I know alot of people who float their arrows in a tub to find the spine. They cork the ends then mark the high side.

Does it work? Beats me! I think tru-flite does something along those lines. I am not sure about that, but I do know that many top archers order their arrows from tru-flite, so however they build them must work pretty good!

NRA,UBP,BASS Member
New Stanton,PA

I also used to float test my arrows. After I found out about the bearing test, I did it both ways. The float test may or not show the same weak spine as the bearing test. Mostly not. I believe Tru-Flite finds the weak spine also. By what means, I'm not sure.

I thought that a weaker spine was basically just an arrow with thinner walls making it weaker than an arrow with thicker walls.Are you guys saying that every arrow has one side weaker than the other?

To be honest I have tried this and it dosn't produce any better flight then when I didn't. the only reason I do it is to make my broadheads nice & neat in my foam quiver insert! <img src=icon_smile_big.gif border=0 align=middle> I think what happens more often than not is that the insert was a litt out of whack & by turning it it got seated better which yielded the better flight.

Just in case you might want to align your broad heads with your vanes, it is pretty simple. I use a small amount of pipe tape until they align. I couldn't tell you one way or another if it helps.....I'm just a sucker for the tiny details <img src=icon_smile_blush.gif border=0 align=middle> Scott

jsasker...when we say weaker I'm not refering to the strength of the tube itself. I'm refering to how much it will flex. The answer is yes, each arrow will flex more one way than another way. This test is to determine this. Example....fishing rods. Take a cheap fishing rod and whip it back and forth. You will notice that the tip will start out by going back and forth, but if you keep it up for a second or so, it will start to make a circle. The spine is fighting your whiping action. If you do that to an expensive rod, your whip will just stay back and forth. There is a machine they use to indicate the spine of the fishing rod and match the parts accordingly. The same thing happens with your arrow. You have pressure on your arrow from your nock, release and rest. As you release, your arrow flexes. If you don't make the weak side of the spine of your arrow the same (top or bottom for release shooters) you arrow will do the same thing as the cheap fishing rod, it will flex irradically until it is stabilized. Now granted it isn't going to make any difference to the hunter shooting 15-20 yards wanting a heart or lung shot (large kill area). But it does make a difference to the 3D or target shooter. The x's are a lot smaller. Just makes your groups smaller.

After putting a little thought into it, you can tell if the bearings are showing the &quot;weak side/s&quot; of the spine OR the curve of the arrow (all arrows have SOME curve...even if it's only .001&quot
find the weak side of the arrow using the bearing test.
Now turn the arrow 180 degrees. and retry the test. if the arrow moves, you have found the curve. if not, you have found the weak side (better word might be plane) of the arrow.
each arrow I have tested (cx 3-d selects) have shown the bearing test to show the &quot;weak side of the spine&quot; to be the curve of the arrow. Even on arrows at LESS than .001&quot; I was not able to find an arrow that showed a weak spine on any side that would show up on the other side (180 degrees).
Again, this was only with cx carbon arrows...others may be different.

IMN23D, I was thinking a bit (kinda scary), sometines when I paper tune I get some weird results, especially at the six foot test. I use what some people call excessive weights on my tips (175 grain) with long arrows (33&quot, so arrow flex off the bow is pretty important. Do you think that since I have never done any off the tests that you suggest, that I might be getting an inconsistant initial flex off the bow that is showing up on the paper. I am going to try your tests and see if I can get the initial flex off the bow at least consistant. BTW clearence is not a proplem at all.

Stealth.....Not sure I agree with your assessment. I have an Arizona arrow straightner that I made a 32&quot; channel for. Now, when I do my straightness check on my arrows (CXL 250) the high or low side (bend), as checked with the dial indicator, is not in relation to the bearing test weak side (plane, I like that term better too). So, that tells me that it is the weak spine plane reading that I'm getting.

BobCo...I believe that if you match your arrows, you will get a consistant reading. They may not be the correct reading your looking for (depending on if the arrow is correct spine in the first place), but it should be consistant.