[New JSA Standard Issued] Achieving Standardization of the 'Property Class 4.8 Torshear Type Hexagon Bolt' that Balances Safety and Efficiency on Construction Sites!
The Japanese Standards Association (JSA) has issued a new standard, 'JSA-S1028:2026,' for a torshear type hexagon bolt set developed by Tsukimori Industry. The bolt features a pin-tail that breaks upon completion of tightening, allowing for visual confirmation, thereby contributing to solving labor shortages and stabilizing quality in the construction industry.
📋 Article Processing Timeline
- 📰 Published: April 1, 2026 at 00:00
- 🔍 Collected: April 1, 2026 at 01:06 (1h 6m after Published)
- 🤖 AI Analyzed: April 22, 2026 at 05:05 (507h 59m after Collected)
The Japanese Standards Association (JSA) (Headquarters: Minato-ku, Tokyo; President: Hiroshi Asahi) issued the JSA standard "JSA-S1028:2026 Set of torshear type hexagon bolt of property class 4.8, hexagon nut and plain washer" regarding connection parts used for steel structures in civil engineering and construction on March 24, 2026.
This JSA standard was primarily developed by Tsukimori Industry Co., Ltd. The characteristic of this bolt set is its unique mechanism: by applying torque to the pin-tail provided at the tip of the bolt thread until the breaking groove twists and breaks, the bolt itself controls the breaking torque and maintains the bolt's tightening force within a predetermined range. Furthermore, the breaking of the pin-tail at the bolt tip allows for visual confirmation that the bolt tightening is complete. This makes it possible to ensure the safety of fastened structures at construction sites in Japan.
JSA-S1028:2026
"Set of torshear type hexagon bolt of property class 4.8, hexagon nut and plain washer"
Price including tax: 5,060 yen / A4 size / 28 pages
*Please note that prices for standards are subject to change.
[Background of Establishment and Expected Effects]
Currently, the tightening management of the "hexagon medium bolt" widely used at construction sites relies in part on the skill and senses of the installer, making objective confirmation difficult.
To solve this issue, we devised a plan to introduce the tightening mechanism of the "torshear type high-strength bolt," which has a long track record in civil engineering and construction sites, into a highly versatile property class 4.8 bolt. The primary goal is "transparency of construction," allowing anyone to confirm the completion of tightening at a glance due to the breaking of the pin-tail at the tip of the bolt.
The spread of this standard is expected to reduce the burden of construction management on site and homogenize the quality of structures. Particularly in the future construction industry, where a shortage of skilled workers is a concern, a system where "a consistent quality can be obtained no matter who performs the construction," without relying on special skills, will greatly contribute to economic and social infrastructure maintenance.
[Main Provisions]
- Terms and definitions
- Types and configurations of sets and configuration of lots
- Mechanical properties
- Shape and dimensions
- Threads and breaking grooves
- Testing and measuring methods
- Inspection
This JSA standard was primarily developed by Tsukimori Industry Co., Ltd. The characteristic of this bolt set is its unique mechanism: by applying torque to the pin-tail provided at the tip of the bolt thread until the breaking groove twists and breaks, the bolt itself controls the breaking torque and maintains the bolt's tightening force within a predetermined range. Furthermore, the breaking of the pin-tail at the bolt tip allows for visual confirmation that the bolt tightening is complete. This makes it possible to ensure the safety of fastened structures at construction sites in Japan.
JSA-S1028:2026
"Set of torshear type hexagon bolt of property class 4.8, hexagon nut and plain washer"
Price including tax: 5,060 yen / A4 size / 28 pages
*Please note that prices for standards are subject to change.
[Background of Establishment and Expected Effects]
Currently, the tightening management of the "hexagon medium bolt" widely used at construction sites relies in part on the skill and senses of the installer, making objective confirmation difficult.
To solve this issue, we devised a plan to introduce the tightening mechanism of the "torshear type high-strength bolt," which has a long track record in civil engineering and construction sites, into a highly versatile property class 4.8 bolt. The primary goal is "transparency of construction," allowing anyone to confirm the completion of tightening at a glance due to the breaking of the pin-tail at the tip of the bolt.
The spread of this standard is expected to reduce the burden of construction management on site and homogenize the quality of structures. Particularly in the future construction industry, where a shortage of skilled workers is a concern, a system where "a consistent quality can be obtained no matter who performs the construction," without relying on special skills, will greatly contribute to economic and social infrastructure maintenance.
[Main Provisions]
- Terms and definitions
- Types and configurations of sets and configuration of lots
- Mechanical properties
- Shape and dimensions
- Threads and breaking grooves
- Testing and measuring methods
- Inspection