OK, the second verse is ALMOST a repeat of the first, and I've got pictures to prove it.
This is the parts of the first die.
The movable top die is on the left and the base die is on the right. That V-for-victory shaped thing in the middle is the result of the first pressing - IT won. I'm using a Harbor Freight 1/2 ton arbor press to do all the pressing.
This just shows how things went together for the first press.
I modified the base die and the top die for the second attempt. The first dies only had 3 bottom layers, 3 top layers, 3 perimeter walls, and 30% infill - I doubled all of those for the second attempt. The areas that had the most damage on the first dies were where the 2mm rod contacted them as the rod was being forced into a staple shape. The bottom of the top die took a real beating, but the radii at the top of the U-bolt slot in the base die also took a hit. I can't get a decent close-up picture of those areas so you're just gonna have to trust me on that one. Other than upping the wall count and infill, I couldn't think of an easy way to beef up the top die. The bottom die on the other hand was easy. I used steel, in the form of a pair of 1/4"-20 bolts. I punched a pair of holes through the base die, so that the outside of the bolt's shank replaced the radius in the slot for the U-bolt.
This is the parts of the second die, and the results of the second press.
I have the beginning of a squared off U-bolt going on there. The top die still took a beating, but not nearly as bad as the first time. If I make the top die out of steel I should be just about there. It's a simple piece of 5mm flat stock with a 2mm slot cut part of the way across it - eazee-peasee.
The is the second die set up to press.
Don