Primitive Archer
Main Discussion Area => Bows => Topic started by: BarredOwl on August 01, 2014, 12:01:27 am
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I am working on my second attempt ever at a self bow now that I have a piece of wood dried down. It is a short piece of hackberry that I split off the side of a better stave. It will be 48" nock to nock and probably not near wide enough for hackberry but it is about 1.25" wide through the middle 1/3 tapering to 1/2 at the nocks. The design may not be any good but this is just a scrap that I am using to start getting a feel for all the processes and if it turns out to be a shooter even if i have to reduce it down to a kids bow I will be happy. If I can get 40# out of it I may try to stick a deer with it. I am shooting for 40# at 22" of draw maybe a little more draw length if you all think I might be able to get it. I have it on a very short short string now. I have to flex the bow a little to get the string on the nocks and it settles to a brace height of about 1/2" after the stretch comes out of the string. I set the end of my tillering stick on a bathroom scale and pull it down to what would bend the bow to maybe be a 4" brace height and it is weighing 22 pounds depending on how consistently I hold the string down. Do you guys think I should be full braceing it at this point? I was using the 3 lbs/inch of draw theory figuring starting out at 4-5" brace height and pulling to 22" draw would be 18 x 3lbs=54 lbs which hopefully would leave me room to tiller and still hit my 40# finished weight IF things go well.
Am I thinking wrong by using the 22#weight as a base line for the starting point at a 4" brace or when it is braced to 4" and I pull it the first inch will it be way more than 22# + 3# for the first inch or will the first inch of draw be less than the 22# I am getting right now with the relatively short "long string" pulling the bow to what would be about a 4" brace? Hope I asked that clearly enough to follow.
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I'm not sure I completely understood all of that, but if you're getting 5" of tip movement with only 22# for a 40# bow then I think you should be able to bring it to full brace.
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I meant to say " I have it on a very short
short long string
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With the short string you have you should brace it when it reads 40# at about 18" or 19" if you are going for a 40# bow. Tip movement doesn't mean all that much. How far is your string pulled down at 20# is what you are looking at not so much tip movement.
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Here it is at about 4 1/4" brace.
(http://E:\DCIM\102KC613\102_1938.JPG)
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Looks to me like most of the bend is in the handle.
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It is hitting about 22# drawn to 12" after I braced it, which is not much more than it was pulling compared to the long string pulled to the same length. That surprised me. I would have bet it would have pulled substantially more at the same distance when braced than it did on the long string. If I do my part and the wood is capable it looks like I have a chance to hit 40# or so.
Looks to me like most of the bend is in the handle.
yeah it looks pretty bendy (maybe hingy?) in the handle to me too.
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You want it to be pulling your draw weight (on long string) at about 20 inches before bracing. Of course you tiller must be perfect before bracing it......
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You want it to be pulling your draw weight (on long string) at about 20 inches before bracing. Of course you tiller must be perfect before bracing it......
I didn't know that the tiller needed to be perfect before bracing. The overly bendy handle was not showing up on the long string. Have I gone too far or can it still work out? There is a small kink in the bow near the handle that is contributing to the appearance of it bending too much in the handle I think.
I am still trying to figure all this out of course. I have seen a lot of posts that say get it off the long string ASAP. I did not realize that meant "as long as the tiller is perfect first". I better get a pully rigged up so I can pull the thing and see it without having hook it on a tiller stick. It looked to be bending evenly to me all the way across. Guess that's where the experience level makes a difference.
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I would give it a good thorough toasting before I went any farther. It will help ward off some of the set that it will take without it and increase the draw weight a bit. Now your tillering toward the end point instead of adding it later and changing things up.
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Thanks, I was planning to try my hand at heat treating before I went any further. If I don't forget what to do next. I have the lower end Wagner heat gun with low and high settings. Sould I use the low or high setting?
I am having to really think my way through this. I am realizing there are a lot of things to keep in mind all at the same time. I am sure you guys do it too but I would guess you do and see many things without consciously thinking about it.
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When everything is bending evenly and together, like with every other stage of wood bow building. ;)
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Mine has a dial. For tempering I typically set mine at 7ish (1-10). I start in the center of the bow and work slowly toward the tips. A good darkish color for my money on Hackberry.
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we all have slightly different ways of working, but most of it works out the same.
I go by tip deflection, Badger goes by draw, but we had a long discussion on another thread and it all worked out much the same.
I wait until the tips are coming back about 6". But like Mike says, that's with a good tiller!
The tiller can change a bit once braced as the pull is at a slightly different angle. So once braced you need to keep a carefull eye on it as you apply that full weight again.
40# on a braced bow is a lot more strain on the wood than 40# on the long string.
I've had a Warbow 100# on the long string no prob.... brace it and it exploded at 100#
Del
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So it sounds like maybe the over bending handle issue might not have been showing as much on the long string as it did when braced? At least not enough for an inexperienced eye to notice.
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A long string will give a false reading that why you want to get to a shorter string ASAP or start with one just slightly longer than the bow.
When working a bendy handle bow I leave the handle area stiff until the rest of the limb is bending well then, and only then would I work the bend back into the handle area. I like to feel the handle bending only as I reach full draw. That way you are assured the handle won't end too much. The handle area and fades get most of the stress due to the leverage of the limbs.
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Before I brace, the limbs have to be bending properly with a good tiller and the potential finished weight has to be no more than 15# over.
How do I determine that?
I use the long string; the length of which is not that important to me but is about 10" longer for a bow 62-66" long. For a bow that size I look for 10" of string travel and 5# over draw weight.
Then I string it.
For a 48" bow, I'd set up a proportion and look to get around 7" of string travel and 5# over draw weight. This is meant to be an estimate.
Here is the proportion I used. 66/10=48/x
Here is my site.
http://georgeandjoni.home.comcast.net/~georgeandjoni/index.html
Jawge
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ok its not that complicated,,,,,, just dont take any wood off the handle area,,, then even the tiller the best you can with your level of experience,,, you have to bow braced,, it is not broke,,, it may not turn out perfect,,, just see what you can do,,, learn from that,,,, just dont draw the bow much till you get the limbs working a bit more,,,, you can do it,,, :)
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You got it braced and it doesn't look too bad...right limb in pic is a little weaker than the left so it's bending a bit more...needs more off of the left to even it (before you pull it at all)....stay away from the center and only remove from the outer 2/3 of the limbs for a bit until the tips come around more..... edge thickness taper doesn't look too bad from what I can see in the pic. Go slowly at this point and you got this....continue on
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I think I have it bending better in the limbs now but still thinking it may be bending a little too much in the handle for no further than it is being drawn. Tiller stick pic is at about 14.5". It is weighing about 22lbs at that length. It is starting to follow the string about an inch after unstringing. I have scraped through all of the darkening from heat treating. Should I have heat treated again before pulling it?
I wonder if the set back in the handle of some of the plains bows was a remedy for excessive string follow?