Clevis

Cotter Pin

The clevis pin is the thing the cotter pin sticks into. Clevis can be about ¼ inch to ½ inch and has a hole neat the bottoms so the cotter pin can go in.

I’m lazy and hook my trailer to the garden tractor with a clevis pin and don’t bother to use a cotter pin to keep it in place.

I think it’s a misunderstanding of terms, which the two previous responders have sort-of-but-not-explicitly addressed.

The “clevis” is the heavy (relatively heavy, but at least proportional to the shackle anyway) pin that closes the shackle. What you may be thinking of as a “clevis pin” is the cotter pin.

I can (and have) substituted a bobby-pin for a cotter pin. I couldn’t (with any hope of it taking the stress) substitute a bobby-pin for a clevis pin. :-)

@CWOTUS: I think the first two posters explained it perfectly…