After attempting to put a shackle marked 5/8 into an 11/16 hole, I am now left wondering WTF the stampings mean. I know when I see 3/4T on one that is the load rating. What do the other numbers mean??

Help me out here....WTF are you talking about?:confused:

The cross-section size of the D-part and the crosspin are not the same (usually not, anyway).
Chris

The 3/4 (or 5/8) is the diameter of the "D" part, not the pin. A 3/4" screw pin anchor shackle has a 7/8" pin; I'd suspect that a 5/8" shackle has a 3/4" pin. But it depends on the style of shackle, too.