crooked rear taper

[Pack]

I built a taper jig similar to one I saw on this site.  It uses two pieces of aluminum angle attached to a board with 12" files hot melted to the aluminum.  I chuck the shafts up in a drill and feed them into the files.  It works pretty well and has put a 9 or 10" taper on several dozen shafts.  

What I don't understand is why it seems like after I taper them, about half or more of the shafts seem to be crooked on the tapered end and are stubborn about being straightened.  Is it maybe because the get heated up during the tapering process?  Or maybe it is because it files the tapers against the grain?

I wouldn't even bother tapering them except I swear they shoot better (at least when they are straight).  I have even tried hand sanding them so that the jig only does the final shaping and it seems like about half of them still come out crooked.  Has anyone else had this experience or maybe knows why this is happening?

Thanks,  

Patrick

[arrow flynn]

someones kid gets to the targetfirst and pulls yor arrows out of the 3d gritter .nice 11/32 tapered to 5/16 .he pulls them out by the taper bingo the arrow is crooked enough to notfly right.paralells stay strait easier or longer and fly just as well .

[arrow flynn]

add to above imho

[Orion]

Are they perfectly straight before you taper them?  Shouldn't be any harder to straighten after tapering than before.  Are you tapering hardwoods or softwoods like cedar, spruce and fir?  Hardwoods tend to move around a bit regardless.

[deaddoc4444]

Several things to check    Make sure the shafts are straight  PRIOR to tapering them .  I use the same basic method and I Have NO problem with warped or crooked ends  after tapering and I taper  16 inches  not the usual  10 or 12.
   Make sure of your spine if you need "EXAMPLE" 60/65  spine  and you start with that spine  YOU  will reduce the spine by tapering because your taking wood away.  Making them weaker .
   I made some  tapered  arrows for my son lately and started  with 70/75 shafts   after taper  re spined at   66/68   THEY flew great and   have   hundreds of shots out of  his bows  on them with out any Warping.    
   Tapers ALWAYS fly better  IMHO.

[deaddoc4444]

SORRY should have mentioned these shafts are POC  that I used for my son.   I also make tapered shafts out of Poplar.   Same thing applies   taper reduces spine.  Poplar seems to reduce even more   than POC . SO you need to check spine after tapering .