Andre or BC MIST help please...

[LobWedge]

I've recently picked up a Mercury Tour Pro Kevlar shaft and the raw CPM is listed as 251. Now if you go by Merc's specs that falls in the x-stiff range (I'm extrapolating with Andre's help as the chart only goes to 243 CPM in the upper stiff range and 240 CPM being centreline stiff) based on a shaft length of 46" +/- 0.1"

The issue is, I've discovered my shaft is only 45" long. Based on their method of determining CPM, butt clamp 5" using a 205g cylinder weight with a 1.25" hosel depth, what's my flex, and how much will the CPM differ between 46" and 45"?

Thanks.

[Chieflongtee]

Not much time this morning.However in the meantime I have included 1 link for you to check out.
http://members.shaw.ca/cgdick/irons.xls

More later

[Chieflongtee]

According to a frequency chart I have here with me.(John Kaufman)
251 cpm at 45inches is regular Flex.
260 cpm at 45 inches is Stiff flex.
270 cpm at 45 inches is X stiff.

If you shorten the club at 44 then 251 raw will become approx 258 still a regular flex.
The longer the shaft the lower the frequency and the shorter the shaft the higher the frequency providing all thing being equal.
Makes sense?

[LobWedge]

Okay, now I'm really confused because if I read the chart correctly, 250 CPM at 45" comes out to 7.0 flex (same scale as Royal Precision?) which is extra stiff.

I think I need to find an old fashioned Maltby flex board. My head hurts.

p.s. I used to get work done at Caltec years ago when I lived in Calgary. They came up with the "Bi-Matrix" idea long before TT did.

[Chieflongtee]

Provide a fax number. I'll send you the chart.

[LobWedge]

It's okay, It's just frustrating when one mans x-stiff is another man's regular. There should be a universal standard for frequency matching. I'm gonna go with my gut and insert the shaft to 1.75" and plug the other 1.25", and butt trim to 45". If it ends up being too soft then I'll insert to the full 3" and add an extension to bring it back to 45".

I know that a raw shaft weight of 78g, and a head at 200g with a 52g grip at 45" will get me an "old-world" swingweight between D4 and D5.

Please feel free to offer your opinion. Thanks.

[Chieflongtee]

Okay, now I'm really confused because if I read the chart correctly, 250 CPM at 45" comes out to 7.0 flex (same scale as Royal Precision?) which is extra stiff.

I think I need to find an old fashioned Maltby flex board. My head hurts.

p.s. I used to get work done at Caltec years ago when I lived in Calgary. They came up with the "Bi-Matrix" idea long before TT did.

I am not reading the chart the same way you do. Go to 250 and where the lines meet for a 45 inch shaft you should read just a tad more than 6.0.

[LobWedge]

I'm going to email him for clarification. I'll let you know.

[LobWedge]

Hey Andre. I haven't heard back yet, but I think I see what you're getting at. My shaft at 251 CPM and 45" should flex out at close to 6.2. Based on Merc's formula on their trim guide, I should be able to get a flex of 6.8 to 7.0 with a hosel depth of 3" and a head weight of 200g. Which is in the S/X range I was looking for.

[LobWedge]

Hey Andre. Here's the response from Colin. Just as you thought (and after I sqeezed it in to my thick scull, me too)

"Sorry for the delay in answering, but I have been busy. By my chart, 45" at
251cpm reads as 6.1-6.2 flex, rather stiff by today's general "standard"
where 4.5 is Standard and 5.5 is now rated stiff.

If you read this from a 205 gram tip weight, an actual head weight would be
less, and the cpm would be higher, i.e., stiffer than that. Then again, an
actual head mounted might change the club length, and therefore alter the
indicated flex.

I know not what Royal Precision are doing now. I recollect they originally
did their measurements with a grip on. Very confusing as the grip means
almost nothing.

I published this on my site several years ago, and I still use it myself for
all my clients. It has worked well, as 75+% of my club making business
comes from client recommendations.

American Cubmakers generally used stiffer frequencies than us Canadians. I
have noted many USA based companies have revised their designations downward
to less flex.

Thank you for asking.

Colin"

I think I'm on the right track now. Thanks for your help.

[Chieflongtee]

From what I gather the shaft will turn out to be an in between regular and stiff on my chart. That is not what you want to hear but the honest truth. The dampening effect of the grip makes it 6-10 cpm lower. It does not really matter as from my experience Mercury shafts are far from being whippy.And besides butt frequency does not tell the whole story. The real story comes from zone profiling i.e different readings along the length of the shaft. Zone profiling will tell you the truth about the said shaft i.e butt stiff tip soft or vice versa and etc..Send me a fax number via pm and will gladly send you a copy of my chart free of charge. It is John Kaufman's chart. I bought my frequency meter from him. No standards there either if you know what i mean.