A month ago I did a build and got a DBI of 16/77 and a URRS of 16/8/35 for a particular blank.

Today I'm starting a new build on a new blank of the same model but got a DBI of 19/76 and a URRS of 19/9/47.

I used the same process but the resulting measurements are somewhat different. I've measured a bunch of blanks but this is the first time I've measured different blanks of the same model. I would expect perhaps some small variation in the numbers, i.e. the AA is 77 and 76. But the ERN and PR are quite a bit different. I build on the straightest axis so when I measure the bow is down and the ends are up.

Is this common for blanks of the same model? Would I accept the most recent measurements for that model going forward when recommending a blank to a customer or would it be better to average out the measurements. In this case an ERN of 17 or 18 and a power reserve of 41?

Thanks,
Chad Huderle

Huderle Custom Rods
Prior Lake, MN

Assuming you were diligent in your measurements, and it sounds like you were, then there are a couple of possibilities. First, the manufacturer may have changed that model's target specs. It happens. The makers are always trying to improve product by tweaks and upgrades. That could be the case here. Then, there is always the case that one or the other blank was mis-bagged/mis-labeled. Or, the maker trimmed it improperly from the mandrel. A half inch this way or the other can make a huge difference in power and action.

Rod blanks are not precision machined items. There's a great deal of hand labor involved from lay-up, to trimming to sanding. It would be rare to have all blanks of a specific model come out identical, although with good quality control they'll be fairly close.

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Thanks for the quick reply Tom.

My main reason for doing these measurements is to recommend a blank for a customer who brings me one of their existing rods and wants something faster/slower or heavier/lighter than what they bring in. I suppose averaging the numbers may help me get closest to what they're looking for...then I can adjust from there.

Thanks,
Chad Huderle

Huderle Custom Rods
Prior Lake, MN

I understand. The measurements are what they are - you can't fool the CCS any more than you can fool a tape measure, so you'll have to try and figure out why there is so much difference between those blanks. I'd talk to the manufacturer and ask if they've made any changes to that model.

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Chad, I use blank measurements along with this to visually show customers blank characteristics - [www.backlashtools.com]

Chuck

(Actually, I built my own before this came to market)

_________________________________________
"Angling is extremely time consuming.
That's sort of the whole point." - Thomas McGuane

Chuck, that tool would really fit the bill for what I'd like to do. Thanks for letting me know about it!

Thanks,
Chad Huderle

Huderle Custom Rods
Prior Lake, MN