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IS 1363:2002 Part 1 is the Indian Standard (BIS) for hexagon head bolts, screws and nuts of product grade c - part 1: hexagon head bolts (size range m 5 to m 64). This standard specifies the dimensions, characteristics, and designation of hexagon head bolts of product grade C (commercial/black bolts) in the size range of M5 to M64 used for general engineering applications.
Specifies requirements for hexagon head bolts of product grade C, with sizes M 5 to M 64.
! Grade C bolts are widely known as 'black bolts'. They have wider dimensional tolerances compared to Grades A and B.
! These fasteners are primarily used in clearance holes for static loads and secondary structural connections where high precision is not mandatory.
! This standard only dictates dimensions; the mechanical properties and testing (like yield strength and ultimate tensile strength) must be referred to IS 1367.
Direct equivalent covering metric hexagon head bolts of Product Grade C in the same size range.
BS EN ISO 4016:2022BSI (UK) / CEN (Europe)
HighCurrent
Hexagon head bolts - Product grade C
The British and European adoption of the ISO 4016 standard, making it identical in technical content.
DIN 601DIN (Germany)
HighWithdrawn
Hexagon bolts with nuts, product grade C
Historical German predecessor standard for Grade C hexagon bolts, now obsolete.
ASME B18.2.3.5M-2013 (R2018)ASME (US)
MediumCurrent
Metric Hexagon Head Bolts
Covers metric hexagon head bolts, but does not specify product grades; tolerances are generally tighter than IS Grade C.
Key Differences
≠IS 1363-1 is exclusively for Product Grade C, which allows for wider manufacturing tolerances. This contrasts with more commonly used standards like ISO 4014 or DIN 931 which specify higher precision Product Grades A and B.
≠The default mechanical property class specified in IS 1363-1 is Class 4.6. While other classes can be agreed upon, this default is a low-strength grade typical for Grade C applications. International standards for higher grades (e.g., ISO 4014) often default to higher strength classes like 8.8.
≠IS 1363 refers to other Indian Standards for material, properties (IS 1367 series), and threads (IS 4218 series), which may have minor deviations or different revision cycles compared to their direct ISO counterparts (e.g., ISO 898-1, ISO 4759-1).
Key Similarities
≈Both IS 1363-1 and its direct equivalent, ISO 4016, are specifically intended for general purpose engineering applications where precision is not critical, hence the focus on the economical Product Grade C.
≈The fundamental geometry, including the hexagon head shape and the calculation for thread length (b) for a given nominal length (l), is identical between IS 1363-1 and ISO 4016.
≈The designation system is consistent. A bolt is specified by its name, standard, nominal diameter, nominal length, and property class (e.g., 'Hexagon head bolt IS 1363 – M12 × 80 – 4.6'), which mirrors the ISO designation methodology.
≈Both standards use the standard ISO metric coarse pitch thread profile as the default, as defined in ISO 261 and ISO 68-1 (which IS 4218 is based on).
Parameter Comparison
Parameter
IS Value
International
Source
Tolerance on Nominal Length (l=100mm)
±3.1 mm (Product Grade C)
±0.43 mm (Product Grade A)
ISO 4014
Tolerance on Width Across Flats (s) for M12 (Nominal 18 mm)
-1.0 mm (s min = 17.00 mm)
-0.42 mm (s min = 17.58 mm, for Grade A)
ISO 4014
Default Mechanical Property Class
Class 4.6
Class 4.6 (but other classes like 8.8 are more common for Grades A/B)
ISO 4016 / ISO 4014
Standard Size Range (Nominal Diameter)
M5 to M64
M5 to M100
ASME B18.2.3.5M
Thread Length (b) for M16 x 100mm Bolt (l ≤ 125mm)
38 mm (formula: 2d + 6mm)
38 mm (formula: 2d + 6mm)
ISO 4016
⚠ Verify details from original standards before use
Key Values4
Quick Reference Values
Minimum nominal thread diameterM 5
Maximum nominal thread diameterM 64
Product gradeGrade C
Typical property class4.6
Tables & Referenced Sections
Key Tables
Table 1 - Dimensions of Hexagon Head Bolts
Table 2 - Preferred Lengths and Grip Lengths
Key Clauses
Clause 3 - Dimensions
Clause 4 - Requirements and Reference Standards
Clause 5 - Designation
Frequently Asked Questions3
What is the difference between Grade C and Grade A/B bolts?+
Grade C indicates lower precision and wider dimensional tolerances (commercial finish) compared to the tighter tolerances of Grades A and B.
How do you designate a bolt according to this standard?+
A typical designation includes the name, IS number, thread size, nominal length, and property class (e.g., Hexagon head bolt IS 1363 (Part 1) - M12 x 80 - 4.6).
Where can I find the tensile strength requirements for these bolts?+
Tensile strength and other mechanical properties are specified in IS 1367 (Part 3), not in IS 1363.