MOI Matching

Here is how I MOI matched irons using basic household products.

The procedure I followed is outline by Tutelman and I used his guideline for 1.3SW/in shaft. These are the initial measurements, obtained using a kitchen scale, tape measure and metal straw. Club components are as follows: AP2 712 heads, Project X 5.5 shafts, Midsize MCC grips

Coins were used to increase the 7 iron swingweight to 6155 in-g.

While I wait for lead tape to arrive in the mail, I built a ghetto rigged pendulum to compare MOI's

Time data was captured using two cell phones.

The results I got are pretty good.

Appears that 1.3SW/in is a good reference. Once lead tape arrives I will match the rest of my irons in the set.

Does anyone have suggestions on the best way to remove 5-6 grams from a 4 iron T-MB 718 clubhead? This club has a different shaft (AWT tour white) from the other irons so I may just leave it as is.

That’s a pretty cool set up you came up with haha. Hats off to you for the creativity.
as for weight reduction, best bet is to have some metal from the hosel drilled out - meaning you have a drill but use a smaller diameter but than the hosel so the shaft doesn’t fall further into the bore. You’ll need to be careful with this, and unless you have a drill press and carbide bit, you’ll need to find a machine shop to do it for you. @Howard_Jones had a chart in another thread showing how much weight could be removed by drill bit size and depth using the density of steel (I think 7.9g/cm3).
This is the best option that won’t change the appearance of the club because other options are porting the back muscle and/or sole grind, but both remove the finish obviously and will rust, as well as potential playability issues (with sole grind)

Cool, but too complicated for most, and the need for hosel drilling and pulling a few heads might be over and beyond what many would jump into, so there is easier ways to get there. Another argument against it is that the standard club length progression of 0.5" who makes the need for weight reduction in the long end is not very beneficial.

Most players is able to change grips themselves, and a pipe cutter is also easy to handle, so i did the numbers for 5 different set ups we can make that way, and then we also get the advantage of long irons thats easier to play. The chart is based on the #9 iron as point zero, so all we have to do is make a progressive butt cut of choice between the 6 options here, and add the weight specified back to the heads as lead tape. The fastest and easiest dont even need weight adjustments, its only butt cut to target for both play length progression and MOI (10.7 mm slope).

In the OPs case, the 10.7 option should be considered, if #5 is the longest club in the set, it would be 8 mm shorter than now (almost 3/8" shorter), its not a huge difference, but enough to get that club close to the same actual MOI as the #9 iron and no pulling or hosel drilling would be needed, but you would need a set of new grips. This fastest and easiest want get us all the way to 1.33 SWP inch, but to 1.10 so the #6 iron would have a weight 0.5 grams above target or about 0.25 SWP above target. The other day i saw that Club Champion who is rather expensive has a tolerance of plus minus 0.5 SWP so this is actually better than what they deliver.

The 10.7 Options could also be used in combination with a order on a brand new OEM set where we make a Custom order with specs thats "ideal" for the #9 iron and have them delivered with grips loose in the box. On arrival you just butt cut to the 10.7 slope and add grips, and then you have a brand new MOI matched set without seeing a Custom club maker or run into issues with OEM limitations for what they can deliver. If you fit to play 0.5" above std and D4 on the #9, just order all as 0.5" and D4 and butt cut like the chart on arrival.

Sorry if this feels like high-jacking your tread, i just wanted to give you all a easier way to make it, and more options for play length progression who adds another benefit on top of MOI only. The 3/8" option is the most common to use for this, and if #5 is the longest iron, it gives "1 club shorter in" when that club comes to play, a argument often used to buy a new driver, but here we can get it without.

If you look at the chart again for 10.7 , "first iron longer" than point zero needs 0.2 grams....that makes a head weight slope of 7.0 minus 0,.2 = 6.8 grams from head to head if we wanted to dry fit using equal head weight, but the 10.7 option is mostly of interest if you have a standard set in your hands where the #9 (or #8) is your favorite club. Then i suggest the easiest 10.7 option, butt cut only - NO change of head weight. That set want be "dead on" flat MOI, but have a micro progression of resistance, so a set 3-PW will have a #3 iron head thats 0.8 grams above target...most can live with that on a fast and easy mod like this.

Tolerances in general.

We should look at the clubs as "two parts", one is the head with epoxy and ferrule, the other is the shaft with grip and tape.

If we made all heads to the same head weight progression (no matter for what slope), "the other part" - Shaft with grip and tape should as a sum be as equal as possible, and both shafts and grips has tolerances from production, but we use grip wgt tolerance to even out shaft weight tolerance, so if we weight sort the grips, and add them as the last thing we do, we can get both SW or MOI and Total weight of each club right.

Thank you Howard, I looked at the last chart wrong. This all makes a lot more sense!! Thanks for all your help!