When I was about 5 or 6 my dad would occasionally take me to work on Saturdays to the shop he and and his partners had that made Danish modern furniture. A couple of guys would come in on Saturdays to upholster chair seats/backs for them and they were paid piecework. They would lay the fabric or Naugahyde on the bench, put a layer of batten down, followed by some foam and then a plywood seat. They used a magnetic tack hammer to take furniture tacks from the box and put them in their mouth. The tacks were sorted with the tongue and spit head first on to the magnetic tip, the hammer spun and driven into the fabric. When they had a few in they would drive any still up into the seat with the nonmagnetic face. They started at the centre and tacked in several tacks, then spun the seat around and did the same to the bottom that was now at the top while pulling the fabric tight. Spin the seat a quarter of a turn and tack in the centre and spin the seat again to do the opposite. They spread out from the centres tacking and pulling as they went. The corners were done with a tack in the centre and then more pleats and tacks outward until meeting the already done areas. Pleats got extra tacks to flatten them. Excess was trimmed and a layer of black fabric with the edges folded under and tacked on to hide the seat fabric fastening. The entire process from start to finish may have taken a bit longer than 5 minutes each. They didn't talk much while they worked.