You do not need a crimping tool to do this.
How to crimp sheet metal.
How to make the crimp on your ductwork to allow two pieces to fit together.
Use the power of a drill to crimp the ends of metal duct faster and more evenly than crimping by hand.
Just make a solid with the same geometry as the deformed crimped sheet metal part and place it in the assembly.
Anthony hoekstra showing how to crimp snap lock round duct.
Self tapping is the use of self tapping screws to directly tap the thread on a piece of sheet metal so the fit is very good and can be disassembled.
Use on 30 24 ga.
After pickle and rinse i fluxed the ovals and four 2 2 mm crimp tubes on my soldering board.
Hand held sheet metal benders for opening seams.
The pressing rivet process presses the crimp nut or screw against the sheet metal and can be mated with the corresponding outer nut or screw.
I lined up two crimp tubes on the other ends of each oval and soldered them in place with easy solder using a low flame and 0 smith torch tip.
Amazon link to great products that ev.