I then placed a piece of wood lengthwise along the intended fold and proceeded to give it a few delicate taps with the hammer - nothing. Hit it a tad harder - a lot of springback and a tiny little bend. And so the first bend progressed very slowly, all the time making sure that the tab wasn't bending out at the tips but right around the corner defined by the bending blocks. Soon the first tab was bent and a quick inspection revealed that not only did it look good, but there were no crack and the bending blocks hadn't budged at all!
Without touching anything I continued to bend the next tab upwards. This bend went a tad faster and soon the outboard tabs of the trim tab were bent and looked great to me. Released the tension on the clamps took everything out and swapped it all around to bend the inboard tabs. These being slightly longer bends, I double checked my bending block alignment and again cranked down on the clamps until I physically couldn't make them any tighter.
In no time at all, both outboard tabs were bent and I had the trim tab in my hands and was surveying my handiwork in detail. I made one or two minor adjustment by hand as I was holding it, just to get the opposing tabs to lie flush with each other.
In retrospect, it was actually fairly easy. All I used was a block of wood and a hammer - no rivet guns with mushroom sets, nothing like that. I do think that a lot can be said for a decently shaped building block that has been aligned properly. I also feel that clamping it down really tight so that it cannot move at all and doing both tabs on a side prior to releasing it from the clamps minimizes your chance to messing it up!
This would also be the perfect place where "The enemy of 'good enough' is 'better'!" Meaning that when it's bent, it's bent - don’t go messing with it to try and make it better or flatter or crisper corners - you're more than likely courting disaster!
Gads! The trim tab tabs are done and they look great afirst time round! :D
Inboard tabs - first bend complete
All Trim tab's tabs bent! - yeehah!
Inboard trim tab edge lined up with elevator after the bend
