What does Product Grade C mean?

It refers to fasteners manufactured with wider dimensional tolerances and lesser precision compared to Grades A and B, suitable for general-purpose structural connections.

What is the difference between Part 1 and Part 2 of IS 1363?

Part 1 specifies hexagon head bolts (which have an unthreaded shank portion), whereas Part 2 specifies hexagon head screws (which are threaded all the way to the head).

Where are the mechanical properties for these bolts defined?

The mechanical properties, such as tensile strength and yield stress, are governed by IS 1367 (Part 3).

IS 1363 Part 1

: 1984

Hexagon Head Bolts, Screws And Nuts of Product Grade C

CurrentFrequently UsedSpecificationBIMStructural Engineering · Fasteners, Bolts and Anchors

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This standard specifies the dimensions and technical requirements for hexagon head bolts of product grade C in the size range M5 to M36. These fasteners are widely used in general engineering and structural steelwork where high-precision tolerances are not strictly required.

Specifies requirements for hexagon head bolts, screws and nuts of product grade C.

Quick Reference Values

size rangeM5 to M36

product tolerance gradeGrade C

typical property class4.6 (as per IS 1367)

Practical Notes

Product Grade C indicates wider manufacturing tolerances and rougher finishes compared to Grades A and B, making them economical for standard clearance holes in steel framing.

Always specify the property class (e.g., Class 4.6) along with this IS code for procurement to ensure adequate mechanical strength.

Part 1 specifically covers bolts (partially threaded shank). If fully threaded fasteners up to the head are required, refer to Part 2 (Screws).