To start, we should clarify that working load, also known as chain pull, and tensile strength are not the same. Working load describes the amount of linear pull exerted on a chain by a drive while tensile strength is the amount of force required for that chain to fail. While these measurements can be related, the two terms are not interchangeable.

For drives operating at speeds lower than those shown in Diamond’s horsepower ratings charts, chain pull, in combination with tensile strength, can be used to select the appropriate roller chain. Here are several equations used to determine working load or chain pull:

Generally, chain pull should not exceed 1/6th of the ultimate, or maximum, tensile strength for chain with press-fit connecting links or non-offset links or 1/9th of the maximum for slip-fit connecting links or offset links. By comparing chain pull against rated tensile strength, the appropriate chain can be selected.

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