Stiffening or weakening A/C/Es without cutting

[Duss]

Just in case you have to stiffen or weaken a set of (expensive) A/C/Es and do not want or cannot cut them or lenghten them (more difficult).

If you are using 100-grain piles wou might have two choices. Using the 120-110-100 cut down to 100 or the full-length 100-90-80.

If you install the full-length 100-90-80 pile you will have a much stiffer arrow than with the cut down 120-110-100 pile and your total arrow length shall be reduced by 1/4" but will still have the same tube length.

The reason is the internal tail length of the insert making the tube stiffer.

 

[Kae]

Might not the pile weight not also make a teeny weeny bit of difference?

 

[Duss]

Sure it MIGHT. But in the example given I was only supposing one would be using the same pile mass, but in a different configuration.

I would like to see a 110-100-90 type of pile weight in the A/C/E series, but it does not exist. I might one day decide to take a dozen of 120-110-100 and machine their business end to make them into 110-100-90.

I noticed that effect one day I wanted to play with my A/C/Es stiffness and I had tried 120, 110 and 100 grain piles, all coming from the same type of 120-110-100 piles. It made almost no difference. The reason was that the change in insert length was cancelling the change in mass.

That may also explain why I have heard many A/C/E users complain that they could not tune their set of A/C/Es

 

[simon m]

What he means is you want bendyer arrows but the piles must be 100grn try the next size up cut down to 100.

less insert means another 1/2 inch of shaft to bend freely.

 

[Duss]

Thanks Simon,

We may also see the same behaviour in X10s with the huge difference in the pile material between the stainless steel and tungsten piles

 

[SLOWHAND]

I've tried it and you are quite right. An 80-100 grn pile at 100grn makes the arrow stiffer than a 100-120 grn pile at 100grn. But it's not just the fact the there is more insert in the arrow with the 80-100grn pile. The external bit of the 100-120 grn pile is quite a lot longer making the overall length of the arrow greater and the FOC greater.
The choice of nock (pin nocks,Beiter nocks, G-nocks) and fletchings can also have a slight effect on arrow tune, the heavier the back end of the arrow is the stiffer it will shoot.

 

[Duss]

Unfortunately a change in FOC, unless huge, would not make a difference in stiffness. In this case the FOC does not change THAT much