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Charl Schwartzel’s drilled-out Miura irons: A builder’s perspective



We see plenty of cavity back irons on the PGA Tour. Most of these irons have been strategically designed to position weight and center of gravity to maximize performance. Spotted this week at the AT&T Pebble Beach Pro-Am: a nonconventional set of “cavity backs” in the form of Charl Schwartzel’s drilled-out Miura MB-001 blade irons.

As first reported by’s Andrew Tursky, Charl, an equipment free-agent, bought the irons online, and after tinkering with them (obviously, Charl is a true gear nut), he felt the irons were just a bit too heavy at D6 swing weight and wanted to bring them down to around D3. These number will seem quite arbitrary to some, so to help explain swing weight, we have a short video below

Now, the question comes down to why would he drill out the irons instead of just having the clubs built to his desired spec?

In the case of Miura irons, a company founded in Japan. The iron head weights are heavier than others on the market because Japan spec irons are generally built to shorter lengths than their North American counterparts. The clubheads are noticeably heavier in the shorter irons and wedges (see chart below), which is why we see more holes in the pitching wedge vs. the longer irons.

Since the MB-001’s are a solid muscle design with no badges or weight ports in the head, there is no other way to remove the mass needed to hit a lighter swing weight for Charl—unless Miura was to produce a set heads at a lighter weights by grinding off mass during the final production steps before final finishing.

Head weight specs 3-PW starting at 245g at the 3-iron.

As a result, when built with heavier tour weight shafts (anything 110g or above) and at a standard North American length (37″ – 7 iron, or longer), the clubs will end up being heavier than what would be considered standard swing weight (usually between D1-D4). Let me please point out that in the golf club manufacturing world there are very few standard practices or measurements beyond the USGA ruler and swing weight scale. Although the phrase “standard clubs” is still common nomenclature, it applies very little to the custom club building world. 

Beyond adding mass to the grip end of the club to counteract the heavier weight of the heads, a practice known as counterbalancing, the only other option is to drill mass out of the clubhead (see full video above for further explanation). Charl reportedly did the drilling himself when fine-tuning the clubs and after a few holes got them right where he likes them.

Based on the thickness of the iron muscle and the amount of mass removed from each head (roughly six grams), these holes have no effect on the performance of the irons (but have probably killed any potential resale value on the open market—bearing in mind that last part is tongue in cheek). If Charl wins another major with these, who knows what they would be worth.

Other examples

This process of drilling out mass has also been referred to as “porting,” and club builders have been doing it for a long time. In the case of wedges, porting not only helps reduce clubhead weight, but can also help (in a very, very small way) remove mass from lower in the head to raise the CG. It’s the exact reason Callaway introduced this design feature in the original PM Grind and continues with the design philosophy today in the JAWS MD5.

With Bryson’s wedges being more than 1″ over standard length, weight had to be removed from the head.

We don’t recommend you start drilling holes in your irons and wedges just yet and suggest seeing a professional club builder to help you sort out your specs and get you dialed in. For more pictures of the clubs Charl Schwartzel is using this week, head to the GolfWRX forum: Charl Schwartzel – WITB 2020 AT&T Pebble Beach


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Ryan Barath is part of the Digital Content Creation Team for GolfWRX. He hosts the "On Spec" Podcast on the GolfWRX Radio Network which focuses on discussing everything golf, including gear, technology, fitting, and course architecture. He is a club-fitter & master club builder with more than 17 years of experience working with golfers of all skill levels, including PGA Tour players. He is the former Build Shop Manager & Social Media Coordinator for Modern Golf. He now works independently from his home shop and is a member of advisory panels to a select number of golf equipment manufacturers. You can find Ryan on Twitter and Instagram where he's always willing to chat golf, and share his passion for club building, course architecture and wedge grinding.



  1. craig adams

    Mar 12, 2020 at 12:42 am

    Charles golf game has holes in it. He’s out of the top 200? A golfer as talented as he is shouldn’t have to tinker with clubs. Manufacturers should be throwing their clubs at him. Did his game go sour since moving to PXG? Why do golfers change a winning combination? Look at Westwood and Jiminez; been playing with Pings all their career.

  2. Eldrick

    Feb 20, 2020 at 3:38 am

    Looks like his Gapr low is a glued non adjustable one.

  3. Nack Jicklaus

    Feb 12, 2020 at 1:02 am

    He should have just drilled all the way through the faces like the old “Hammer” driver. Boom!!!!!!!!!!

  4. Ima Fitter

    Feb 10, 2020 at 5:02 pm

    Love it! You don’t need to spend a ton of money on a new set of irons. As long as they are forged and you like the appearance, pre-owned irons can be fit to your swing. Change the loft & lie, change the shaft, change the grips…any qualified club builder can make them work for you.

  5. Benny

    Feb 8, 2020 at 8:02 pm

    Great catch Wrx and article. Charl left PXG a while ago. But truly suprised he couldn’t get a set directly and have them custom grinded. Anyways great details and love the comments fellas.

  6. bob stelben

    Feb 8, 2020 at 3:01 am

    Good video on swing weights. Can you explain tipping of the shaft and the reasons or advantages/disadvantages?

  7. Steve

    Feb 7, 2020 at 3:23 pm

    I thought Schwartzel was a PXG guy? Guess I am mixing up who Parson’s friends are. And I agree….drilling holes in Miura irons is like adding your own touch up paint to the Mona Lisa. To each his own, I guess.

    • Funkaholic

      Feb 7, 2020 at 4:55 pm

      I doubt a pro is bagging those Miuras for status, he is going to play the grooves off of those babies, appearance is for weekend hackers.

  8. Donn Rutkoff

    Feb 6, 2020 at 3:17 pm

    Palmer probably drilled out hundreds of clubs. Tinkering was common. To suit your own swing.

  9. Fergie

    Feb 6, 2020 at 12:33 pm

    Drilling Miuras like that is, well, blasphemy. He should just get it over with and get CB’s.

    • Funkaholic

      Feb 7, 2020 at 4:53 pm

      CB’s are not the same idea at all, he is reducing swing weight, a CB redistributes weigh to lower in the head making raising MOI and them easier to launch.

  10. Mike Cleland

    Feb 6, 2020 at 10:32 am

    I grew up playing D5 S/W clubs with standard lengths. Does any manufacturers make heavy headed clubs or do they just shove weight down the shaft & change the center of gravity. All my clubs are covered with lead tape. Any suggestions?
    PS: I really enjoy your blogs

  11. jgpl001

    Feb 6, 2020 at 3:50 am

    Nasty workmanship on a quality blade

    He appears to be missing the drilled effect of hs old pig’s……

  12. Dennis

    Feb 6, 2020 at 1:28 am

    Do all the pros go for swingweight instead of MOI-Matching?

  13. Gurn

    Feb 6, 2020 at 12:19 am

    Those Miuras need that treatment like a hole in the head

  14. bill bourne

    Feb 5, 2020 at 8:01 pm

    Does drilling out the backs affect the overall thickness spec?

    • JP

      Feb 6, 2020 at 8:32 am

      Huh? Overall thickness spec? What is that?

      • Tim Armington

        Feb 7, 2020 at 7:54 am

        You dont know what a thickness spec is??? Wow.

        • Funkaholic

          Feb 7, 2020 at 4:56 pm

          Ha! This guy doesn’t know what thickness spec is!

          • maroon

            Feb 8, 2020 at 4:32 am

            I know but it has nothing to do with golf 😉

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What GolfWRXers are saying about the best “5-woods under $125”




In our forums, our members have been discussing 5-woods, with WRXer ‘gary3aces’ looking for a 5-wood for between $100 and $125. He’s looking to replace his current “M2 5 wood with something a little easier to hit”, and our members have been discussing the best options in our forum.

Here are a few posts from the thread, but make sure to check out the entire discussion and have your say at the link below.

  • C6 Snowboarder: “Take a look at a used Callaway Heavenwood in the Epic Flash model = pretty Friggen sweet. It is Heaven!”
  • Golf64: “Bang for the buck, hard to beat Cobra, but find Ping one of the easiest to hit off the deck. Since you are limited in the funds dept., maybe an older model Ping 5W would do the trick?!”
  • tilasan1: “G400 7 wood turned down or just use it as is.”
  • jbandalo: “Fusion fairways. Highly underrated, cheap, easy to hit and go for miles.”
  • RyanBarathWRX: “PING G fairway would be hard to beat and easily in price range:
  • “Another vote for the Callaway Big Bertha Fusion. Great stick!”

Entire Thread: Best 5-woods under $125″


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What GolfWRXers are saying about “blending Ping i500 irons with Blueprints”



In our forums, WRXer ‘ballywho27’ has asked for thoughts on combining his current Ping i500 irons with the brand’s Blueprint irons. ‘Ballywho27’ is considering going “i500 in 3-4 iron and blueprint 5-W” and has asked for fellow member’s thoughts on the idea – who have been sharing their takes in our forum.

Here are a few posts from the thread, but make sure to check out the entire discussion and have your say at the link below.

  • jblough99: “I had a combo set for a minute, 3-5 I500 and 6-PW Blueprint. I could not get used to the transition, HUGE difference in looks at address. If I had it to do over I would just go 4-PW Blueprint and maybe a 3 I500 with graphite shaft as a driving, iron.”
  • animalgolfs: “iBlade{5i} – BP{6i-pw}. That’s my combo.”
  • Chunky: “I have i500 4-5 and Blueprints 6-PW. As mentioned above, there is a significantly different look at address. More importantly for me, the i500s are 1/2 to 1 club longer than the BPs (they fly much higher, too). Make sure you account for that added i500 distance when blending lofts or you’ll have a large gap.”
  • howeber: “I’ve done that exact set — 3 and 4 i500 and 5-PW Blueprint. It’s perfect for me since the 3 and 4 are more like a traditional 2 and 3.5. 4 is usually the longest iron I carry, so I like a little extra oomph out of it. At the end of the day though, when I finally tested them vs my MP4s, the Blueprints performed identically, while the i500 launched a little higher (same specs same shafts). Mizzys are still in the bag.”

Entire Thread: “Blending Ping i500 irons with Blueprints”

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GolfWRX Vault: Avoid these 5 club building disasters



It’s never too late to go back to basics, especially when it comes to club building.

Even with modern new club release cycles the do’s and don’ts of building clubs haven’t changed much in the last few decades except for clubs with adapter sleeves and greater amounts of multi-materials incorporated into the design.

With that in mind its time to revisit an article from the GolfWRX Vault from June 2016.


I’ve been fitting and building golf clubs for more than 15 years, and in that time I’ve seen a lot of really poor workmanship—stuff that would make most GolfWRXers cringe. But like anyone who ever did anything new, I didn’t start being naturally good at putting together clubs. It took a lot of time, ruined components, and trial and error to get where I am today.

I believe my attention to detail now stems from the fact that my dad was a machinist by trade, and anytime we ever worked on something together his attitude was to take your time and do it right the first time. My dad’s approach always had an impact on me, because I feel that if you do something right — even when it takes a bit longer — the job is not only more satisfying but also makes things work better and last longer.

The goal with this article is to help WRXers avoid the most common mistakes and assumptions in club building that lead to broken or ruined clubs, as well as real danger.

Over-prepping a graphite shaft

The shaft on the left has been prepped properly. The one of the right, which has noticeable taper, shows signs that layers of graphite have been removed.

This happens far more than it should, and can ruin an expensive new shaft purchase. To prepare a shaft properly for installation, you only need to remove enough of the paint to make sure that the epoxy adheres to the graphite. This is also true for the inside of the hosel.

Be careful to remove residual epoxy, dirt or rust (common with forged carbon steel club heads that have been sitting around for a while), or some type or solvent like the one used to put on grips, as it can cause of bond to break down very quickly. A proper reaming tool, a wire brush and some compressed air (either a small can or a large air compressor) can make cleaning simple, and prevent a golf club from falling apart.

UPDATE: Over prepping specifically applies to shafts that are designed to go into parallel heads and is especially important for 335 shafts with less material at the tip going into drivers and fairway woods. For information on how to properly taper a shaft to go into a tapered head, check out the video below:

Overheating a Shaft When Pulling it

This is what happens to a graphite shaft when overheated.

This is what happens to a graphite shaft when overheated, and the resin holding the graphite sheets together breaks down. It’s not always as noticeable, but if the shaft starts to fray it means the bonds have been compromised and it’s more likely to fail. 

Overheating a shaft when pulling it is another common mistake that can result in ruining a golf shaft. It also highly increases the chance of breakage. There are quite a few methods I’ve learned over the years to remove a shaft from a club head, from heat guns to large propane torches, but personally I find that using a small butane torch with a regulator for graphite offers the best results. It allows a club builder to easily control and focus the heat only where it’s needed. Bigger torches are fine for iron heads, as long as you don’t damage any plastic badges in the cavity or materials in slots around the head.

One of the best advances in club technology has been the invention and mass adoption of adjustable hosels. They not only help golfers adjust the loft, lie and face angle of club heads, but have also greatly decreased the need to pull shafts. So as long as a golfer is staying with the same metal wood manufacturer, they can usually test several different clubs heads with the same shaft, or vice versa — several different shafts with the same clubhead.

That being said, one of the most important tools that any hobbyist club builder should have or have access to is a high-quality shaft puller. It’s a necessary tool for anyone who wants to do repairs and helps prevent damage to a shaft while pulling it. The more linear pressure that can be applied to the clubhead, and the less heat used to break down the epoxy, the better. It makes sure both the shaft and the head are reusable in the future. For steel shafts, you can use a bit more heat, and twisting isn’t a problem. Again, with increased heat, be careful not to damage any of the badging, or permanently discolor an iron head.

Botching a Grip Installation

Using calipers and two-sided tape, you can replicate the taper of shafts to makes every grip feel exactly the same size in your set.

Using calipers and two-sided tape, you can replicate the taper of shafts to makes every grip feel exactly the same size in your set.

This one seems simple, but when really getting down to professional level detail, it is quite important. We ALL have a preference and different opinion of what feels good in a golf grip, as well as different sensitivities. For example, we all have the ability to figure out what apple is bigger, even if blindfolded because over time we all develop brain function to understand shapes and sizes. This also applies to grips. If you use the same grips on your 13 clubs, you could potentially have 4-5 different final sizes depending on how many different types of shafts you use, because many shafts have different butt diameters.

Some shafts have larger butt diameters, while others taper faster than others. That’s why it’s very important to own a quality set of vernier calipers, and know how to properly use them. It’s also the same for putters, since many putter shafts are smaller in diameter. I have lost count of how many times I’ve had people bring me, putters, where the bottom half of the grip is twisting and turning because the installer never paid attention to the interior diameter of the grip, the exterior diameter of the shaft, and how it changed from top to bottom.

Using epoxy that’s doomed to fail

An example of epoxy that although not completely set, is no longer safe for assembling clubs.

An example of epoxy that although not completely set, is no longer safe for assembling clubs.

I’m a bit of a physics nerd and garage engineer, so this is one of those topics that goes beyond just the physical aspects of club building and into the realm of chemistry.

Here comes my nerd-out moment: In the simplest of explanations for a 0.335-inch driver hosel with an insertion depth of 1.25 inches, the amount of calculated surface area the epoxy can bond between the shaft and the head using the internal dimensions of the head is 1.49 square inches. That’s not a whole lot of area when you consider the centrifugal force being applied to a driver head traveling at 100 mph, and then the forces of torque that also come into play when a shot is struck.

In a PERFECT world, almost zero torque is applied to a shaft when a shot is hit on the center of gravity (CG) of the club head, perfectly aligned with the center mass of the ball, while traveling in the intended direction. This is vectors 101 of physics. Unfortunately, almost every single shot is NOT hit like that, and this is where the epoxy bond is put under the most amount of stress. Lap shear strength of epoxy goes beyond me, but it proves that building a golf club is not just cut and glue after all.

Note: For those of you curious, the most popular epoxies are rated for 4500 psi. 

As far are actually working with epoxy, first things first. Always check to see if the epoxy has a best-before date (yep, just like milk). Also, never store epoxy in direct sunlight. If you are using epoxy from a tube in a dispensing gun, you are using what is an almost foolproof method. Plunge out the necessary amount, mix for about a minute (mix! don’t whip), and remember, the less air that gets into the epoxy the better. If air gets in and the epoxy cures with bubbles in it, then you end up with a club that will often “creak.”

For those using two parts in larger bottles, the best way to ensure proper ratios is to pay attention to the weight ratio rather than volume. This isn’t arts and crafts; it’s chemistry, so by using the weight to calculate the ratio you will get the right amount of each part every time, and help decrease the risk of failure down the road. If you have mixed a larger batch and plan on building quite a few clubs at a time, you really have to pay attention to the consistency and viscosity as time goes on. You don’t want to glue a club head with epoxy that has started to set.

Turning an Extension into a Shank

The difference between a good shaft extension (bottom) and a bad one.

The difference between a good shaft extension (bottom) and a bad one.

This is one of those subjects I don’t even like to talk about. I very much dislike using extensions when building clubs, especially clubs with graphite shafts. Going back to my “do-it-right-the-first-time” mentality, extensions are a Band-Aid fix to a problem that requires surgery. They also counter-balance the club, and by their very nature create a weak point because of the small wall thickness at the butt end of a shaft. The only clubs I don’t mind extending on a regular basis are putters since they are never put under the same level of stress as a club being swung at full speed. I also never extend a club more than 1 inch, because I have been witness to horror stories of clubs that have been overextended that not only break but rip through the grip and cut people’s hands very badly.

If you are going to extend a club, it’s important to make sure the fit is very snug and doesn’t cause the extension to lean in any direction. It’s also best to have the epoxied extension cure with the club on its side to avoid an excess epoxy from running down the shaft and breaking off and causing a rattle.




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