MOI matching my clubs

[koonl]

Hi,

I've got a set of clubs that I have built and used since Sept/Oct 08. They are Mizuno MP-60 with S300 shafts, std length/lie. I built them all in the range between D3.5 to D4, 0.5" apart in length and the 6 iron is my favourite, judging by the shot pattern, how sweet it feels and from the impact tape.

The other irons, especially the shorter ones, were terrible hits at the range and a few coming from the toe or thinning them. I want to experiment with MOI matching but confused on how to do this.

1. Without having access to any MOI measuring device (except for a sw scale), which is the best method: use 1 sw point or the more exact 1.3 sw point with 0.5" standard length difference or the exact 0.4"? Does it really matter if I am a few nths of an inch or fractions out on the sw?

2. My current sw are as follows: 3i (D3); 4i (D4); 5i (D3.75); 6i (D4); 7i (D3.5); 8i (D4); 9i (D4). Heads are between 6 and 8 grams apart. Shafts are constant 122 grams, grips are all 52 grams. Most of the shafts have lead weights in them so I can easily reduce weight if required.

3. If my 6i is my fave club and I use the 1.3 sw difference, per 0.5", then my 9i will be nearly D6 and my 3i will be D2. Does this sound right? My sand wedge is at D6 and I can't imagine using my 9i at that weight! I can tolerate a D2 3i though. Assuming that I am still accurate with the 6i at D3, then the 9i becomes more tolerable but the 3i then drops to D1.

Any comments?

[LowPost42]

Re: MOI matching my clubs

It's 1.3 SW points per full inch, not half inch. That could get crazy, fast.

The two 'roughstimate' ways to do it are to go with 0.5" length changes and 8g headweight changes, or to go with 7g headweight changes and 0.4" length changes.

On a whim I built an MOI Matched set using just a swingweight scale. I went with TLT series 7 lengths and figured out where the swingweights needed to be, per club.

Built them and double checked them on my MOI Speedmatch machine - all clubs were within 1% of the average MOI value (acceptable tolerance).

As for being a couple grams out being a problem or not, please remember every 2g in head weight = 1 swingweight point. So a couple grams out will have you easily at the edge of your spec, if not outside it completely.

But I'd certainly work the swingweights based on your 6 iron if that's the one you're pounding.

[koonl]

Re: MOI matching my clubs

Thanks for correcting me. Yes, I did mean full inch as TW and Tutleman both say, or at least I calculated corectly (0.65pt per half inch).

I'm not sure what you mean in your 3rd paragraph, do you mean that you stuck each club on the scale, and then added/subtracted weight where needed to get to your target sw?

Because the heads were either 6 or 8 grams apart (the world of inconsistencies), what is recommended here? Do I just allow add a few grams for the lighter heads to make it to 8 grams so they are all consistent? I don't have a half-gram scale to be more accurate unfortunately.

[LowPost42]

Re: MOI matching my clubs

You say you don't understand what I mean in the 3rd paragraph, but you seem to have it.

That's basically how you do it - you chuck a grip in the tray, stick the club on the scale, and use 2g per SW point as your point of reference for how much weight to add to the shaft tip (unless you're going with lead tape).

It's probably easiest to go with 8g steps between heads and keep the half inch steps.