Arrow Spine or Bow Problems??

[SEMO_HUNTER]

Since the limb repair on my Osage Longbow, the first thing I noticed was the poundage increased which I expected to happen. The next thing I had to do was re-tiller the limbs because the Flax won't allow the limbs to flex as much in those areas of the limbs anymore. No biggie, a few minutes with the belt sander and even tiller again, and back to original poundage of 45lb. at 26" which is what my target weight and draw length was.

Here's my problem. My arrows shoot predominantly left, which would indicate spine issues and they are also not coming off the bow cleanly. I can see some whip as they come off the bow.
I've already spined my shafts down to .640 which is spined for about a 40lb. bow, and I would think this should be light enough, but are longbows different than recurves in the respect to what spine they prefer as far as heavy spine versus lighter spine? Because evidently my chart isn't helping me hit it right?
I went by the chart and my home made spine tester for my recurve and I have 4 arrows spined exactly for the weight of the recurve and they shoot awesome, but for some reason those same rules aren't working for my longbow.

So, it's got me wondering if it's the bow, if it's fletching contact on the riser, or if I need to keep spining my shafts down until they come around??

Any help or advice would be greatly appreciated.

Thanks,
SEMO

[Old York]

If you use Stu's Dynamic Spine Calculator, load in all the data, then make changes in the "Bow Inputs - Strike Plate Position" field, you can virtually see the effect the degree of centre-cut has on dynamic spine.

Other than that, it sounds like you're well at hand with what's going on and needs to be done, try weaker spined shafts and lipstick....now that's lipstick on the fletching edges to check for clearance at the arrow pass. Sometimes the best I've gotten is "decent flight" but still with some fletch contact. Cock feather in helps too.

[SEMO_HUNTER]

Originally posted by Old York:
If you use Stu's Dynamic Spine Calculator, load in all the data, then make changes in the "Bow Inputs - Strike Plate Position" field, you can virtually see the effect the degree of centre-cut has on dynamic spine.

Other than that, it sounds like you're well at hand with what's going on and needs to be done, try weaker spined shafts and lipstick....now that's lipstick on the fletching edges to check for clearance at the arrow pass. Sometimes the best I've gotten is "decent flight" but still with some fletch contact. Cock feather in helps too.

Cock feather in??
That seems to go against all rules of arrow contact? But at this point I'll try just about anything. As far as contact with my riser, that's always going to be an issue because I shoot off the riser of the bow and I have a small cut out to hold the arrow shaft, with a piece of beaver stuck to it, with a piece of camo sticky pad for a side plate, mostly just to deaden the arrow as it's laying against the riser.

I do think I'm making progress though? I got my tiller nearly perfect now, and spined my arrow down to .680 and that seems to be helping, but still not perfect. It may be that perfect will never happen with my longbow?
It would be nice to achieve as perfect as possible before I stick some broadheads on it though, because I know what kind of nightmare that can be to tune broadheads with erratic arrow flight....it only compounds the problems when a broadhead is involved.

Thanks for the help, I'll check back in periodically and update my progress. I'll be working on this all day until I get something figured out.

[Chub]

i shoot cock feather in i seem to have cleaner arrow flight .also use stu millers site and paper tune then stsrt shootin fpts and bhs and go from there

[dcmeckel]

I also was having trouble tuning my newly made rig when I decided that the only thing that I HAD NOT tried was a different string.
Well I twisted up a 12 strand,got rid of the 16 strand,and, believe it or not,that took care of my erratic arrow flight.
Hope this helps more than hinders.

[SEMO_HUNTER]

I tried that cock feather in just to see what it would do.........not good! That arrow jumped off the side of the bow so bad that I sunk my field point into the wall in the back of my garage! I completely missed my block target. I got it out, but there's a nice little reminder in the wall to never do that again!

DC- I sure hope I don't have to go that route? I order 2 brand new Flemish twist strings and they look awesome on my longbow, but that's all I have for it. I may try adding or taking away some twist and see what that does?
I am going to work on the riser area a bit and thin the handle down some more, I think I made my shelf too big and that's causing me problems too. I reall find it hard to believe that the spine is that much of a problem because the longbow is 45# and my recurve is 48#....so they should both be able to shoot the same arrow...correct? Well, the recurve shoots great.......longbow not so great with the same arrows.

Thanks for all the suggestions guys, I appreciate it.

[Whump]

Whump Sez; well- your degree of center cut or lack of is probably what is stumping you on the long bow "A recurve will digest a lot stiffer spine being cut closer to center". If you are shooting wood you can always sand one shaft down a little weaker and play with that one arrow until you come across the magic deflection number.  I just finished an arrow tuning project like that on a board bow. You can also go real heavy or light on point weight until that solves the problem--but judging from the hole in the garage I would say you turned a wood shaft to the stiff side when you turned it cock feather in and that caused it to fly excessively wild rather than the fletching having an affect on it.If your arrows are flying left for a right handed shooter then you are on the stiff side on spine.  Hunt safe.

[SEMO_HUNTER]

Well, you are right Whump. All of the rules of thumb point toward too stiff of a spine and I need to work one of these shafts down some more. I believe that I was trying to solve 2 problems at once and it was boggling my mind a bit. I think I have one of those problems solved now.

I gave my riser handle area a buzz cut. I left it too thick all the way around, trying to make it resemble a recurve riser and that wasn't working at all. I thinned it down quite a bit to look more like a traditional longbow riser/handle, then I made the cut out a touch deeper into the center of the bow. I got rid of my hair rest and taped a flipper rest just above my hand with some fiberglass tape and then tested again with my woodies. Just as I suspected, the arrows drifted over closer to the center of the target and the whipping was almost gone.
They still shoot a little left, but I believe that is due to the spine and I can fix that easy enough. It's showing a lot more promise now than it was about 2 hours ago. I was almost to the point of building me a fire in the wood stove in the garage and using Osage longbow as kindling, but I didn't. I just walked away and gave it a rest, then came back a while later with a fresh attitude and I think it paid off.

I'll do some fine tuning again tomorrow and see what things look like by the end of the day. I'm sure it will be a better outlook than today was.
It's been a real learning experience on this first Osage longbow build and I'm thankful for it because I will be a plethora of mistakes ahead of the curve when I build my perfect longbow this winter. The next one is going to be sweet.

Thanks for all the help guys!

[Whump]

WHump Sez; I should have added that it took an arrow deflection of.722 to shoot to center on the red oak board bow and it pulls 48 @ 28" 125gn point. I have talked to several people that shoot fast flight strings on self bows. They leave the tips a little thicker to solve tip pop off. This allows for quite a difference in arrow speed so you don't run into what we both did, having to shoot a noodle to get the spine correct. As you well know the speed of the bow you build has a huge bearing on spine, so a screamer will shoot a stiffer spine than a bow that has snails honking to pass the arrow . Since your bow is osage you might try to narrow you limbs some at the tip.  Start about 4" below the tip narrowing toward the string grooves and that will increase your limb speed, improve cast, help reduce hand shock, and allow for a slightly stiffer spine. The tougher osage can stand a lot smaller tip than my red oak bow. Your on the right track--good luck.  Hunt safe.

[SEMO_HUNTER]

I'm right at .640 right now and was prepared to go down to .700 if need be, and after reading what you just wrote...it sounds like I might need to.
I'm working on a few cosmetic aspects of the Osage bow right at the moment, but I believe that I'm almost there. The riser looks completely different than what it did, but in a good way I think? At least I'm making progress in the right direction and there's light at the end of the dark Osage longbow tunnel.

Thanks for the good advice. I'll post some results here this evening.

[SEMO_HUNTER]

Thanks to the moderators for moving this, I wasn't sure where it belonged when I started it?

As it turned out.....it was several problems all rolled into one, so if there was a category for it, it would fall under "Mutt" as in many breeds of problems all rolled into one.   :D