One problem is that weight varies a lot from shaft to shaft. Most good wood arrows are sorted but there can be a big difference between sorted groups. Spine depends a lot of initial velocity, which depends on weight. Another factor is that spine depends on orientation. Some wood shafts could have significantly different spines depending the nock orientation. Wood is more art than science. I am interested in what Bender says. He is a good wood guy.

 

Hello.

The arrows you've built her are about 10 grains per pound of the bow's weight at her draw (36# on the fingers at 23" ... I am assuming she is shooting a bow marked heavier than 36# and that you are stating the calculated or measured weight on her fingers at her reduced draw length from the designated marking on the bow at 28"), which is fine if she is just getting her feet wet with wood arrows. Wood shafts are, in general, naturally heavier then carbon or aluminum, especially at her poundage ... so it is usually harder to get them as light as one may desire, rather than heavier. Heavier shoots slower, and for target shooting you may wish to keep the weight as it is now so her arrows obtain their maximum zip (this assumes a 70 to 125 grain point). Hunting can become a different story for weight needs depending upon what equipment the archer prefers in this situation.

Attempting to manipulate the natural weight of the shaft with point weight is done via formal tuning methods in order to mate the arrow to the bow for the best flight. I don't know whether or not the shooter is into the tuning processes yet, so I'll leave that out of this initial commentary. So long as the arrows are shooting nicely for her, there's no need to add more weight simply for the sake of weight, for she is already shooting within an acceptable weight norm.

By the way, most wood charts assume a 125 grain point on a 28" arrow in calculating the spine, and after that it is up to the archer to make the necessary spine adjustments by calculating shaft length and point weight for any variations away from that chart's baseline .... usually in 5 pound increments either up or down in spine. This explains why you haven't found the detailed wood chart that you were looking for.

Hope this helps, and holler back with more specifics should you want more information tailored to her situation.

 

Just to clarify, although it is common to see wood arrows classed into "weight" groups, that is actually a reference to the what bow draw weight the arrow is appropriate for. This is important to tuning in order to have an arrow that flies well, and can be accurate. It is entirely different than the actual mass of the arrow itself.

Go here:

http://www.acsbows.com/bowtuning.html

Click on "Download Printable Version."

You will find both a table like you mentioned that relates draw weight to an arrow's "weight" (not mass) AND a good initial guide to the tuning process. You can decide for yourself if tuning is something that you want to start to get into. Obviously everybody wants arrow that fly right. BUT until one has some decent form and consistency, tuning can quickly become horribly frustrating. But read the document, and with a little thought, and some research before buying new arrows, you should be able to get something that is at least better than a wild random guess.

 

10 gr/lb is reasonable. I certainly wouldn’t be looking to go any higher…but that doesn’t mean there couldn't be a heavier shaft that's more suitable to the bow and the shooter. I’ve been following my practice with a handful of heavier arrows and I much prefer them for their stability over long distances, even though it takes them longer to arrive at the target (…hard to commit to “formula” when trade-offs accompany most every option).

Beyond that I would consult with more than one of the people producing wooden arrows. Most specifically I want to know what’s available in 5/16 shafts. I just wouldn’t be happy with a larger diameter at that draw weight and length…most everything else (within reason) I would consider secondary.

As far as going with lighter arrows someone should remind you that some bow’s warrantees become void if you go below a specified gr/lb…which would also be a worthwhile guideline. Rick.

 

Two things about wood that I have learned over time is that weight is not as critical as is shaft diameter on traditional no shelf or narrow shelf, and spine.

 

I have about a 25 inch draw length and a longbow that is rated 35# at my draw length. My most recent set of wood arrows I cut to about 26". They are 5/16" diameter Port Orford cedar, spined at 25-30. Because I cut them much shorter, they will be stiffer. I use 100 grain points.