Pile weight vrs Spine Values

[ASW1973]

sorry probably did not make it clear: you alter point weight for groups not to tune.So for most people they would never alter the point weight as they can not shoot the groups required (ball park figure 310 and over recurve and 340 and over compound at 70m for gents)

[Dreadnaught]

A man whose opionion I respect (GMB in his time) once told me on ACEs 5gn equals lb1.4 + or - on draw weight I've never tried to test it though.

[geoffretired]

If you put heavier piles in an arrow I was told you make it bend more(appear softer) as the point has more inertia, so is less inclined to move when the string starts.
But with the extra weight to move, the string travels more slowly and a slower string makes an arrow appear stiffer. It would seem that puts you back where you started but with a lower sight mark.

[Dreadnaught]

What you say is pretty much what I have always thought to be so. Perhaps I did not word it very clearly, the point is, if you add 5gn to the point weight the arrow will bend exactly the same ( all else being identical) as if the bow was lb1.4 heavier draw weight.

[Dreadnaught]

I think your point about being back where you started is true to some degree but the arrow bend increases with heavier points at a faster rate than the string slows down. Sort of 3 steps forward 1 step back.

[Jerry Tee]

Download the Easton 2006 shaft selector program, use the hunting selector and you can change the point weight and see how it affects the spine .

[geoffretired]

Dreadnaught, I have been told that the amount of bend is not so important as the rate of bend. Unless the heavier pile has a much longer stem, the rate of bend of the shaft remains the same( rate as in frequency, yes?) The rate of bend determines what attitude the front of the arrow is in as it leaves the string. Is it left or right of the string line, or actually on line. A stiffer arrow will have bent one way and back the other more quickly that a soft arrow. Fast enough in fact, to be over to the left for, I think, the second time at the front if too stiff(R/H archer) A soft arrow will have bent left then right and not had time to get back left again so flies right ish. Slowing down the bow for that slow arrow means it gets back to the mid point in the slightly longer time it is given by the slower bow.

[BasicNigel]

Soooo.... what happens with 'break off' piles.
Your reducing the lenght of the insert, making the arrow spine weaker (I think) and reducing the pile weight. Don't the two cancel each other out ?

[geoffretired]

Basic Nigel, break off points don't quite work like that. Break some off the insert and the arrow that bends, is longer, so weaker. The arrow is also lighter so travels faster. The faster the arrow, the faster the bow; faster bows make arrows appear weaker.That's two increases in weakness; both small. That's one reason why some archers use them to match their arrows to their bows.

[wingate_52]

Thus you can have 2 break-off points, one with a heavy protruding point but with a short shaft making the arrow behave slighly differently from a point with the same overall weight with nothing broken off and having a longer shaft stiffening the arrow.