Why are cotter pins listed for one size and actually a smaller size. Working on a hay rake and factory size cotter pin measures 5/16", Had new unopend box of assorted pins with one listed as 5/16" but it only measures 1/4", the 1/4" listed size is actually only about 7/32". places the book calls for 1/8" pin what you buy is so loose in the hole you can't see how it can hold up to use without breaking. What do you do to get the actuall size the parts book calls for and fits? I did actually find some 3'16" one place that did fit the 3/16" hole but that was the biggest they carry. I at times need a 3/8" pin but I have been able so far to subistute a 3/8" bolt but cannot always do that due to the head and nut. That new 5/16" is just way loose in the hole that the old 5/16" fit correctly in.