The pin diameters actually used may be based on any standard
series for sizes of bar material provided that the intervals|
between adjacent sizes do not exceed the R20 Interval (1.12) The next size above the minimum pin diameter, D min as
given in the above table should be used.
The Nominal diameter D used is then subject to the tolerances specified in 5.2 of IS:6132 (Part I). 1971
The eye outside diameter then becomes twice the nominal Pin Diameter
D subject to the tolerances in 5.2 of IS:6132 (Part II) - 1971.
Specification for Shackles : Part I General Requirement for grade 30, 40, and 63 only.
Shackles of Grade 30, 40, 63 confirm to I.S.I specification 6132