Primitive Archer
Main Discussion Area => Bows => Topic started by: DC on March 08, 2020, 03:06:58 pm
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I just ruined the bow that was going to break 200(I wish :D) by using a longer than usual long string(I had a thought, duh) and couldn't think why it had failed. It ended up light. I thought some research was in order so I was searching some old threads on tillering and found this old quote from Badger back in Dec/2013
The important thing to remember when working with a long string is that the poundage reading you are getting has more to do with how far your string is hanging down than it does the deflection of the limbs.
I had been thinking that the only difference between the long and shorter long string was that the shorter string pulls in as well as down. After I read the quote it dawned on me, "string angle changes the mechanical advantage" so by pulling straight(ish) down your scale is going to read heavier(think I got that right) so you take off a lot of wood. Then when you brace it, it's light.
Did I get it??
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thanks for that finding DC - I'm always pulling my bows 60# on the long string - then I often wonder how fast I'm on lower drawweight after bracing it first. I will consider that from now on. thanks!
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I don't know if this will help or not, but I was pointed to this thread about measuring draw weight using a slack string and it seems to relate to your quote. There are some interesting test results in the last post.
http://www.primitivearcher.com/smf/index.php/topic,65722.0.html
Mark
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The bow I ruined was a Boo backed Yew. I had it on a long string that drooped about 22". I was pulling it to 40#, no more, and I tillered until the tips went to my brace height line. Equivalent to about 7" BH. I braced it and put it on the tree. It went right to 37#@28". The tiller was crap and I had no room to fix it. I was some surprised I tell ya.
I just did a test. I strung a bow and pulled it until the tips reached the 10" mark. It was 23#. Then I unbraced it and put on the long string and pulled until the tips reached the 10" mark again. This time it was 37#. Wow wasn't expecting that much. Good day I learned something :D :D. Something that I should have learned five years ago :-[ :-[ :-[
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I don't know if this will help or not, but I was pointed to this thread about measuring draw weight using a slack string and it seems to relate to your quote. There are some interesting test results in the last post.
http://www.primitivearcher.com/smf/index.php/topic,65722.0.html
Mark
I remember that post. I'll re read it. Right now it's nap time.
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Not only does the long string deceive in draw weight, but in limb action too. A shorter string makes the outer limbs bend more due to the inward tension you mentioned. So using a long string that's waaaayyy too long, and for too long in the process can lead to light weight, whip-ended bows. If we're aware of it and learn to deal with it, it's a useful tool that won't lead us astray.
I use the long string, but keep it shorter. It still deceives a little, but I know that, so I don't bother to put a scale on it or look to get the outer limbs bending much until it's braced. Oh, and don't use the long string any further than needed to get the thing braced.
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My long string is about 72” long . So on a 67-69” The bow string just barely hangs below the bow. I have found that pulling the bow close to brace yields close to full draw weight. So if it’s at sixty pounds I have some room for corrections. I always still floor tiller so I’m usually pretty close at long string time. Arvin
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I am really glad I read this.
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I did a few tests and the longer the droop the more the weight changes. Like DWS said, knowing this is important and is just one more tool in the quiver. The reason I was even trying the very long string is that I'm working with very high reflex bows and I've found that if the string is still in contact with the bow, the bow doesn't bend much if at all. This makes getting the outers to move very tough and as the bow does bend a little more of the outer is exposed and should bend. That meant string on, string off tillering. The long string was an attempt to be able to get at the outers and get them moving. I was aware of the tips bending more but I wasn't aware of how much the weight would change. My fault.
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For me anyway I’ve already got a comparable pull to reading whether the bow is braced or if I’m using a long string that’s just off the belly. If I’m getting 60# at a 20” pull with the long string t he I will see about 60# at 20” when braced. The difference will be t he shape of the tiller and how far the limb tips move to hit the draw to point. As has been stated the outers of the limbs will be under more stress and bending more. So when your looking to be able to brace you need to keep an eye on where your hooking point is when your at weight in addition to where your tips are bending to. That’s also why I like to go to an intermediate low brace stage of about 2-3”. With that I can get a little more tip movement and see closer to it’s true look before I hit a full brace.
Kyle
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Yes, if you just have a bit of droop, say 0-5 inches it's very close. In order to get the string off the tips I had 22" of droop. Like I said, I was trying something. It didn't work but now I think I have the brain tools to make it work. :D
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Something I have been doing for years and I never come in light. I try to have the long string with less than 6" slack. I ignore tip movement entirely when measuring the weight. I read the weight just as if the bow were braced and I find it is not much different. As a rule I will brace a 50# bow when it is reading 50#@24" on the long string. That gives me about 10# to remove.
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Yes :)
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Thanks for bringing this up again. I've been chewing on the other methods people use, especially Badger's. It intrigued me because it was contrary to some of my preconceived notions about long strings. Even though I don't use the long string any more for my own bowmaking I want to play around with this method as a teaching tool. It's a bit more objective and "by the numbers" than the way that I typically use.
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long string threads pop up just about every winter, and the new guys are probally reading with interest along with the more experienced.
When I was learning the technique, I was often confused by the draw lengths different folks mentioned, as different lengths of droop read different on the tiller tree for the same bend. So just to clarify for the sake of the inexperienced, I need to ask Badger a Q.
Something I have been doing for years and I never come in light. I try to have the long string with less than 6" slack. I ignore tip movement entirely when measuring the weight. I read the weight just as if the bow were braced and I find it is not much different. As a rule I will brace a 50# bow when it is reading 50#@24" on the long string. That gives me about 10# to remove.
brace when it is reading 24" pull on the tiller tree while using a longstring with 6" droop?
also, Steve, do you ever shorten the longstring as you go, like some seem to reccomend? if so for what kinds of limb configurations?
thanks
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The length of the sting doesn't affect the weight much. I usually try to be between about 2" and 6" and it will weigh very close to the same.
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Sure, I understand that the weights will remain similar. I was just trying to confirm that your recommendation to brace when you tiller out to 24" on the tiller tree is based on using a longstring with a 6" droop.
thanks
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I just tillered one. I went with the long string drooping about 6". Tillered it to 40@24". Braced it to about 6", put it back on the tree and it pulled 40#@24". :D :D
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The bow I ruined was a Boo backed Yew. I had it on a long string that drooped about 22". I was pulling it to 40#, no more, and I tillered until the tips went to my brace height line. Equivalent to about 7" BH. I braced it and put it on the tree. It went right to 37#@28". The tiller was crap and I had no room to fix it. I was some surprised I tell ya.
I just did a test. I strung a bow and pulled it until the tips reached the 10" mark. It was 23#. Then I unbraced it and put on the long string and pulled until the tips reached the 10" mark again. This time it was 37#. Wow wasn't expecting that much. Good day I learned something :D :D. Something that I should have learned five years ago :-[ :-[ :-[
What does the weight read if you pull it to 6 inches of string movement? That would be 28in from the back of the bow including the 22in droop?
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I've changed the length on the string now and can't go back, sorry.
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I just tillered one. I went with the long string drooping about 6". Tillered it to 40@24". Braced it to about 6", put it back on the tree and it pulled 40#@24". :D :D
I too use long string. A "tight" long string. Very little or no "droop".
Long string tiller to about 5" less than my draw length. Then brace.
Get same results as DC reported. Draw weight will be virtually same as long string was at same draw length.
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Long string is the great deceiver lol floor tiller to low brace is the only way I do it. Haven’t come under weight since.
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Have concluded tillering a bow is a very personal individualistic(?) endeavor.
What works for one doesn't work so much for another.
It was fun, and sometimes bit frustrating, trying various approaches.
But eventually ya settle into "your" process.
Appreciated learning of the different approaches and their pros/cons.
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I've changed the length on the string now and can't go back, sorry.
10-4 just curious if it was closer to the 23# or 37#.
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Long string is the great deceiver lol floor tiller to low brace is the only way I do it. Haven’t come under weight since.
How can it deceive you? An inanimate object can't remove wood ;) You just aren't using it right :)
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Nah my dude. The long sting hides deeper imperfections in the actual tiller Of the bow. If your floor tiller is good. It might be heavier but floor tiller to low brace won’t cause set or hide imperfections.
I have yet
To break a bow or come in underweight, so I must be doing something right. 12 years of this sorta thing under my belt.
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DC, simple method and it is the most accurate method I have found to determine exactly where you are in weight. I have guys all the time tell me that they tried it and it doesn't work. I don't know what to tell them because I have been doing it for years now and it works every time.
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I'm thinking that the whole thing depends on the length of the long string. I've seen pictures people have posted of their bows on the long string and some are really long. If you get into the 15 or more inches of droop the test I've done show a significant difference in weights. Six inches or less droop and the weights are very close, like you've been saying all along. Just to clarify, when I say droop I'm talking about a little bit of tension on the string so the string is straight on either side not curved. This is a simple thing to show yourself if you have a scale and a bow and a long string. It's something that everyone should do.
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Here is how I do it: I have never been able to really see the bend well when floor tillering, so I get the stave just barely moving at floor tiller and then move to a "long" string that is the same length as the stave. At this point I pull either until I see a flaw/unbalance or until I hit my draw weight. At this point that will be well under 8 inches. As the draw length increases, I shorten the string, bracing at 1", then maybe 3" and at 5" Then I go to full brace. Once I hit full brace, I am usually pulling about 22-25" on at my target draw weight, and most of the bend has been evened out. the last few inches are hopefully careful weight reduction with only very minor corrections. It has been a pretty good method for hitting my target weight.
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Here is how I do it: I have never been able to really see the bend well when floor tillering, so I get the stave just barely moving at floor tiller and then move to a "long" string that is the same length as the stave. At this point I pull either until I see a flaw/unbalance or until I hit my draw weight. At this point that will be well under 8 inches. As the draw length increases, I shorten the string, bracing at 1", then maybe 3" and at 5" Then I go to full brace. Once I hit full brace, I am usually pulling about 22-25" on at my target draw weight, and most of the bend has been evened out. the last few inches are hopefully careful weight reduction with only very minor corrections. It has been a pretty good method for hitting my target weight.
That's my normal method too. Works great. I've been searching around for a method that will get me better results with high reflex RD's. They've been biting me. :D
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I just tillered a fairly high reflex R/D osage bow. I tillered it as a straight stave until it felt like I could string it and I liked how it was bending. Then I put it on the form and added the R/D. I knew that the limbs were balanced and bending nicely before I formed it so I felt pretty confident moving forward with the early tillering. obviously after I formed it it picked up some weight so I had to do some more wood removal before I could string it. I just felt the taper and removed wood mostly evenly until I could check it with a stringer and I felt like it would be easy enough to put a string on. First brace looked good and I carried on tillering normally.
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I just tillered a fairly high reflex R/D osage bow. I tillered it as a straight stave until it felt like I could string it and I liked how it was bending. Then I put it on the form and added the R/D. I knew that the limbs were balanced and bending nicely before I formed it so I felt pretty confident moving forward with the early tillering. obviously after I formed it it picked up some weight so I had to do some more wood removal before I could string it. I just felt the taper and removed wood mostly evenly until I could check it with a stringer and I felt like it would be easy enough to put a string on. First brace looked good and I carried on tillering normally.
I like that idea. I use billets and glue the deflex in the handle. I wonder if your method would still work for me? I'm not sure whether it's the reflex giving me tillering woes or if the deflex is messing with my eyes. I guess the deflex could be giving me tillering problems too. I'm thinking it's the reflex because I made a few RD's and had no trouble until I started to increase the reflex. I'm making a straight Pacific Nine Bark just to make sure my tillering ability hasn't gone west. :D It seems to be going well. ;)
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DC, what might be giving you problems is the radical changes in string angles when dealing with a bow with curves. Every part of the limb respondss to the string according to it's current string angle. When even some mild curves are involved this radicaly changes things.
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Nobody said it was gonna be easy (lol)
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I just tillered a fairly high reflex R/D osage bow. I tillered it as a straight stave until it felt like I could string it and I liked how it was bending. Then I put it on the form and added the R/D. I knew that the limbs were balanced and bending nicely before I formed it so I felt pretty confident moving forward with the early tillering. obviously after I formed it it picked up some weight so I had to do some more wood removal before I could string it. I just felt the taper and removed wood mostly evenly until I could check it with a stringer and I felt like it would be easy enough to put a string on. First brace looked good and I carried on tillering normally.
I like that idea. I use billets and glue the deflex in the handle. I wonder if your method would still work for me? I'm not sure whether it's the reflex giving me tillering woes or if the deflex is messing with my eyes. I guess the deflex could be giving me tillering problems too. I'm thinking it's the reflex because I made a few RD's and had no trouble until I started to increase the reflex. I'm making a straight Pacific Nine Bark just to make sure my tillering ability hasn't gone west. :D It seems to be going well. ;)
I just realised that these are backed bows. Not so easy to tiller first, bend later.
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DC, what might be giving you problems is the radical changes in string angles when dealing with a bow with curves. Every part of the limb respondss to the string according to it's current string angle. When even some mild curves are involved this radicaly changes things.
Now I just have to figure out how to deal with it.
I need a week of hiding in the rafters with Marc's weasel ;D ;D
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..... obviously after I formed it it picked up some weight so I had to do some more wood removal before I could string it. I just felt the taper and removed wood mostly evenly until I could check it with a stringer and I felt like it would be easy enough to put a string on. First brace looked good and I carried on tillering normally.
DC, If you don't mind an off topic question,
Weylin, could you comment on which part of the limbs need the most wood removal after putting in the R/D to what was once tillered as straight?
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Don't mind at all. Good question. :D
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..... obviously after I formed it it picked up some weight so I had to do some more wood removal before I could string it. I just felt the taper and removed wood mostly evenly until I could check it with a stringer and I felt like it would be easy enough to put a string on. First brace looked good and I carried on tillering normally.
DC, If you don't mind an off topic question,
Weylin, could you comment on which part of the limbs need the most wood removal after putting in the R/D to what was once tillered as straight?
In the case of this bow it was the mid to outer limbs. I don't know that it would be universal though. On this bow I found the outer limbs to be a little thicker than they out to have been. Heating in the R/D just exaggerated it. It wasn't significant but that's what the bow needed once I had it braced. I don't have a ton of experience with R/D bows.