DIN 933 vs DIN 931 vs DIN 960 vs DIN 961 vs JIS B1180 — Metric Hex Bolt Standards Explained

Metric hex bolts are manufactured to several international standards, including DIN 933, DIN 931, DIN 960, DIN 961, and JIS B1180.

Although these fasteners often appear similar, they differ in:

• Thread configuration

• Thread pitch

• Intended application

• Head size (across the flats)

Understanding these differences helps ensure proper fit, correct tool selection, and reliable performance in machinery, automotive, and industrial maintenance applications.

What Is DIN 933

DIN 933 specifies fully threaded metric hex cap screws using standard coarse thread pitch. These bolts are widely used for general-purpose fastening where full thread engagement is required.

Key Characteristics

Fully threaded

Coarse thread

Standard hex head size

General-purpose fastening

Typical Applications

Machinery repair

Equipment assembly

Industrial maintenance

General mechanical fastening

What Is DIN 931

DIN 931 specifies partially threaded hex bolts. The unthreaded shank provides improved shear strength and alignment in load-bearing applications.

Key Characteristics

Partially threaded

Smooth shank section

Higher shear strength

Structural applications

Typical Applications

Heavy equipment

Structural assemblies

Machinery mounting

Load-bearing joints

What Is DIN 960

DIN 960 specifies partially threaded hex bolts with fine thread pitch. These bolts are designed for applications requiring higher clamping force and vibration resistance.

Key Characteristics

Fine thread

Partially threaded

Improved clamping force

Better vibration resistance

Typical Applications

Automotive engines

Precision machinery

Mechanical assemblies

High-vibration environments

What Is DIN 961

DIN 961 specifies fully threaded hex bolts with fine thread pitch. These fasteners provide increased thread engagement and precise adjustment capability.

Key Characteristics

Fine thread

Fully threaded

Higher adjustment precision

Improved load control

Typical Applications

Precision equipment

Mechanical assemblies

Fine adjustment systems

High-load connections

What Is JIS B1180

JIS B1180 is the Japanese Industrial Standard for metric hex bolts commonly used in automotive and machinery applications. Unlike many DIN standards, JIS bolts often have different thread pitch patterns and smaller head sizes.

One of the most recognizable features of JIS bolts is the reduced across-the-flats dimension compared to DIN or ISO hardware.

JIS Thread Pattern by Size

Size	Typical Thread Type	Example Pitch
M8	Coarse thread	1.25 mm
M10	Fine thread common	1.25 mm
M12	Fine thread common	1.25 mm
M14	Fine thread common	1.5 mm
M16	Fine thread common	1.5 mm

This pattern is frequently encountered in:

Japanese automotive engines

Industrial machinery

Equipment mounting systems

Replacement hardware applications

Head Size Difference — DIN vs JIS

One of the most important physical differences between these standards is the hex head size.

JIS bolts typically use a smaller wrench size than comparable DIN bolts of the same diameter.

Across-the-Flats (Hex Size) Comparison

Bolt Size	DIN / ISO Hex Size	JIS Hex Size
M8	13 mm	12 mm
M10	17 mm	14 mm
M12	19 mm	17 mm
M14	22 mm	19 mm
M16	24 mm	22 mm

Why the Smaller Head Size Matters

This difference affects real-world service and installation.

Practical Implications

Different socket or wrench requiredImproved clearance in tight spacesPotential confusion during replacementImportant for tool selectionImportant for torque accuracy

A common scenario in the shop:

You grab a 17 mm wrench for an M10 bolt—but it turns out to be JIS and needs a 14 mm wrench

That’s the telltale sign.

Quick Comparison — All Five Standards

Standard	Thread Type	Thread Style	Head Size	Typical Use
DIN 933	Fully threaded	Coarse	Standard	General fastening
DIN 931	Partially threaded	Coarse	Standard	Structural / load-bearing
DIN 960	Partially threaded	Fine	Standard	High-vibration / precision
DIN 961	Fully threaded	Fine	Standard	Precision / adjustment
JIS B1180	Full or partial	Coarse or fine by size	Smaller	Automotive / machinery

Coarse vs Fine Thread — Why It Matters

The difference between coarse and fine thread directly affects performance.

Coarse Thread

Faster installationMore tolerant of debrisBetter for general use

Fine Thread

Higher clamping forceBetter vibration resistanceMore precise adjustmentImproved load distribution

Fine thread fasteners are commonly used in:

Automotive systemsEngine assembliesPrecision machineryHigh-load connections

Are DIN and JIS Bolts Interchangeable

Sometimes—but always verify.

Before replacing hardware, confirm:

Diameter

Thread pitch

Length

Strength class

Head size

Wrench size

Most installation problems happen when:

Thread pitch is incorrectHead size is unexpectedFine thread is mistaken for coarse thread

How to Identify a JIS Bolt in the Field

Look for these signs:

Smaller hex head size

Fine thread on larger diameters

Used on Japanese equipment

Different wrench size than expected

Example:

M10 bolt with a 14 mm headVery likely JIS hardware.

How to Choose the Right Standard

Use DIN 933 for:

General-purpose fastening

Fully threaded applications

Use DIN 931 for:

Structural connections

Shear load applications

Use DIN 960 for:

Fine thread structural connectionsVibration resistance

Use DIN 961 for:

Fine thread with full engagement

Precision applications

Use JIS B1180 for:

Japanese equipment

OEM replacement

Automotive applications

Applications

These metric hex bolts are commonly used in:

Machinery repair

Equipment installation

Automotive service

Industrial maintenance

Manufacturing operations

Related Products

Metric Hex Cap Screws

Fine Thread Hex Bolts

JIS Hex BoltsHex Bolt

Assortments

Metric Hardware Kits