In precision manufacturing and automotive engineering, selecting the correct standard for fasteners determines product longevity and structural integrity. is a critical Japanese Industrial Standard (JIS) that governs cross-recessed screws equipped with captive washers. Often referred to as "sem-screws" or washer assemblies, these components are highly valued for streamlining assembly lines and ensuring consistent clamping force.
, published on March 21, 2017. This version remains the current and active standard as of the time of this writing.
He cross-referenced the PDF with his inventory drawers. Slide, clack, slide, clack. He found the Grade 10.9 steel bolts he’d ordered last week.
The Jis B 1188 standard is available in PDF format from various sources, including: jis b 1188 pdf
| 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) |
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He measured. 26.5 millimeters. He glanced back at the PDF. 26.5 min. , published on March 21, 2017
The standard covers various assembly configurations, primarily focusing on metric sizes for electronics and general-purpose applications. :
Commonly ranges from M2 to M10 coarse pitch threads.
| Property class | Tensile strength (MPa) | Hardness (HRC) | |----------------|------------------------|----------------| | 8.8 | 800 min | 22–32 | | 10.9 | 1040 min | 32–39 | | 12.9 | 1220 min | 39–44 | Slide, clack, slide, clack
Design engineers reference the maximum and minimum material limits from the PDF to create accurate 3D CAD models, preventing physical interference during physical prototyping. Differences Between JIS B 1188 and ISO/DIN Alternatives
. These fasteners are manufactured by mounting washers onto the screw blank before the threads are rolled, ensuring the washers remain permanently attached and free-spinning. Accuris Standards Store Standard Overview
Offers a wider bearing surface, frequently utilized in electrical applications.
Machinery housing and sensor mounting. How to Find and Utilize the JIS B 1188 PDF