The Complete Guide to Chain

7.1.2.1 Chain Slack

The chain slack that you can move by hand (length SS′, see Figure 7.4) should be about 4 percent of the span (length A-B) unless one or more of the following conditions apply:

If one or more of these conditions apply to your operation, make the chain slack (length SS′) about 2 percent.

Figure 7.4 Chain Slack
Figure 7.4 Chain Slack