Author Topic: Brace weight plus draw weight  (Read 5239 times)

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Offline hedgeapple

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Brace weight plus draw weight
« on: July 17, 2013, 03:36:38 pm »
I'd never really thought about this until last night working on a bow. But, I've never made a bow with this much of a flip on tips. I got the tips pulling 7" on a long sting @ 50#.  So a strung it with a short string.  It was then I realize how strong the bow was just pulling the string over the bracket on my tillering tree.  It was probably 40-ish #.  Of course, the scales aren't reading this weight because there is no pressure on them.  Then I started working the bow.  The thought came to mind, if there's 40# stored/unmeasured weight with just stringing the bow and I'm pulling it 40#, the limps are actually being pulled 80#.  ???

With that being said, getting a good tiller from the floor tillering stage to brace can be more critical than I initially thought as a way to reduce set.

And, maybe gradually working/tillering a low braced bow at 35# to start with until the tiller is perfect with the goal of being at my target weight of 50# at full brace is a good idea.

Your guys thoughts?????????
« Last Edit: July 17, 2013, 03:48:15 pm by hedgeapple »
Dave   Richmond, KY
26" draw

Offline BOWMAN53

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Re: Brace weight plus draw weight
« Reply #1 on: July 17, 2013, 03:45:41 pm »
Lol "the limps"

Offline Thesquirrelslinger

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Re: Brace weight plus draw weight
« Reply #2 on: July 17, 2013, 03:55:37 pm »
So you are saying you pull it #40 to brace it, then draw it another #40... so #80? it makes perfect sense.
"Insanity is doing the same thing over and over again and expecting different results"

Offline Del the cat

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Re: Brace weight plus draw weight
« Reply #3 on: July 17, 2013, 04:15:14 pm »
I've posted about this before. If you mark the tip deflection at brace onto the wall and then put a long string and measure the pull to get there. It shows the advantage you get from the tight braced string. You can repeat this at other draw lengths by going by tip deflection not draw length.
That's why my warbow exploded at 100# despite having been drawn to 110# several times on the longer string.
So basically if you want to make a 50# bow, pulling it to 50# on a long string early in the prcess isn't going to over stress it. And that's why it's important to get to a low brace early to avoid coming in under weight.
Can't remember off the top of my head but I think longstring measures about 20% higher than braced string at the same tip deflection.
By 'long' I mean just long enoght to get on the bow.
Del
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Offline Thesquirrelslinger

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Re: Brace weight plus draw weight
« Reply #4 on: July 17, 2013, 04:44:42 pm »
I've posted about this before. If you mark the tip deflection at brace onto the wall and then put a long string and measure the pull to get there. It shows the advantage you get from the tight braced string. You can repeat this at other draw lengths by going by tip deflection not draw length.
That's why my warbow exploded at 100# despite having been drawn to 110# several times on the longer string.
So basically if you want to make a 50# bow, pulling it to 50# on a long string early in the prcess isn't going to over stress it. And that's why it's important to get to a low brace early to avoid coming in under weight.
Can't remember off the top of my head but I think longstring measures about 20% higher than braced string at the same tip deflection.
By 'long' I mean just long enoght to get on the bow.
Del
So about the length of the bow?
"Insanity is doing the same thing over and over again and expecting different results"

Offline Del the cat

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    • Derek Hutchison Native Wood Self Bows
Re: Brace weight plus draw weight
« Reply #5 on: July 17, 2013, 04:47:16 pm »
I've posted about this before. If you mark the tip deflection at brace onto the wall and then put a long string and measure the pull to get there. It shows the advantage you get from the tight braced string. You can repeat this at other draw lengths by going by tip deflection not draw length.
That's why my warbow exploded at 100# despite having been drawn to 110# several times on the longer string.
So basically if you want to make a 50# bow, pulling it to 50# on a long string early in the prcess isn't going to over stress it. And that's why it's important to get to a low brace early to avoid coming in under weight.
Can't remember off the top of my head but I think longstring measures about 20% higher than braced string at the same tip deflection.
By 'long' I mean just long enoght to get on the bow.
Del
So about the length of the bow?
Eh? What about it?????
With any bow a log sting will give a flase reading of draw weight... end of.
Del
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Offline Thesquirrelslinger

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Re: Brace weight plus draw weight
« Reply #6 on: July 17, 2013, 04:48:47 pm »
Hm... that might explain some stuff- why a floor tiller bow feels sooo stiff but winds up #20 on the tiller.
"Insanity is doing the same thing over and over again and expecting different results"

Offline hedgeapple

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Re: Brace weight plus draw weight
« Reply #7 on: July 17, 2013, 05:50:45 pm »
Thanks Del.
Dave   Richmond, KY
26" draw

Offline Del the cat

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Re: Brace weight plus draw weight
« Reply #8 on: July 17, 2013, 05:58:34 pm »
Ha, I trawled through all my posts and found it...
http://www.primitivearcher.com/smf/index.php/topic,25438.msg341928.html#msg341928
The figure isn't as dramatic as I recalled but it does show the difference.
Del
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Offline Danzn Bar

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Re: Brace weight plus draw weight
« Reply #9 on: July 17, 2013, 08:19:48 pm »
Boy Dave.......... I'm go'n to have to get me another beer and read this again  :) ...............Went right over my head the first time  :o

DBar
Integrity is doing the right thing when no one is looking

Offline Cardboard_Duck

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Re: Brace weight plus draw weight
« Reply #10 on: July 17, 2013, 09:45:28 pm »
Less thinking more bow making is what I say...














Please take with sarcasm :)
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Offline hedgeapple

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Re: Brace weight plus draw weight
« Reply #11 on: July 17, 2013, 09:55:02 pm »
Duck,  haha  My philosophy is anything worth engineering is worth over engineering.  haha

I can make a pretty good, bow.  I'm just wanting to learn to make great bows  ;)
Dave   Richmond, KY
26" draw

Offline Cardboard_Duck

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  • Winter Haven, FL
Re: Brace weight plus draw weight
« Reply #12 on: July 17, 2013, 09:59:04 pm »
Duck,  haha  My philosophy is anything worth engineering is worth over engineering.  haha

I can make a pretty good, bow.  I'm just wanting to learn to make great bows  ;)

Hehe :) I know. I just let the wood tell me what its wants to do :)
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Offline Danzn Bar

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Re: Brace weight plus draw weight
« Reply #13 on: July 17, 2013, 10:15:30 pm »
Dave,
Read it the second time with a couple of more beers.
quoting you......
"With that being said, getting a good tiller from the floor tillering stage to brace can be more critical than I initially thought as a way to reduce set."

This is what I think Chris (Blackhawk)means when he doesn't use a long string and floor tillers only.  I have also heard it said, don't tiller past any flaws until the flaw is fixed.

The light just can on for me too, if my thinking is OK.  The bow I'm working on now, I'm doing more floor tillering than I usually do and paying real attention to the bend.  I may end up with less # than what I looking for on this bow, but my tiller may be better and the bow may last longer.  Which has been an issue with me in the past.  I can always catch up on the weight on the next bow.

I enjoy posts like yours........... despite what Duck says  ;)
DBar   
Integrity is doing the right thing when no one is looking

Offline Cardboard_Duck

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  • Winter Haven, FL
Re: Brace weight plus draw weight
« Reply #14 on: July 17, 2013, 10:23:49 pm »
despite what Duck says  ;)


I know I know.... I just swear my mind goes blank when I am tillering a bow, I just "listen" to the wood and trust my judgment. When I see people worrying so much about technical details I just always think K.I.S.S. No harm meant by my comments, just how I feel :)
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