A light just came on

[DC]

I just ruined the bow that was going to break 200(I wish ) 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??

[simk]

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!

[mmattockx]

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

[DC]

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 . Something that I should have learned five years ago

[DC]

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.

[Dances with squirrels]

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.

[Selfbowman]

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

[Allyn T]

I am really glad I read this.

[DC]

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.

[Mo_coon-catcher]

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

[DC]

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.

[Badger]

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.

[bownarra]

Yes

[Weylin]

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.

[willie]

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