Cutting off of the back increases spine more than cutting off of the front, with X10's even more than ACE's. If you look at X10's you can easily see how thin the back of the shaft is vs. the middle. On an ACE you have to try harder but you can still see it.
Since there is a lot of flex in the back of an X10, when you cut from that end it dramatically increases spine.
No, I don't remember any of my posts with such content.
Anyhow, cutting X10 on the back was quite common for compound shooters to get the right (stiffer) spine from their shafts, usually from 410 and 450 basic spines.
Then, Easton has introduced Pro Tour shafts, that are a kind of "pre-cutted" X10, and so I have to suppose that compound shooters now can avoid any ... cutting activity
From the technical point of view, shafts shot from a compound bow withstand the maximum poundage on the second half of their lenght, so the spine of the second half is dominating for grouping consistency . If this part is made stiffer, the entire front part tend to react like it was the point, generating an effect that is similar to an improved dynamic FOC for the arrow.
So, during release, arrow cleans the bow like a very short arrow with a very heavy point, adding to this the fact that a stiff second half has less oscillations on the horizontal plan. Benfits are immediately evident by any way of tuning...
If you had an arrow that was on the weak side, (X-10), and you had .5" to play with in length, you would stiffen the arrow to a greater degree by taking the .5 off of the back compared to the same .5 off the front. The reason is the back is weaker than the front so by cutting off the weaker side it stiffens the arrow to a greater degree.
Hope that helps. Jay Barrs used to do a great discussion on the subject.
I called the tech department at Easton and they were VERY helpful when I got my first set of X10s last year. I knew that the 470 spine of my ACEs was abolutely perfect, but the X10s only came in 450 and 500. The guy told me to cut 1" off the back and 3" off the front to end up at the desired arrow length and get a 470 spine. He was dead on and they tuned perfectly first time out. If I had not trimmed the inch off the back I would have had to make the arrows too short before they got stiff enough.
Ok, the time has arrived. The reason to cut the back of X-10's as previously noted is to stiffen the shaft more than cutting the front.
I have another solution. X-10 points with a longer shank going up into the arrow. This effectivly shortens the working arrow length stiffining it.
They are in hand and pictured on another post.
Anyone want to see a shot of the finished product?
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