DIY MOI MATCHED IRONS - OEM order - Custom play lengths from 5/16" to 10.7 mm between clubs

If you have a set where the #9 works just perfect, or is about to order a OEM set, but would like to have it MOI matched and to Custom play lengths, here is the charts for you.

**NEW OEM Sets for DIY MOI**

Order the set to classic FLAT SW value and 4/8" between clubs as usual, where you focus on specs for your #9 iron on play and SW value. Order the set with grips loose in the box.

When you get the set home, you cut them shorter progressively by 2.0 mm from the #8 and longer. if the set is 3-PW your #3 iron becomes "1 club shorter", and SW progression WITHOUT reset of head weight becomes 1.1 SW pr inch, or very close to a Actual Moi match of 1.33 SW pr inch. (see the chart in the bottom)

This way we combine a progressive slope very close to actual MOI, and slightly easier long irons to play since both length and resistance goes down. This way the player who could not handle his #4 iron can squeeze that club in, or the player who could not handle his #3 iron makes room for that club. If you already play 3-PW you make room for a Driving iron you can handle.

Compare of standard 4/8"(12.7 mm) vs 10.7 mm vs 3/8" (9.35 mm)

Starting from #8 makes a slightly longer set vs stating from #8

So, just order the set to what ever specs needed for the #9 iron and the same FLAT SW value for all - Then butt cut 2.0 mm progressively like the chart, add grips on, and get out to play. I cant be much easier than that, NO head weight replacement needed, except maybe the PW.

Then you get a set thats very close to MOI matched (closer than 4/8" with 0.5 SWP between clubs), NO reset of head weight needed, and you get improved ball striking all the way to the longest club who gets about 1 club shorter than standard. This way we can modify a iron set to give us "1 club shorter in" and that club will be easier to play then the one you had of the same play length.

If you want to go 3/8" and "poor mans MOI Match", we can do the same. Focus on specs for your #8 or #9 irons, order the set as 4/8" with the SW value your #8 or #9 should have, butt cut and ADD the grams needed you find in this Chart. (Lead tape or Tungsten powder), Add grips and play.

**LIE ANGLEs?**

The longest club might need 0.75* more upright (if its 6/8" shorter, the clubs thats 4/8" shorter up with 0.5* etc) 1/8" shorter = 1/8 of 1.0* , 2/8" shorter = 2/8 of 1.0* in sets where standard is 0.5* between clubs).

Example for use of the chart.

You play a #9 iron thats plus 0.5" from standard, and standard SW value was D2 as "std play length", so thats club should be D5 now. The specs for a set with a #9 thats plus 0.5" is equal to using a "std" #5 iron as starting point (look at those lines)

If the #9 is your favorite club, and everything is just fine with it, order the set as plus 0.5" with a flat SW value of D5, and _Butt cut like it was a standard set using the #9 iron row as stating point.

BUTT cut like this when you order 4/8" with Flat SW value, and use your #9 as Stating point.

All values is "relative to std and D2 as standard", so staring point does not matter, just make sure that club is the favorite, and base the specs on that club.

The example set with a #9 thats plus 0.5" at D5 as starting point.

**How to figure out if this is the way to go for YOU?**

If your #9 is your favorite and the club we wants to Duplicate so the others get the same actual resistance, grab your longest iron and "tape down" play length like that suggested shortening was already done, add the suggested amount of lead tape to the head, and try that club off. The way it feels and plays now is as close as we can get without actually cutting it shorter. For 10.7 mm sets, we dont need any weight added, so if your #3 is the longest, "tape it 12 mm shorter (12,7 mm is 0.5"), and try that club off, and if its the #4 thats the longest, tape it down 10 mm and test it, and compare it directly to your #9 to feel if they are a "good match" or equal effort to swing so we can use the same power and swing on both.

ALL MODS AND NUMBERS is based on Classic 4/8" sets with FLAT SW value for all clubs in the set. If you order without grips and cut at home, you have a easy job to build what ever you like based on standard components and sets ALL OEMs can deliver.

Just make sure you base the order on the specs for your #9, then you can go 10.7 mm or minus 2.0 mm pr club - , 9.70 mm or minus 3.0 mm pr. club - 3/8" (9.35 mm), or 8.7 mm who is minus 4.0 mm pr club - or 5/16" (7.93 mm), you have tons of options, based on a uncomplicated order to OEMS if you can cut and make SW values right yourself.

**Here is 5 CUSTOM option for MOI Matching, all set ups based on the #9 iron. Both butt cut instructions and grams needed to reset head weights to a slope of 1.33 SWP is done for you. You can make all of them based on a "regular OEM order" with loose grips. **

I'll just add to Howard's excellent post, that there's an assumption that the shafts are constant weight. So make sure to select a shaft set for your order that is not descending (flighted) or ascending in weight (as the clubs get shorter).

Although ascending weight shaft sets make it easier to build MBI matched irons set (not just MOI matched), the jury is still out on how AWT shaft sets change the recipe for creating a pseudo MOI matched set. It's highly dependent on the weight increment between the shafts.

> @Noodler said:

> I'll just add to Howard's excellent post, that there's an assumption that the shafts are constant weight. So make sure to select a shaft set for your order that is not descending (flighted) or ascending in weight (as the clubs get shorter).

>

> Although ascending weight shaft sets make it easier to build MBI matched irons set (not just MOI matched), the jury is still out on how AWT shaft sets change the recipe for creating a pseudo MOI matched set. It's highly dependent on the weight increment between the shafts.

We can choose what ever shaft and weight progression as we like, it does not matter.

Descending weight becomes less descending and closer to Constant WGT. Constant weight shafts become "slightly Ascending", and Ascending weight sets MORE Ascending, but not by much.

The differences to balance point does not matter when we do the math for head weight replacement since they are all relative to the SW value of the #9 iron. If we shorten a Descending, Constant or Ascending wgt shaft by 6/8" we loose the same amount of SW points to be replaced, and at the same "new play length", its the same number of grams needed to get SW on the wanted slope. Total WGT will move some, but not much..almost nothing and more for Descending wgt than for Ascending wgt.

The club with largest changes is the #3 iron so here is how that looks as shaft weight loos from 6/8" butt cut and replacement of head wgt.

Hi Howard this is an awesome chart. I recently put together a set of maltby TS1 irons based on MOI forum posts you’ve done but I missed this part...

For the poor mans MOI match based on the #8 iron and 3/8” increments, I assume the weight addition per head in your chart is based on the heads being properly spec’d at 7g increments? So moving from 8i to 7i would be the 7g difference and then add the additional weight indicated in your chart?

Sorry if that’s an ignorant question. And thank you for always sharing your knowledge!

> @offwhite said:

> Hi Howard this is an awesome chart. I recently put together a set of maltby TS1 irons based on MOI forum posts you’ve done but I missed this part...

>

> For the poor mans MOI match based on the #8 iron and 3/8” increments, I assume the weight addition per head in your chart is based on the heads being properly spec’d at 7g increments? So moving from 8i to 7i would be the 7g difference and then add the additional weight indicated in your chart?

>

> Sorry if that’s an ignorant question. And thank you for always sharing your knowledge!

Not ignorant at all, its a very good question actually..

This specs is only as good as tolerances from OEMs, so if we get a set thats off specs...they will still be off if we dont correct them, so its not really set matched with 7 grams heads (only in theory), but to the same SW value what ever weight progression that gives on the actual set.

Desceding wgt sets needs more head weight in the short end vs the long when we build them, so no sets is 7.0 grams flat on slope, its "the average" in the sets who is 7.0 grams, but that number might vary a little depending on shaft choice. BUT from that stage (build by OEM to flat SW), modifications and needed reset is equal for all since we navigate in SW values who vary in grams pr. SWP depending on play length.

This charts navigate in "relative numbers" vs SW value for the favorite club, and play length differences with corresponding weight adjustments needed for those play lengths and target values.

We can use the #8 or #9 as start, that does no matter, just move the headers 1 step to the left, so #8 becomes point 0, and you have all numbers except the 'PW, but PW remains unchanged on play when we start from #8, but we need another 1/8" play length on the #9 if we go that way. if 4/8" above standard on the #8 is starting point, order the set plus 5/8" plus so the #9 comes in at full play length.

If you wants to use the charts starting from the #8, we must add 0.5 SWP on target value to get that #9 who is 5/8" plus correct.

The #8 will then fall back on slope when we cut it 1/8" as the first club, and we add about 0.7 grams only to that club.

typos in chart..new coming up

What's the preferred way to add a small amount of length to a club? Like 1/4" or 3/8"?

Won't normal shaft extenders add too much weight?

Thanks!

@Howard_Jones - thank you for post this, very much appreciated. i was wondering how you cut shafts to this level of precision. for graphite shafts with a pipe cutter, i could see getting close. but with graphite iron shafts, seems like there would be a lot of room for error in cutting shafts precisely enough. 

Mark the shaft as precise as you can using a THIN pen
...(check how the club lies on the ruler several times).

Cut on "the long side" of the cut mark so there is a little left over....

GRIND down to target....check measurement during that process to make sure you dont overdo it

Club making shall NEVER be like you worked in a Chinese factory, clean the place, make it nice, tools where they shall be, and take your time and enjoy the process, thats how to make good clubs with tight tolerances.. 

For steel shafts, pipe cutters is good, for Graphite we should use a fast rotating disk, be it a Dremel type or what ever type with a thin FAST rotating cutting disk.

NEVER try a pipe cutter on graphite if you dont have a Dremel or similar, then you should use a fine blade hand saw, and some tape around the shaft, CUT MARK ON THE TAPE - CUT TROUGH the tape. Its to prevent a carbonfiber to be pulled free from the shaft if the saw blade catch it instead of cutting it, so a saw blade not fine enough, can ruin a graphite shaft. The tape is extra precautions taken against that (use colored plastic electric tape like electricians use on cables, not grip tape for golf)

5 hours ago, Howard_Jones said:

Mark the shaft as precise as you can using a THIN pen
...(check how the club lies on the ruler several times).

Cut on "the long side" of the cut mark so there is a little left over....

GRIND down to target....check measurement during that process to make sure you dont overdo it

Club making shall NEVER be like you worked in a Chinese factory, clean the place, make it nice, tools where they shall be, and take your time and enjoy the process, thats how to make good clubs with tight tolerances.. 

For steel shafts, pipe cutters is good, for Graphite we should use a fast rotating disk, be it a Dremel type or what ever type with a thin FAST rotating cutting disk.

NEVER try a pipe cutter on graphite if you dont have a Dremel or similar, then you should use a fine blade hand saw, and some tape around the shaft, CUT MARK ON THE TAPE - CUT TROUGH the tape. Its to prevent a carbonfiber to be pulled free from the shaft if the saw blade catch it instead of cutting it, so a saw blade not fine enough, can ruin a graphite shaft. The tape is extra precautions taken against that (use colored plastic electric tape like electricians use on cables, not grip tape for golf)

Thanks, yes I have a 6" chop saw with a grinding wheel type blade (no teeth). I also have a rod saw without teeth as well which i can use by hand. I guess i need to be as precise as possible to make the cut between 3/8" and 4/8", but error on the long side and grind down. 

@Howard_JonesJust so I'm on the right track. Using the 3/8" slope, we start with the 9 iron and adjust the SW until we find the weight we like best, then we can go to the longest club, tape it down and add the recommended weight, test it, adjust weight as necessary to get the longest iron to feel the same or consistent strikes. From there we can develop a slope of weight to add to the rest of the set.

I will say the 9 iron isn't my favorite, but I have my set at d2 from 5-9 iron. So I believe I can love the 9 iron if I spend time playing with the weight. 

1 minute ago, kjbuckeye said:

@Howard_JonesJust so I'm on the right track. We start with the 9 iron and adjust the SW until we find the weight we like best, then we can go to the longest club, tape it down and add the recommended weight, test it, adjust weight as necessary to get the longest iron to feel the same or consistent strikes. From there we can develop a slope of weight to add to the rest of the set.

 

I will say the 9 iron isn't my favorite, but I have my set at d2 from 5-9 iron. So I believe I can love the 9 iron if I spend time playing with the weight. 

You got it right, but if you dont like the #9, what club in the set does feel right?
The issue will be that the "other club" what ever club that is, will most likely be modified / cut shorter, and then it want feel like it did, but we can get it back, so if one of the other feels good now, i can reverse the numbers so you instantly get the weight adjustment needed for the #9 so you can try it off and decide if that "other club" is the one to duplicate resistance from, even if play length will be adjusted.

59 minutes ago, Howard_Jones said:

You got it right, but if you dont like the #9, what club in the set does feel right?
The issue will be that the "other club" what ever club that is, will most likely be modified / cut shorter, and then it want feel like it did, but we can get it back, so if one of the other feels good now, i can reverse the numbers so you instantly get the weight adjustment needed for the #9 so you can try it off and decide if that "other club" is the one to duplicate resistance from, even if play length will be adjusted.

I will say that my 7 iron is most comfortable because that is a club that was always used during practice sessions growing up because it was the "middle" of the set. But I can't say that I love it compared to the rest of the set. I believe it will be best for me to dial in the 9 iron and go from there.

26 minutes ago, kjbuckeye said:

I will say that my 7 iron is most comfortable because that is a club that was always used during practice sessions growing up because it was the "middle" of the set. But I can't say that I love it compared to the rest of the set. I believe it will be best for me to dial in the 9 iron and go from there.

No problem at all, if you want the resistance from the #7, simply add 1.33 SWP on the #9 if they are both the same SW now. Then your #9 would have the same resistance as your #7 got.

For a 36.00" #9 iron, 1 SWP is 2.26 grams so 1.33 SWP is 3.00 grams.....its that simple
Try that, and you will at least get silly close to whats right for you.

I decided to go 3/8" between my new set of 921 HMP's.  I also decided to start with my 9 iron and so far it's been unbelievable. I doubt I will ever own a traditional 1/2" set again. Thank you Howard for all of the information on the board. It's been outstanding. 

How do you decide on the slope? Just by what the golfer would prefer length wise, using the tape down technique?

30 minutes ago, roarkerandall said:

How do you decide on the slope? Just by what the golfer would prefer length wise, using the tape down technique?

Just remember the ONLY everlasting rule in Club tech and fitting............WHAT EVER THAT WORKS THE BEST....

So...we always have to do some trial and error, we should not make decisions based on "paper specs", but give them a try real life like i suggest, so we know for sure its the right way to go for us on THIS set of clubs.

Im not sure if ive added the link to my METRIC Excel VBA app here, but here it is, and its using the #8 iron as BASE or "point zero"
Here you can play around and see what options you can build, and what mods it takes to get there as but cutt and head wgt adjustements.

This 2.0 version is made for MODs of existing sets, but can be used for "projects" and builds to for those who knows how we can use the numbers we get in return for that.

Please READ the first post before you jump to page 2 and scroll down to find the latest post from me where you can download the app