When wrapping wood posts with sheet metal how do you close the seams?

https://www.hunker.com/12471154/how-to-wrap-a-4x4-porch-post

You will either need to rent a bending brake for aluminum, or do the bending yourself (harder). If you choose to do it yourself, you will need: a 24" or 48" long straight edge (a good level will work), bending pliers available at Home Depot or perhaps Lowe's with the long attachment for longer applications, heavy duty work gloves and of course, the aluminum. Keep a good pair of straight metal snips for finish cutting. You can fold over a 5/8" seam (like in sewing), and then nail them down with aluminum nails that match the color of your aluminum being used. If this is for below ground installation like a fence, I usually heavily coat the posts with a motor oil to prevent rot. Good luck. I hope I've helped with the information you provided. If not, write me back . . . .

Was described as the hemming and seaming process. A link attached for your information. Suggest you check youtube for videos on sheet metal projects. You can inquire from a sheet metal supplier for proper tools. Hope this helps

https://en.m.wikipedia.org/wiki/Hemming_and_seaming

Screw the seam closed right into the wood

Thanks. Nails were used not screws. Is that why there are gaps?