Square head bolts
This Japanese Industrial Standard specifies the steel square head bolts for general use (hereafter, referred to as “bolts”).
Further, the strength class column II (4T) of mechanical properties specified in this Standard will be abolished on April 1, 1999.

Check out other specifications
TECHNICAL SUPPLY CONDITIONS FOR THREADED STEEL FASTENERS PART 2 TOLERANCES FOR FASTENERS — BOLTS, SCREWS, STUDS AND NUTS — PRODUCT GRADES A, B AND C
Standard Specification for General Requirements for Flat-Rolled Stainless and Heat-Resisting Steel Plate, Sheet, and Strip
SURFACE DISCONTINUITIES ON BOLTS, SCREWS, AND STUDS IN FATIGUE APPLICATIONS
Taper Key Torque Transmission – Parallel Keys – Dimensions and Application
High-strength structural bolting assemblies for preloading Part 6: Plain chamfered washers