Ceder shafts. Weight question too.

[ionicmuffin]

So today i found some awesome ceder with somewhere like 20-30 rings per inch, so i cut a bunch of them to the right sizes and will be running them through a dowel turner. (out of 12$ i got 21 usable shafts, meaning 57 cents per shaft.) I just weighed the dry one and its reading 1.25 ounces. so i went ahead and calculated the actual volume of the shaft (6.75in cb) and then i calculated the volume of the shaft i will be turning.(2.94 in cb) so then i divided the 2.94in by 6.75in and came up with .44 so that means that the shaft would weigh 44% of the weight i took with the shaft. So once i multiplied .44 by 1.25oz i got .55oz. In conclusion i came to about 240 grains per arrow+ the feather/glue/tip weight. The one question i have about it is that if i have 240 grained arrows and add a tip with 50-125 grains and fire it from a 20 lb bow will it loose performance over a 200 grain arrow? I know the 650 grain arrow ive been shooting from it was sluggish. Let me know what you think. ill post pics of the process.

[DarkSoul]

I'm not quite sure what your question is. The lighter the arrow, the higher the velocity. It's as simple as that - not much physics involved. "Performance" of a bow is a more complex term. What do you define as performance? Efficiency in energy transfer from the bow to the arrow? Arrow speed?
The general consensus is that a bow requires an arrow of about 10 grains per pound drawweight. So about 200 grains for a 20 pound bow. If you shoot a 650 grain arrow from this bow, well, surprise! The speed will drop.

[Tom Leemans]

O.K. I don't want to criticize, but what are we trying to get at here? I'm with DarkSoul. What is the definition of performance? Speed? Kinetic energy? and what are the final dimensions of the arrow shaft anyway? I'm a real practical guy who likes to see what happens, but within reason. Calculations don't excite me much. I'm not sure what you're going for here, but I'm not the type to push certain envelopes. You go light enough, you'll end up with an exploding arrow. One last question. Why a 20# bow?

[ionicmuffin]

the arrows i made were 11/32" tipped with 125 grain tips and they ran about 240 grains before tipping. I made a 20 lb bow for my sister, its exactly what she needed. she can pull it just fine and shoots well. The arrows are 25" long. I was going for arrow speed, fps.

[Buckeye Guy]

Try taking them down to about 5/16 ths !
Have fun
Guy

[billn]

If you really want to reduce weight, you can always taper the shafts.  Just make sure, in the quest for velocity, that you do not reduce the spine too much.  I use tapering to match arrow weights on my target arrows.

I would use smaller diameter shafts. 9/32" is plenty large for bows with a much higher draw weight than yours. I have seen students in a youth archer program using 1/4" shafts with very light weight target piles. The extra velocity is nice for the longer ranges.

It sounds like you are at 350+ grains. If the spine is proper for the bow, then they should shoot fine, just quite a bit slower than necessary. The arrows I shoot with my 35# longbow weigh about that much.

Bill