Mizuno MP-58 Irons -- The secret is in the forging

By Jeffrey A. Rendall, Images courtesy of Mizuno USA

NORCROSS, GA – Several years ago we took the opportunity to try out the Mizuno MP-60 irons, and wrote of their ‘trophy’ looks in addition to their exceptionally high performance. Some things never change – at least for Mizuno – as their latest introduction to the MP line, the MP-58, is just that much better in the company’s ‘game enhancement’ category, and still has the looks that players will proudly want to show off to their friends.

A golf club’s appearance in and of itself won’t help you get the ball in the hole, but it will inspire a certain degree of confidence if your mind tells you that it looks better because it’s higher in quality – and therein lies the difference.

At Mizuno, the secret is found in their patented forging process, which is a story onto itself. Luckily, Mizuno’s Chris Voshall (Golf Club Engineer, Iron Design) was available to help shed light where before there were only shades of wonder, and mystery: “Of course we’re not alone in the forging world – forgings have been around since the beginning of golf. But what sets us apart is a patented process which we call grain flow forging.”

Upon closer look, each of the MP-58 irons has ‘grain flow forged’ stamped on the hosel, so there’s an indication right there that Mizuno wants you to think about it.

Voshall continues with his explanation: “When a standard club head is forged, you take a billet of steel and literally just pound it into shape. At Mizuno, we do a stretching and bending of the steel before we forge the head into the billet. Picture a six inch by one inch billet of steel -- we then stretch it out so it’s longer, and insert a pin in it which will simulate where the hosel will be placed. That way, we know that the grains are going to go from the toe all the way up to the hosel – so it’s going to give you the maximum amount of consistency in the head, and the greatest feedback.”

That’s not all. “Not only is our process more consistent in terms of grain structure, it’s more consistent in terms of flash,” Voshall added.


Flash is the excess material that is squeezed out and polished off during the forging process. By working the billet pretty well into the shape of a golf club before the club head is pounded out, the flash itself will be very uniform, and it’ll produce the same amount of flash from one head to the next. The more ‘standard’ pound-it-out forging process will end up with more flash coming out of the toe or the heel of the billet – hence a greater amount of variation from piece to piece.

Consistency translates into the type of feel and feedback that players who pay for high-end irons have come to demand.

The MP-58 irons have thrown a new twist into the Mizuno manufacturing process, however – incorporating a new titanium insert into the club head (called Dual Muscle Ti) – Mizuno’s first multi-material iron product.

Again, Voshall explains the difference. “In the MP (game enhancement) line, we try to keep everything in a really small player’s package that has the right look, and we do everything we can to make sure it has not only the right look, but the proper feel also. That’s something that’s kept us from going into the multi-material irons concept prior to now, because the way multi-material irons have been put together in the past, they’ve sacrificed in the feel department.”

Voshall continues, “With the MP-58, we developed a way to insert a small piece of titanium into each club head and still come out with a 100% forged iron – it’s not welded on, and it’s not glued on, and there’s no foreign material. The titanium is literally pressed into the head, and based on the cooling (how titanium cools and contracts versus how stainless steel cools and contracts) process – it’s mechanically locked in.”

“It allows us to make a multi-material iron that keeps everything the MP line stands for – we keep the grain structure of the head, and the irons feel great – while also enjoying the benefits of multi-material, which essentially means it’s the most forgiving club that we can possibly make in that size package,” Voshall instructed.

Basically speaking, the multi-material process allows for more weight to be transferred to points in the club head that ‘need’ it – so off-center hits won’t be as punishing as they would be otherwise. The MP-58’s will still feel the same as other grain flow forged clubs in the Mizuno line, but they’ll be even easier to hit – which opens up the MP line to more levels of players.

Voshall says the MP line is designed with the preferences of better players in mind, but its new performance characteristics are friendly to mid-handicappers in addition. It’s the same dual-capability goal that other manufacturers have set as well, though haven’t necessarily been straight with consumers on what the new product represents: “A lot of the manufacturers are offering what they call ‘Tour’ clubs, while the product they’re selling isn’t even close to what the Tour guys are playing – and the clubs are often not what a good player wants to look at.”

“Their so-called ‘Tour’ clubs are still somewhat oversized, have lots of offset, and they’ll say they’re ‘Tour’ irons to try and lure you in to buying them. With the MP-58, we don’t give up anything that a scratch golfer wouldn’t want – we’re not playing that game, making huge, more forgiving clubs and calling them a ‘Tour’ product – because we know the better player knows the difference,” Voshall added.

So how does the new ‘Dual Muscle Ti’ process translate into more feel? Just follow the grains.

“Our process allows us to control how the head is going to vibrate, so we know we’ll get the feedback a player needs to see -- you know, ‘what went wrong on that shot, what to correct, what to work on.’ I wouldn’t exactly call it a training aid, but the feel you get with our MP-58 irons lets you know what you’re doing on every shot. It doesn’t hide anything in the golf shot, good or bad,” Voshall said.

‘Feel’ is a hard thing to put into words, and it’s true, you’ll have to hit a good many golf balls with any iron to really develop a sense of what goes ‘wrong’ on a mishit – but I found that the MP-58 is as good as Voshall’s promise. Forged irons have always felt the best – and when you hit one well, there’s no better feeling in the world of golf.

But it’s after playing them for a number of rounds where you’ll see the distinction, whether it’s a bit off the toe or on the heel, or even as Johnny Miller would comment ‘a bit high up on the face.’ The MP-58’s provide the feedback that Voshall was talking about – and it’s a nice thing to have.

As far as choosing the right irons for you, Voshall says it’s all about trial and error. “I think the consumer just needs go and try stuff. The proof’s in the pudding when you actually hit the clubs – and usually when people hit Mizuno irons, we come out on top.”

There’s also Mizuno’s Performance Fitting System (PFS), where you can try any of the company’s iron heads with all the shaft options, right on the spot. Mizuno also offers a shaft optimizer, which measures your head speed, tempo, release factor, toe down and kick angle – all within three swings. The compilation of data provides a recommendation on the best head/shaft pairing for you.

As you’d probably expect from a complex new manufacturing process, it took years to find the right combination of titanium weight and depth (distance from the face) to employ in the MP-58’s. “That was something that wasn’t decided until the end,” Voshall remembered. “We’d literally made clubs with several different combinations of titanium weight and depth – because they’re all going to feel a little different. We took them all out to the guys on Tour and received feedback on what they liked best – and the number we settled on was eleven grams of titanium set 2.9 millimeters from the face. It was that precise.”

With all that goes into them, there’s no doubting that the MP-58’s are a fine product – and we’d highly recommend trying them if you’re in the market for a high-end iron. They’re not inexpensive, but you’ll notice the quality the moment you lay your hands on them.

At that time, you’ll clearly realize, Mizuno’s secret is all in the forging.

Note: The MP-58 irons conform to the new groove rules for 2010.




Mizuno MP-58 Irons

Inquire at your higher-end golf retailers and club pro shops. Available in right and left hand with True Temper Dynamic Gold S300 and R300 steel shafts and Golf Pride M-21 58 Round Grips. Custom combinations are available as well.

Check out more information about Mizuno Golf products at: www.mizunousa.com.

Note: Mizuno has also introduced several other models of irons that merit a look – you can find them on the website.

Mizuno USA, Inc. is a wholly owned subsidiary of Mizuno Corporation, one of the largest general sporting goods manufacturers in the world. Mizuno USA, Inc. manufactures and distributes golf, baseball, softball, running, track & field, and volleyball equipment, apparel, and footwear for North America. Mizuno USA, Inc. is based in Norcross, Georgia.

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