I'm hesitant to post, so bear with me.
I took Kent's class last year with my son. We had a blast, but one goal with aircraft parts is I need to shape them by shrinking. Stretching is much easier, but the metal keeps getting thinner.
I dived in, but soon realized my ortho doc would be making a whole bunch more money on me. No longer 18, but at 55 have had enough joint issues that I avoid repetitive injuries. I can swing a hammer for an hour, but that is about it. Very little progress in shrinking that way.
Practice piece (smaller portion of that nose bowl in the back ground, just to get the hang of it).
Tuck is formed by bending, forming a peak, and the sneaking up on it from both sides. That is a small tuck, I did some huge ones and kept thinking I would make a mess of things.
About two hours (I'm slow, and still have lots to learn). It just felt good to be able to shrink something, and not have to reach for something for pain and swelling. I'm about due for another knee, but if I can keep shoulders, elbows, and wrist from damage.... that Air Hammer will pay for itself in a short time!
edit: sheet metal micrometer. Started at 0.040" -- about 0.044" around the edge. It varied 0.042" to 0.045".... still pretty interesting, bowl is only done with that one die set in the photo. It was worked quite a bit, but haven't annealed it.
bowl_shrink2.jpg
bowl_shrink.jpg
bowl_shrink3.jpg