A blog reader said that he watched the Mizuno Optimizer video and wondered what they meant by ‘hard stepping’ and ‘soft stepping’ a shaft?
I’m not exactly an expert on club making and repair, but I’ll give my best shot.
TYPES OF SHAFTS
First, we need to understand that there are 2 different types of golf shafts, ‘parallel’ tip and ‘taper’ tip. The main difference in these shafts is their tip diameter.
The ‘taper’ tip has a smaller tip diameter of 0.355” compared to the bigger tip diameter of the parallel tip shaft which is at 0.370”.
However, there are some other differences in these shafts as well.
PARALLEL TIP (0.370 tip diameter)
Shafts do not come in their length and the clubmaker does not just insert them into the club, puts a grip on them and gives them to the golfer. Instead, let’s say you want to replace a 37.75” shaft in a 5-iron of yours with another 37.75” shaft. When you order the shaft and get it in the mail, it will come in at a length much longer than 37.75”. For instance, KBS Tour parallel tip shafts come in the mail at 43.5” long.
From there, you trim the shaft down to the desired length by trimming the butt end of the shaft.
The thing with parallel tips is ‘one size fits all.’ So if you want a parallel tip KBS Shafts…one for a 3-iron and one for a 9-iron, you would basically get the same shaft. You would get 2 shafts that are both 43.5” long and then you would just cut the shaft from the butt end to the length you want the club at. So if your 3-iron is 39” long and your 9-iron is 36” long, you just cut the shaft from the butt end to those lengths.
TAPER TIP (0.355 tip diameter)
With taper tip, you do not get the ‘same shaft.’ The shafts will still be much longer than the shaft you play with in the club. For instance, a 9-iron may have a shaft length of 38” long. But the 3-iron may have a shaft length of 41” long. In essence, each club has its own shaft to accompany it. So if you are looking to purchase a taper tip shaft for your 3-iron, you need to order a 3-iron taper tip shaft. If you are looking for a taper tip shaft for a 7-iron, you need to order a 7-iron taper tip shaft.
SHAFT WEIGHTS AND LAUNCHES
Part of what we need to understand is that stiffer shafts tend to weigh more. For their taper tip version, KBS Tour regular flex shafts weigh 110 grams. Their stiff flex weighs at 120 grams. And their X-Stiff weighs at 130 grams.
For their parallel tip version, the regular flex weighs at 120 grams and their stiff and x-flex weighs at 130 grams.
Back in the 90’s and before that, when OEM’s started to really mass produce clubs, shafts were a big problem because their Quality Control of determining the flex of the shafts was dependent upon just weighing the shaft. If their stiff flex was supposed to weigh 120 grams, they’d weigh it and if it measured at 120 grams (or close to it), they’d mark it a stiff flex, even if in reality it was a very weak or very stiff shaft. These days the QC for golf shafts is much better.
Also, a stiffer shaft will typically launch the ball lower than its weaker shaft counterparts. So, if you have a True Temper Dynamic golf R300 (regular flex) and a X100 (x-stiff), the X-100 will launch lower and weigh more.
HARDSTEPPING AND SOFTSTEPPING
Hardstepping and Softstepping is done with taper tip shafts. Hardstepping makes the shaft for that club a bit stiffer. If I hardstep a 6-iron one time, that means I’m putting a 7-iron shaft (a shaft that is stiffer) and putting it in a 6-iron. Conversely, if I soft step a 5-iron once, I’m making it a weaker flex and thus putting a 4-iron shaft (a shaft that has more flex) into a 5-iron.
HARDSTEPPING/SOFTSTEPPING ONLY POSSIBLE WITH TAPER TIP
Like I mentioned, you can only hardstep and softstep with a taper tip (0.355 diameter) shaft. Remember, the taper tip shafts are the ones that have a specific shaft for each club.
Thus, when we hardstep a 38” 5-iron. We are putting the 6-iron shaft in and still cutting it to 38”.
Let’s say we get a 5-iron and 6-iron taper tip shafts in the mail and they are both X-Stiff flex. The 5-iron may come in the mail at 39” long. And the 6-iron shaft may come in at 38.5” long. Let’s say we want to hard step a 5-iron once with the X-Stiff shaft, even though the 5-iron and 6-iron shafts are the same flex, because the 6-iron shaft is shorter it will naturally ‘play’ a bit stiffer than the longer 5-iron shaft.
You CANNOT hardstep or softstep parallel tip (0.370 diameter) shafts. The main reason is that parallel tip shafts come in the mail at the same length whereas taper tip has that variable length.
WHY DO WE HARDSTEP/SOFTSTEP?
Hardstepping and softstepping is done mainly to get ‘in between’ shaft flexes. Let’s say that you are prescribed to soft step S300 True Temper Dynamic Gold Shafts one time in your irons. What that is trying to do is give you a shaft that is between True Temper’s S300 (stiff) and their R300 (regular) shaft flex. I believe the general rule of thumb is that 1 time hardstep/softstep will change the flex by ½ (somewhere in between shaft flexes). And if you hardstep/softstep twice, that changes it by 1 entire flex (so a S300 shaft hardstepped twice will now become like a X100 shaft).
But there are other reasons for doing this as well.
Since stiffer shafts typically weigh more and launch the ball lower, we may use that to our advantage.
Let’s say we want to soft step a KBS X-Stiff shaft two times (for example, putting a 3-iron shaft into a 5-iron clubhead). What will happen is:
1. The shaft will effectively play like a Stiff Flex instead of an X-Stiff flex.
2. The shaft weight will be somewhere between what a stiff flex and X-stiff flex play like.
3. The shaft launch will be somewhere between what a stiff flex and X-Stiff flex play like
WHY ARE THERE PARALLEL TIP SHAFTS AND HOW CAN YOU ALTER THE CHARACTERISTICS?
Parallel tip shafts were mostly a design of OEM’s so they could more easily and more cost effectively mass produce the iron shafts. Instead of having to ‘customize’ a shaft for each iron, they could just create a shaft that would fit into all iron heads that have the diameter for it. Also, if you have a taper tip clubhead, but a parallel shaft, you can always have the head drilled to 0.370 diameter and fit the shaft in. I have a 5-iron that I practice with that I had drilled to a 0.370 diameter.
With parallel tip shafts if they want to alter the flex, they will ‘tip’ the shaft. Tipping the shaft is when they cut the shaft from the tip end. You can do this with parallel tip (0.370 shafts). However, you cannot do that with the taper tip shafts (0.355) because the club will not fit into the head of you try to tip a taper tip shaft.
So let’s say you have a 5-iron you want re-shafted with a KBS parallel tip shaft and you want it tipped ½” with a total shaft length of 37.75” long.
Parallel tip KBS shafts are 43.5” long. So you would cut down ½” from the tip end (which now makes the shaft 43” long) and then trim the shaft down to 37.75” from the butt end of the shaft.
Some clubmakers prefer parallel tip shafts because you can more precisely measure the frequency needed by tipping a shaft over hard stepping/ soft stepping a shaft. One of the ways to measure this is thru a shaft frequency machine.
The frequency machines measure shaft flex by shaft ‘vibration.’ They will have the club go up and down and then measure the ‘cycles per minute’ (cpm). The higher the cycles per minute, the stiffer the flex of the shaft.
IIRC, a shaft that measures at 300 cycles per minute is considered stiff. At 310 cpm you are starting to get into the X-stiff range. At 290 cpm you are in the regular flex range.
So clubmakers feel like they can tip a parallel tip shaft and more easily get the cpm’s where they want it.