Leaf chain dimensions chart per ASME B29.8. A leaf chain consists of a series of link plates assembled with pins in such a way that the joint is free to articulate between adjoining pitches.
Chain Numbering: The chain carries the prefix BL. The digit at the end of chain numbering designates the number of link plates in the articulating pitch. The digit to the left this designates the number of plates in the pin link pitch. The digits to the left of those two digits denote the number of eighths of an inch in the chain pitch.
General Chain Dimensions, in.