Spine consistency between "models" and brands?

[HenrikBP]

If I find a suitable spine in one brand/model, will I still be close to correct spine if I go with the same spine in a different model from the same brand or the same spine from a different brand?

I just got a Morrison bow: ILF 17" riser with "D" "Long" recurve limbs in glass and foam core for an overall length of 62".  45# at my 26 3/4" draw length.

I bought a test set of Trad Only arrows in 600, 500 and 400 spine plus a screw-in point test kit. I don't know that I want to shoot Trad Only arrows, but it was the less expensive kit and I figured I'd be out less $$ if I buggered it up        

With the 400 spine shaft at 29.5" BOP, a 200 grain point and a regular aluminum insert the arrow shows slightly weak spine - but it's close. I need to install string silencers and limb tip protectors before I do the final tweaking

So if I went with say ICS Hunter shafts in 400 spine, I should be able to build a similar arrow that should fly about the same - right? I figure that's the case but would prefer to avoid a costly "assumption".  

Thoughts?

Henrik

[saumensch]

In my experience, only different models from the same brand are comparable in spine.
(I say comparable because even if they have the same static spine, different weights, shaft thicknesses or finishes may have affect on dynamic spine)

Different models from different brands may vary quite a lot.

For example:
Out of my Bob Lee the Gold Tip Exp. Hunter 7595 was flying perfect in my configuration, so i tried the Ted Nuge shafts from Gold Tip in 7595 and i had to leave them a little longer to get the same results. I assume the little higher weight made them dynamically stiffer.

For me, when i change model OR brand its back to bareshaft every time, more work, but leavs the guessing work out.

[RUTANDSTRUT]

static spine and dynamic spine are two different animals.  if you have two brands of shafts both at a .400 static spine but slightly different diameters, they will have a different dynamic spine which determins your tune.  i shot the trad only shafts last year which are made by easton which had a very consistent spine per dozen, good shafts.  if you have a shaft that tunes good and want to try a diffeent brand, i would recommend using the stu miller dynamic calculator and build the other arrow to the same dynamic spine, has proven to be very accurate.

[HenrikBP]

Thanks guys, that all makes sense. That difference in "build" will alter dynamic spine.

I did play with Stu Millers calculator, and there was a ± 2 lbs swing in dynamic spine between various models and brands.

If I go with different shafts, I would go through the same process of bare-shafting with different point weights and gradually shorten the shaft until I found the right spot.

But I guess that as long as I leave myself a bit of "wiggle room" length wise, I should be able to tune a variety of shafts of similar spine to shoot well out of my bow.

Thanks again for your help,

Henrik