric fastening systems.

Disclaimer: Actual dimensions, including the width across flats (spanner or wrench size), nut height, and thread tolerance may vary depending on the specific manufacturing class and material — always verify with the official product datasheet before use or buying.

Nut internal thread diagram depicting major diameter, minor diameter, and pitch diameter

Nut body diagram depicting width across flats, width across corners, diameter, and thickness or height

M1.2 x 0.25 Hex Nut – DIN 13-1/ISO 68-1
Dimension	Size (mm)
Dimension	Min	Max
Major Diameter	1.2	1.307
Pitch Diameter	1.038	1.109
Minor Diameter	0.929	1.009
Thread Pitch	0.25

M1.2 x 0.2 Hex Nut – DIN 13-21/ISO 68-1
Dimension	Size (mm)
Dimension	Min	Max
Major Diameter	1.2	1.292
Pitch Diameter	1.07	1.133
Minor Diameter	0.983	1.058
Thread Pitch	0.2

M1.2 Hex Nut – DIN 934/ISO 4032 & ISO 8673
Diameter	1.2	1.4
Width Across Flats	2.9	3
Width Across Corners	3.28	Not specified
Height / Thickness	0.75	1

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Frequently Asked Questions

What size wrench or spanner do I need for an M1.2 nut?

An M1.2 hex nut typically requires a 3 mm wrench or socket. This is because the standard width across flats (s) for an M1.2 nut is 3.00 mm. Due to the small scale, precision electronics-grade tools are recommended for installation.

Is M1.2 a common metric size?

M1.2 is a specialized size found predominantly in horology (watchmaking), medical hearing aids, and high-density PCB assemblies where standard miniature fasteners like M2 are too large.