The screws covered by JIS B 1188 are often referred to as —a term derived from "screw and washer assembly." The standard defines a manufacturing process where the washer is mounted onto the screw blank before the threads are rolled, making the washer permanently captive.

Standard hex bolts had a sharp corner that would bite into the new flange he’d machined. He needed a flange bolt, specifically the type defined in JIS B 1188, which provided a larger bearing surface to distribute the clamping force. This was crucial for the soft cast iron he was working with.

While the global manufacturing community continues to harmonize standards under the International Organization for Standardization (ISO), differences still exist between regional specifications:

The 1995 version is often available from third-party resellers like Fasten.one or JSAJIS.org at a lower cost (e.g., ~$25), but keep in mind that the 2017 standard is the most current for product design and compliance.

The standard provides comprehensive dimensional specifications for various thread sizes. Below is a representative example of dimensional data for JIS B 1188 screws:

Trivalent zinc plating (clear/yellow), nickel plating, or black oxide. The "JIS" Cross Recess Difference

A concise guide to head diameters, heights, and driver sizes for various thread pitches is hosted by Metric & Multistandard Components.

Sites like pdfcoffee.com , scribd.com , or internet archive may have old drafts or withdrawn versions. :

: Primarily focuses on Pan Head designs with a Phillips (cross-recess) drive. The head diameter and height are typically 5% to 20% smaller than standard pan head screws.

According to typical JIS B 1188 data sheets , the dimensions for a standard M4 screw include: : 4 mm Head Diameter (dk) : 7 mm Head Height (k) : 2.6 mm

Often case-hardened and coated with trivalent zinc, nickel, or black oxide for general-purpose applications.

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Simplifies supply chains by reducing two or three stock-keeping units (SKUs) down to a single component.