For a long time, the steel shaft was only used by good players and professionals. Steel is a relatively hard and heavy material and therefore only advisable for a certain club head speed. Today the reality looks a bit different. Some steel shafts have become extremely soft and light. So light that they are an option even for players with lower club head speeds. If not in the irons, then at least in the wedges. A carbon shaft has the disadvantage that it will always be softer than a steel shaft and therefore has corresponding twists that you want to avoid. Especially when it comes to precisely playing a flag.
One would like to think that the quality of steel shafts cannot vary so much. However, this is not correct. Also with steel shafts there are big qualitative differences. Imagine, for example, you as a club maker get a set of iron shafts to build an iron set. The shafts, however, vary 10% in weight. This makes it more difficult to build a high quality iron set with correct and constant swing weight. Therefore we can only rely on high quality iron shafts that have a reliable weight and are accurate to the gram. Most often we use shafts from Japanese manufacturers like Shimada and Nippon. In our opinion, these are unbeatable in terms of price/performance.
The classic steel shafts that we use in iron are above all: