Raw length of irons shafts are longer than what actually goes into the head.
Soft and Hard stepping is used to build in between flex's, and to raise or lower the ball flight where tip trimming is not an option.
An example of Soft stepping would be to use 3 iron shaft in a 4 iron head, this will make the club play about one third of a flex softer and will raise the ball flight. Using a two iron shaft in a 4 iron head would be a double soft step, or Soft stepping twice and will make the club play about two thirds of a flex softer. Soft stepping thrice would drop the club a full flex from say an R to an A, but will produce a much higher ball flight than you would have received by just going with the A's to start with.
Likewise Hard stepping once would be to use five iron shaft in that 4 iron which will make it play about one third of a flex stiffer and bring the ball flight down some.
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