arrow spine
When building arrows for use with a thumb ring should they be spined to the given weight of the bow or higher .. I have heard some say that for shooting with a thumb ring that you should increase your spine weight...
I think it should be significantly more than with 3 fingers too, probably due to added cleanliness of the release. If not, then you could end up with the tail of the arrow hitting the bow. Though technique is important in avoiding that too.
Any thoughts as to how much to increase the arrow spine over the stated bow draw weight ?
I have a Saluki Crimean Tatar hybrid that is 64 pounds @28 inches and thinking I will be drawing 30 or perchance 31 inches with a thumb ring , not sure how much the actual draw weight will be at two or three inches over the 28 inches... Need to get this figured out so I can build some arrows for it...
I fail to see how draw method would influence the desired spine weight. The effect of spine on arrow flight takes place only AFTER release, not during it.
Because the thumb release is cleaner so the arrow doesn't flex as much on release. To compensate for that the bow is twisted (Khatra) on release so the arrow will clear it. With the three finger release the arrow needs to flex to get around the bow, hence the concern about spine weight. With good technique spine weight becomes a minor concern with a thumb release.KenH wrote:
I fail to see how draw method would influence the desired spine weight. The effect of spine on arrow flight takes place only AFTER release, not during it.
I don't know if you have looked at the Thread on Mongolian Release on the "Wrong" Side ( http://www.atarn.net/phpBB2/viewtopic.php?t=2721 ) in the Technique section. Rydragon posted a nice video comparing the atypical Mongolian release with standard release with and with out Khatra. It does a good job of showing what I am talking about.
I use 60-65# shafts (because they were the heaviest I could get on sale at 3 Rivers) in my 50lb @ 31in Korean Bow and they work well. I would get stiff arrows and worry more about form and getting a proper khatra release then the spine.Alan Flashing wrote:
Any thoughts as to how much to increase the arrow spine over the stated bow draw weight ?
I would just get bamboo arrows or tapered wood arrows that are slightly longer than your draw, maybe 1 or 2 inches. For every inch over 28" you draw, people say to add 5# to the spine... which would be 84# with a 32" draw. I think you could get away with something of a bigger range using non-parallel arrows.
There are several issues with the spine effect when using a thumb release.
As pointed out above, a finger release in general puts more lateral deflection on the nock than a thumb release, but all thumb releases are not equal and some may induce a lateral pressure of their own because of pressure on the nock just before or during release. This comes from the proximal section of the index finger when there is too much turning of the wrist anticlockwise (for a right handed archer). This pressure is necessary in Japanese archery to keep the string in the shallow groove of the yugake's thumb, but almost always causes problems for users of thumb tabs or rings.
The arrow will buckle even if a mechanical release that creates no deflection for the string at release. However, the degree is usually less with a thumb release than a finger release which means you should be able to use a lighter spined arrow with a thumb release than with a finger release. this is what we do in flight archery because we need to reduce arrow mass.
Spine matching arrows was developed in the West in the nineteenth century for target archery using longbows and a three finger release. The purpose was to make use of the existing deflection to clear the bow and to avoid having a dramatic mismatch of the oscillation of the arrow causing part of it to hit the bow handle with force. Prior to that time, the main consideration was that the arrow be stiff enough not to break under the force of the string. This is still true of most Asian traditions. For example the Koreans match the weight of the arrow to the bow. There is a detailed table of the same thing in Arab Archery where bow weights, arrow masses and distances are laid out for competitions. The reason this works is the density of a given wood or bamboo species is on average proportional to its stiffness and strength. There are exceptions because natural materials vary from piece to piece.
My recommendation is to test several arrows to find out which spine works best for you. If you have a particularly good release, you may find a lighter spine works for you. However, the stiffness of the shaft has to be higher if you use heavier heads. Flight arrows have heads that weigh a few grains and the shafts can be less stiff than target arrows or hunting arrows. Starting off slightly heavier than recommended for a finger release and working down until you see the arrows flying badly is a simple approach. Or you can stop testing when you find an arrow that flies straight enough for your purposes. Matching the weight of your practice heads to your hunting heads saves worrying about different spined shafts for each.
The comment that the thumb release increases the range of spines you can shoot matches my experience. You only need adjust your aim to correct for the different deflection. It is not inconsistent as it sometimes is with finger shooting.
After a post on another forum about arrow behaviour with a thumb release I tested the effect on arrow flight of increasing the pressure on the nock before release. At 30 metres I could see that increased pressure increased fishtailing and noise from the arrow striking the bow. With no pressure on the nock, the arrow departed perfectly straight and was quiet.
As pointed out above, a finger release in general puts more lateral deflection on the nock than a thumb release, but all thumb releases are not equal and some may induce a lateral pressure of their own because of pressure on the nock just before or during release. This comes from the proximal section of the index finger when there is too much turning of the wrist anticlockwise (for a right handed archer). This pressure is necessary in Japanese archery to keep the string in the shallow groove of the yugake's thumb, but almost always causes problems for users of thumb tabs or rings.
The arrow will buckle even if a mechanical release that creates no deflection for the string at release. However, the degree is usually less with a thumb release than a finger release which means you should be able to use a lighter spined arrow with a thumb release than with a finger release. this is what we do in flight archery because we need to reduce arrow mass.
Spine matching arrows was developed in the West in the nineteenth century for target archery using longbows and a three finger release. The purpose was to make use of the existing deflection to clear the bow and to avoid having a dramatic mismatch of the oscillation of the arrow causing part of it to hit the bow handle with force. Prior to that time, the main consideration was that the arrow be stiff enough not to break under the force of the string. This is still true of most Asian traditions. For example the Koreans match the weight of the arrow to the bow. There is a detailed table of the same thing in Arab Archery where bow weights, arrow masses and distances are laid out for competitions. The reason this works is the density of a given wood or bamboo species is on average proportional to its stiffness and strength. There are exceptions because natural materials vary from piece to piece.
My recommendation is to test several arrows to find out which spine works best for you. If you have a particularly good release, you may find a lighter spine works for you. However, the stiffness of the shaft has to be higher if you use heavier heads. Flight arrows have heads that weigh a few grains and the shafts can be less stiff than target arrows or hunting arrows. Starting off slightly heavier than recommended for a finger release and working down until you see the arrows flying badly is a simple approach. Or you can stop testing when you find an arrow that flies straight enough for your purposes. Matching the weight of your practice heads to your hunting heads saves worrying about different spined shafts for each.
The comment that the thumb release increases the range of spines you can shoot matches my experience. You only need adjust your aim to correct for the different deflection. It is not inconsistent as it sometimes is with finger shooting.
After a post on another forum about arrow behaviour with a thumb release I tested the effect on arrow flight of increasing the pressure on the nock before release. At 30 metres I could see that increased pressure increased fishtailing and noise from the arrow striking the bow. With no pressure on the nock, the arrow departed perfectly straight and was quiet.
Lukas just wrote me yesterday and said that as far as arrow spine weight is concerned that I should add 5 # of spine weight per inch of draw beyond the stated weight @ 28 inches...
Great thread because I've been struggling with arrows banging on my bow upon release. Tested with different point weights and paid more attention to my release helped fix the issue a bit, but still experiencing some fishtailing and I could not figure out whether my spine is too soft or too stiff that's causing it.Bede wrote: ↑Wed Mar 23, 2016 4:11 am
After a post on another forum about arrow behaviour with a thumb release I tested the effect on arrow flight of increasing the pressure on the nock before release. At 30 metres I could see that increased pressure increased fishtailing and noise from the arrow striking the bow. With no pressure on the nock, the arrow departed perfectly straight and was quiet.
When you say 'pressure on the nock' what does that mean? This may be the holy grail. :)
I suspect he means "squeezing" pressure -- sideways pressure -- on the nock.
If this is meant, I suggest to avoid pressure of the index-finger (sideways) against the arrow completely. Avoiding it helped me a lot, and I understand it as helpful while you are in motion (riding, running, ...) but it doesn't help (me) in a good shot at all. Unsurprisingly all manuals on thumbring-archery I've read seem to call any pressure against the nock upon release a mistake leading to fishtailing.
(For example in: "Arab Archery" by Nabih Amin Faris and Robert Potter Elmer, Chapter 28, first mention.)
And on spine: The huge diversity of bows from manchu to turkish and back again doesn't help to give any general suggestion. I'd suggest a bareshaft test. It shows you if your arrows are too stiff or too weak. I find it so much more helpful then a "just add 5#" suggestion (because this will only be true for a tiny fraction of users). This way you find out, what works for you.
(For example in: "Arab Archery" by Nabih Amin Faris and Robert Potter Elmer, Chapter 28, first mention.)
And on spine: The huge diversity of bows from manchu to turkish and back again doesn't help to give any general suggestion. I'd suggest a bareshaft test. It shows you if your arrows are too stiff or too weak. I find it so much more helpful then a "just add 5#" suggestion (because this will only be true for a tiny fraction of users). This way you find out, what works for you.
Thx guys, this is great insight.
I came from several years in shooting recurves and have developed a habit of canting my bows. With thumbdraw it’s no different and I need some nock pressure to keep the arrow against the bow during the cant. I could see now how this lateral pressure could cause the arrow to fishtail upon release. Another problem compounding to this is my anchor point when I draw and place feathers against my cheek and I need again that nock pressure to keep my cheek from inadvertently pushing the arrow out of my bow. Any thoughts on this?
I came from several years in shooting recurves and have developed a habit of canting my bows. With thumbdraw it’s no different and I need some nock pressure to keep the arrow against the bow during the cant. I could see now how this lateral pressure could cause the arrow to fishtail upon release. Another problem compounding to this is my anchor point when I draw and place feathers against my cheek and I need again that nock pressure to keep my cheek from inadvertently pushing the arrow out of my bow. Any thoughts on this?
There are shots where I have to cant the bow, too. These are the situations, where the pressure - obviously - can't be avoided. For these shots I use as little pressure as possible. When time is no issue you can play with this at full draw. You reduce the pressure until the arrow starts to move on your thumb and away from your bow until there is a gap of 1mm between arrow and bow. Then you increase the pressure carefully again to close the gap again. Once you feel the needed minimal pressure, you loose the arrow.
Hope this helps!
Hope this helps!
Got it. Thx for the tips!