"Crenelations"!
I knew there must be a name for those ridges but never knew it. That's awesome, i'm going to try and use it in conversation today!
Black frog, the top opener on your last pic has an awesone ridge along the outer side of the loop, how did you get that?
I've seen jigs that bend on thebias, but if that were the case, and you bent a square bar, you would have 2 ends at the handle, but that opener looks like it was a bar you drifted to get the loop.
How did you actually do it?
I like the diagram. If I see it right, you think about 3/4 from the tab grab on the cap surface is right?