JIS B 1188 is the Japanese Industrial Standard for cross-recessed head screws with captive washers
According to typical JIS B 1188 data sheets, the dimensions for a standard M4 screw include: Thread Diameter: 4 mm Head Diameter (dk): 7 mm Head Height (k): 2.6 mm
| Parameter | JIS B 1188 (2003) | ISO 1207 | Old JIS (pre-1980) | | :--- | :--- | :--- | :--- | | Head diameter (M3) | 5.5 mm – 5.8 mm | 5.5 mm – 5.8 mm | 5.2 mm – 5.5 mm | | Head height (M3) | 1.65 mm – 1.85 mm | 1.65 mm – 1.85 mm | 1.5 mm – 1.7 mm | | Slot width (M3) | 0.8 mm – 1.0 mm | 0.8 mm – 1.0 mm | 0.6 mm – 0.8 mm | | Countersunk angle | 90° | 90° (ISO 2009/2010) | 82° or 90° (mixed) | jis b 1188 pdf
Single Washer Assemblies: Often featuring a spring lock washer or a plain flat washer.
Due to copyright laws, the official JIS standards are managed by the Japanese Standards Association (JSA). Free PDF copies on random document-sharing sites are often: JIS B 1188 is the Japanese Industrial Standard
Introduction
The Japanese Industrial Standard (JIS) B 1188 is a widely recognized specification for fasteners, particularly bolts, screws, and studs. This standard outlines the requirements for the design, materials, and testing of fasteners used in various industries, including construction, automotive, and manufacturing. In this blog post, we will delve into the details of JIS B 1188, its significance, and what it entails. This standard outlines the requirements for the design,
(commonly known as "Sems" screws). These fasteners are unique because the washers are mounted onto the screw blank before the threads are rolled, making them permanently attached. Direct PDF Resources Technical Specifications