JIS B1189 specifies metric hex flange bolts commonly used in Japanese automotive, machinery, equipment and industrial applications. These bolts feature an integrated flange beneath the hex head, helping distribute clamping force over a wider bearing surface.

JIS B1189 flange bolts are often used where original Japanese hardware specifications must be matched. They may differ from DIN and ISO flange bolt standards in head size, flange diameter, thread pitch and wrench size, so proper identification is important before substitution.

JIS B1189 defines:

• Metric hex flange bolts

• Integrated flange dimensions

• Thread pitch by diameter

• Across-the-flats wrench size

• Head height and flange diameter

• Mechanical strength requirements

• Manufacturing tolerances

These bolts combine a hex head and built-in flange into a single fastener. The flange helps spread load across the joint and can reduce the need for a separate washer in many applications.

Related Standards include:

• DIN 931- Partial Thread Hex Cap Screws

• DIN 933-Fully Threaded Hex Cap Screws

• DIN 960- Partial Thread Fine Thread Hex Cap Screws

• JIS B1189- Hex Flange Screws