What is the difference between Product Grade A and Grade B?

Product Grade A has tighter manufacturing tolerances and is used for bolts up to M24 and lengths up to 150 mm. Grade B has slightly looser tolerances and is used for bolts over M24 or lengths exceeding 150 mm.

Does this standard specify the tensile strength or yield strength of the bolts?

No, it is strictly a dimensional standard. Mechanical properties and testing requirements must be referenced from the IS 1367 series.

Are these bolts fully threaded?

No, IS 1364 (Part 1) specifically applies to partially threaded hexagon head bolts. Fully threaded screws are covered in Part 2.

IS 1364 Part 1

: 2017

Hexagon Head Bolts, Screws and Nuts of Product Grade A and B - Part 1: Hexagon Head Bolts (Size Range 1.6 mm to 64 mm)

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This standard specifies the dimensions, tolerances, and designation for partially threaded hexagon head bolts in the size range of M1.6 to M64. It categorizes bolts into Product Grade A for standard sizes and lengths, and Product Grade B for larger or longer bolts, aligning with ISO 4014.

Specifies dimensions and performance for hexagon head bolts of product grade A and B.

Quick Reference Values

size rangeM1.6 to M64

grade a size limitUp to M24 and length up to 10d or 150 mm

grade b size limitOver M24 or length over 10d or 150 mm

thread tolerance class6g

preferred lengths2 mm to 500 mm

Practical Notes

This part covers partially threaded bolts; for fully threaded hexagon head screws, refer to IS 1364 (Part 2).

Mechanical properties (such as property classes 4.6, 8.8, 10.9) are not detailed in this code; they are governed by the IS 1367 series.

Pay close attention to the unthreaded grip length (ls) and thread length (b) when detailing steel connections to ensure the shear plane does not fall within the threaded portion if prohibited by design.