I am using a tru-taper tool. This sure is frustrating hearing that noone has ever seen a problem like this.

On the subject of the grain, let me elaborate more to how I align. Grain lines run East to west. String in the Knock throat run North to south.

Split down the arrow shaft, like the string is a band saw, north to south.

you mentioned your nocks are tight.are they cracking after a few shots and then they let go?? being glued to the nock end maybe they are split and when the string pushes the platic apart the wood follows?

I just got off the phone with Randy at 3R. he was very helpful and experienced (30 yrs) with woodies.

He is mystified as well. He is going to consult with some of the other guys there at 3R, and call me back.

Thanks,
Matt

Some times when using nocks that may be different than you are used to, finger placement pushes the nock forward so that it is not tight to the string. This might create forces that could crack the nock and subsequently the arrow.  Truely a guess on my part.

You said you put your nocks on and then spray on your finish. Could the Poly curing process be damaging the plastic???

Eric

How tight do the nocks fit on the string??? I have some T-nock, I dont use them, and the throat is very tight until it gets to the string pocket. Could be weakening every shot until they fail.

Eric

I've noticed that the material used to make the classic index nock that I've used for years has changed. Before, the material was softer and more flexable where as now the nocks are more brittle. They break away easier when hit by another arrow with less damage to the wood taper. That's good and bad. Less damage to the wood taper is good, having to replace a lot of nocks isn't.

I'm sure it's something very simple with your nock but if you want to prevent futher shaft splitting you need to apply a thread wrap right below your arrow nock. After hitting and having to replace hundreds upon hundreds of plastic nocks without ever splitting the first shaft I feel confident in suggesting this. Matter of fact, I won't make any arrow up without doing this. Be it hardwood or soft.

I suspect your nock is splitting from to tight a nock/string fit and the nock material is somewhat brittle. Lot of other factors can place unneeded stress on your arrow nock aswell. Such as, release, improper arrow spine, nock height, double string nocks and the like.

ART B

Like Atick N String I have made thousands of wood arrows with plastic nocks and never this problem.  If they are truly a good POC shaft that should not be it.  I used to think about cross grain (30+ years ago) but am convinced that since the strain of the shock on the shaft is supported by the plastic nock around the whole area of the sahft, cross grain is not an issue.  If you were doing self nocks, then it definitely is, as well as nock width so the string size does not spread the nock.

I have used DUCO for years - Everfast and 24SRTX before that (how many of you guys remember that stuff)  There is no need to go the expense of Fletch Tite Platinum on wood arrows when DUCO works great and you can get it for $.97 at WAL Mart

I would like to see pictures of the split arrows.  What diameter and type of string are you using?  What is your Bow weight.  Are you sure about the arrow spine?