i agree with Pat,
the 3/8" dowel shaft from home depot is way to thick or wide of a diameter for a short arrow of 24"... and if your draw is a 24" draw then you should cut arrow length up to a min of 25 1/2" but would probably do better with a 26" arrow... i have used the 5/16" oak dowels for arrows with great success and have had them turn out a good accurate set... in fact all the boys form the youth group are using just that... and the 5/16" oak dowel from lowes make great arrows... of coarse they are bieng shot from 35# f/g long bows but are actually a short bow of about 56 -58 inch in lenght...
as for feathers... there are alot of places you can get some feathers... you can hunt for them locally around pounds and anywhere you see birds flock to... but if you want to buy some feathers any good sports store will have some... if you have a cabela's or bass proshop near you they carry some pre-cut fletchings... or a academy sports store or a sports athority should carry some too... if your looking for some natural type feathers you can find them at hobby stores or anywhere they sell fly fishing rig supplies... kinda expensive to go that rout but not bad way to try and get some locally for just a few arrows...
im sure if you have no luck im sure somebody on here would be willing to send you some... jsut enough to make a few arrows shouldnt be a problem to get somebody here to help out with that to a new arrow builder...
but if i were you id definantly try useing the 5/16" dowel instead of the 3/8" are you cuting self nocks or are you using plastic nocks.. what type of tips you using???
i have used and tought the boys how to make fletchings out of duct tape to for an improvised survival or field arrow... pretty cool to be able to make something out of hardly nothing huh?
but if i were you, id try some feathers out... i guaranty you will like them better...lol..
if you cant find some feathers to use or buy some let us know im sure somebody might offer to send you a few...
but waht ever you do... make sure you keep building em and shooting them... and have fun!!!!