Greetings. I've been building rods for just over a year now. I've got a few under my belt. I build inshore saltwater spinning and casting along with fly rods for both salt and fresh (trout in NC). I build for myself, friends and family. As one of those people that likes details and data I have started to work with the Common Cents System. I've built myself a fixture for supporting rods in a repetitive manner and followed the details as explained by Dr. Hanneman and several folks here who have commented on the process in the various threads I've researched and read. I'm here frequently using the "search" function. I almost always find plenty of info on something I'm trying to figure out. I have a question about results from my testing today that I would like the experts to chime in on. I tested about 20 rods today, mostly completed, both customs I have built and some of my favorite factory rods. I have a few blanks on hand that I have yet to build and I tested a couple of those as well. My current measurement method is IP (in grams) and AA using the chart supplied in a PDF. Frequency is something I'm considering but am still working on a method I can employ. So (sorry for being so long winded) here is my question.....

I have a blank and I also have a finished rod I built from that same blank. I tested each today to determine IP and AA and expected there to be a difference between a raw blank and a finished rod. What I didn't expect was a difference of about 9%. The two blanks (one raw, one finished) we are talking about are classified as "Medium" power (I'm aware that's a bit useless but I mention for clarity). They are 84" long. The finished rod is built as a spinning rod with titanium guides, Alps MVT reel seat and Forecast carbon fiber split grip. Both rod blanks were supported at exactly the same location from the butt (10% of total length). The finished rod has a 9% higher IP than the raw blank. The AA's were the same. I guess in reality I have two questions, is a finished rod going to have a higher IP than a raw blank? What would be considered normal/acceptable variation between two of the exact same rod blanks if measured prior to building? Unfortunately I don't have two of same blanks in my inventory to test my own question with. It was also my understanding that adding guides to a rod makes it less "stiff". I assumed "stiffness" would have a negative effect on IP. Hoping for some comments about IP variation and thank you for reading and/or commenting.

Something is amiss - the finished rod will always have less power/stiffness than the naked blank. You cannot add components to a blank and make it more powerful.

So, my question is, are you comparing measurements from the raw blank, and the same blank once built? Or measurements from two different blanks (same model), one naked and one built? If so, there is your answer.

Obviously, AA will not change between the rod and the naked blank.

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Reading your post again it seems you are comparing a naked blank to a finished rod built on another blank of that same model. If this is the case, be advised that rod blanks are not precision machined parts. There is a great deal of hand labor involved and no two blanks are likely to be identical. Even butt and tip sizes vary by a bit within blanks of the same model. The better the quality control, the less difference there will be, but there will be a difference.

Therefore, your finished rod was more powerful/stiffer before you built it into a rod. You just didn't measure it prior to building it. If you had done that, you would have seen a reduction in the power measurement.

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Yes, measurements from two different blanks (same model), one naked and one built. Sorry I didn't make that clear. I bought 2 of same at same time. Built one and haven't built 2nd one yet. Tested each today, twice (because I thought "this is weird"). Couldn't understand why so different.

I have same scenario in Medium Light flavor (same mfg as those above). One built, one not built. I tested the raw blank today. Tomorrow I'm going to test the built one. I'll post those details then.

So I'm correct in saying that if I had two naked blanks (same model) and tested them and their IP varied by more than 5% that would be unusual?

During testing today I did have a different manufacturers blanks, again medium power, one built - one naked and they tested within <1% of each other (again the built one had higher IP than naked by very slight amount). I assumed that variation was "reasonable" even assuming adding guides would lower the IP a bit.

As I gather more data and get more experience I'm certain this will assist me in making better blank choices and recommendations.

It would be almost impossible to predict how close any two blanks of the same model will be in power and action. The better the quality control, the closer they will be. Many of the top level blanks won't show more than a 2% difference among blanks of the same models. Others will be much more than that.

Power/stiffness and speed will ALWAYS be lowered by the additional of components and guides. You cannot increase blank power/stiffness by adding components. Prove it to yourself by measuring the same blank in naked form and in built form.


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I tested the built "medium light" finished rod this morning. Comparing it to the raw blank that I have (exact same model) from yesterdays testing, I have a difference in IP of 4%. Again, the finished rod has a higher IP than the raw blank.

I concur that adding components to a raw blank will lower power/stiffness, speed and in turn IP. Based on that, the difference in IP of these blanks would actually have been greater than 9% (medium) and 4% (medium light) had I done my testing when all blanks were in raw form (prior to build). Since I was new to rod building I had not yet put a high enough priority on testing with CCS. That won't be the case as I move forward.

Tom, thank you for your expert advice and this place. It expedited my learning curve immensely.

When you are doing a CCS analysis on the a finished rod, the handle will put the blank slightly higher in your rod jig vs a naked blank. Thus the possibility of getting a higher IP number, because you now have to bend the rod slightly more to get to the same point. Another possibility, is that the finished rod’s handle is more tightly held in your rod jig vs the naked blank. So it’s possible the rear of the naked bank may slightly raise when the tip is being loaded giving a slightly lower IP. Error can be introduced in a number of different ways, it just a matter of keeping the scientific measuring error as low as possible. With all things being equal, a finished rod should have a lower measured IP than the unfinished blank, just because more weight has already been added.
Norm

The two blanks weren't identical to start with, even though they were the same model.

Next time you build a rod, measure the blank before and then after it's built. I think you'll find the finished rod will be a tad less powerfull-stiff than it was before you built it.

Something else I'm going to mention, and it refers to the set up when taking these measurements - you are leveling the butt of the blank/rod and not adjusting for any tip droop (and there will be some simply from inherent blank weight). The instant you add a tip-top and guides, the tip droop is going to increase as the weight on the blank has increased. Again, you do not adjust for this as the CCS needs to measure it as well. So now when you add weight to obtain the required deflection, it will by default now require less weight to reach the proper deflection distance than it did with the naked blank. So power (IP, ERN or whatever you want to call it) will be less.

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it looks like there may be 10% variation built into the measuring procedure alone..lol..just funnin'..

You can get that much variation with a bathroom scale or tape measure, if you're sloppy....

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Ben you are right, there certainly can be variations every time you do the measurements even on the same blank. Granted not a lot, but you can get different results, depending on how the measurements are taken. For example, Are you exactly at the 10% support point every time, are you perfectly level, are you reading the bend at exactly 1/3 the length, how secure is the butt in the rod holding jig, etc. A lot of things can change slightly to give variations. Plus or minus a few percentage points can be assumed to be experimental error. When measuring different blanks of the same model the variance may be even greater, due to sight differences during the manufacturing of individuals blanks. I tend not to get anal about small variations as long as I know I’m in the right ball park.
Norm

"are you reading the bend at exactly 1/3 the length"

This one has me a bit worried. Just to clarify - you are not deflecting the blank to a point that is 1/3rd of its length - but rather deflecting it downward a distance equal to 1/3rd of its length.

I'm pretty Norman is doing this correctly but want to clarify for others. I have known some to think it relates to a measurement point 1/3rd of way back from the tip.

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Tom, 10% is a real good day for me..yesterday i glued a DPSM handle on a rod that already had the spin guides in place but "forgot" line the handle with the guides..i remembered an hour later..luckly the guides were off about a quarter turn and i was still able to turn the seat back..in this hobby there is so much of the human element that 10% variation is perfection..lol..Norman, like you i do CCs to get a ball park figure..lately working on bow and arrow rods i can quickly assess a blanks power at certain lengths..it,s a tool even with my built in variations..lol.

I deflect 1/3 the total length of the rod as stated in the CCS articles. Hope this clarifies. The point I was trying to make is that even when you know how much deflection is required for the 1/3 total length defection, a small difference in the angle of you vision, ie, looking down or looking up, can give a small difference In the measurement, vs looking at it perfectly level. Much like looking for the miniscus of a liquid in a tube, looking straight on gives a better reading.
Norm

Norm - All valid points, concerns and things I tried to address when building the jig and getting repeatability built in to my system. I built my jig with modified 1.25" diameter dowels creating a cam type system to be able to "lock in" either a finished rod grip or a raw blank. I've been pleased with it's performance. Did my best to keep error issues minimized. Thanks for chiming in, I read all your posts you've helped me a lot.

Tom - Understood on blank to blank variation. I was aware of the tip drop issue and measured accordingly. As far as measuring blanks before and after....I guarantee it.

Ben - I tried to avoid that but maybe you're right :).

Appreciate the feedback.

I am at the 10% support point every time (without being completely anal). I have butt location marks on my jig for 78", 84" and 90" rods/blanks (my common rod lengths). I'm as perfectly level as my eyes are capable of calculating when applying the level to the blank just ahead of the foregrip (20 years ago I'd have probably been "more level"). I am deflecting it downward a distance equal to 1/3rd of its length. I'd being willing to say I'm +/- 1/16" on achieving proper deflection. I have pennies in zip lock bags in various quantities and marked. Bags have been weighed to confirm pennies/count weigh what they should. Please know I'm not trying to over analyze the whole CCS measuremnt system. I like it and I plan to use it as I believe it makes me a more knowledgeable rod builder.

sounds pretty good Pete..

Pete, just had a similar experience with 2 recent builds. Measuring IP (in grams) and AA I found a 46 g (about 8%) difference between the two blanks (AA was within 3 degrees). Same model and manufacturer. Measured on blanks with tip on, no hardware. I was a little surprised but figure this may be due to variances in batches. Who knows if they came from the same lot?
Now to open another can of worms, I build on the straightest axis, could hitting the spine on one blank and not on the other account for this much of a difference? Never attempted to measure on/off spine IP but will experiment on next build.

TJB

Norman Miller Wrote:
-------------------------------------------------------
> I deflect 1/3 the total length of the rod as
> stated in the CCS articles. Hope this clarifies.
> The point I was trying to make is that even when
> you know how much deflection is required for the
> 1/3 total length defection, a small difference in
> the angle of you vision, ie, looking down or
> looking up, can give a small difference In the
> measurement, vs looking at it perfectly level.
> Much like looking for the miniscus of a liquid in
> a tube, looking straight on gives a better
> reading.
> Norm

Norman - I'm still not getting this, at least the way you have it worded. The CCS articles dictate that the blank tip is deflected downward a distance equal to 1/3rd of the blank's over all length. So a blank that is say, 78 inches in length, will have the tip weighted until it is 26 inches below the level of the butt. Is this what you're doing?

Pete Rinkevich Wrote:
-------------------------------------------------------
> I am at the 10% support point every time (without
> being completely anal). I have butt location marks
> on my jig for 78", 84" and 90" rods/blanks (my
> common rod lengths). I'm as perfectly level as my
> eyes are capable of calculating when applying the
> level to the blank just ahead of the foregrip (20
> years ago I'd have probably been "more level"). I
> am deflecting it downward a distance equal to
> 1/3rd of its length. I'd being willing to say I'm
> +/- 1/16" on achieving proper deflection. I have
> pennies in zip lock bags in various quantities and
> marked. Bags have been weighed to confirm
> pennies/count weigh what they should. Please know
> I'm not trying to over analyze the whole CCS
> measuremnt system. I like it and I plan to use it
> as I believe it makes me a more knowledgeable rod
> builder.

Pete, Here's an easy way to get the blank level - get one of those inexpensive, short plastic leveling gauges. They are V-notched along the bottom and you can set it on the rod blank just ahead of your forward support and then move the butt up or down as required to get level.

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