Primitive Archer
Main Discussion Area => Bows => Topic started by: mekial2222 on August 01, 2010, 02:15:33 am
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One thing that I've been confused about concerning draw length for bows... How should I say this... why is most premade bows only 28" and less? what is the deciding factor for extending the draw length? I have a bow thats 65# @ 31" couldn't it also be called 40# @ 28"? why wouldn't I want to pull it all the way to my full drawlength of 33"? I've been wanting to make a bow that I can do a full draw sence I can't find any 33" draw ones out there. sorry I'm not sure if I'm saying this right... Is it the taper created by tillering which distributes the stress over the full length of the limbs giving the draw length/weight? so if a bow is 65# @ 31", would I want to tiller it down a little more to get 65# @ 33? or would it just break before I get there? Thanks.
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One thing that I've been confused about concerning draw length for bows... How should I say this... why is most premade bows only 28" and less? what is the deciding factor for extending the draw length? I have a bow thats 65# @ 31" couldn't it also be called 40# @ 28"? why wouldn't I want to pull it all the way to my full drawlength of 33"? I've been wanting to make a bow that I can do a full draw sence I can't find any 33" draw ones out there. sorry I'm not sure if I'm saying this right... Is it the taper created by tillering which distributes the stress over the full length of the limbs giving the draw length/weight? so if a bow is 65# @ 31", would I want to tiller it down a little more to get 65# @ 33? or would it just break before I get there? Thanks.
With most "premade" bows, the draw weight is measured at 28" because its the usually the best draw length for an average sized man. When your building your own bows you decide what drawlength you want and what weight you want at that drawlength. If you are taller or have longer arms than most men, you will need a longer drawlength. You then carefully tiller it to bend evenly to that length and weight. A lot of bows are tillered to take a little over-draw as a safety precaution, but you should be careful drawing to a longer draw-length. Bows meant for a longer draw-length usually have design considerations allowing for it, such as a longer nock to nock length or a working handle area. A bow originally designed for a 28" draw would probably break if pulled to 33", but a bow designed for a 31" draw might not. If you draw it further, the weight will be higher unless you re-tiller it, which I would recommend you do. It will be under less stress and have a better chance of not breaking. But, the best thing would be to just build one to fit you. If you need to draw it 33", I would suggest a nock to nock length of at least 70".
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Thank you for the reply... do you think I could get the draw I need and keep the bow at a shorter length by going the horse bow style route? thanks.
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The asian horesbows would be a good route but they take a lot of experience and a lot of time to make. You could buy one that would work at your draw-length. I would suggest the Magyar Sport. It can be drawn up to 32" and you can get it up to #60@28" They sell it at 3rivers archery for $415 plus shipping. I'll send you a link in a PM
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A lot of the really knowledgeable guys get on here in the mornings. The might have some better advice for you. I'm no expert at all. I just try to share what I know.
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the magyar sport from 3rivers is abit expensive. I found a u-finish for $175 or so, which is also abit much for my budget. But I would like to make myself one to stay in my budget. Does anyone know of a online source for some plans/dimensions? Is there a calculator for dimensions required for a bow of a particular style vs draw length? Also is where would I find horn? is there a more readily available substitute? how much tendent would be needed? is there a rule of thumb of this much tendent per foot? why does it take so long to make? is it for the glue to dry? are there more modern faster drying glue that can offer the same performance as hide glue? Sorry for all the questions, but I greatly appreciate it. thank you.
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In an ideal world a wood bow can be drawn 1/2 it's overall length. Under normal circumstances you should add at least 10% to that length. So for a wood bow that will safely draw 33" you should start with a bow length of at least 73" or more. With the use of sinew for a backing and horn for a belly you can go way below that bow length. The only other option that I know of if the use of fiberglass and we don't deal with fiberglass here on PA.
Another consideration would be for you to change your shooting style so a shorter draw length is used. This would be the cheapest way to go!
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What kind of bow do you have, mekial, that you draw 31 inches? Jawge
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An English Longbow of Yew, say 74" long would get you there.
At the poundage you want it wouldn't be working too hard. My 70" Yew longbow draws 31.5" at #90, and would probably come back further if I could manage it!
(Click on the WWW icon, just to the left 2nd inon in under the username, there's a pic on my home page).
BTW are you sure you draw 33" ? Most people actually draw less than they think.
Del
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i have a friend that is 6'6" and he only draws 31 inches he is shooting one of my red oak bows 70 inches long . my guess is that your draw was measured from compound standards which would be different from wood bows
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Ken75 has a point. I have measured so many guys the same height as me (5"9") claiming 30" draw lengths and the longest I have had yet was a natural 27" once I corrected some of his form errors. Many of those 30" draw lengths came in around 25".
See what you can do to get to someone that has some experience with primitive archery bows and have them work up your draw length. Maybe you are actually 7' tall and drawing 33", I could be wrong.
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I'm shooting a 72" bamboo backed ipe longbow from Rudderbows Archery. When I ordered it 31" was the longest draw they offered on their site. I'm 6'7" with a armspan of that or a little longer. I've measured my draw a couple ways, one was to hold a tape measure like a bow and hold the tab on the tape like the string and pull it to full draw position (to me this would be a accurate representation of belly to string length) and I got about 33", the second way was to get a 36" dowel rod and pinch one end between two fingers like I would a arrow and pull it across the webbing of the other hand as if I was holding a bow and than grip the dowel so it doesn't move in my bow hand than measure it with a tape measure and I got about the same as my other method... is there another way? thank you.
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put the end of a yardstick against the center of your chest with your arms straight out in front of you and hands together, fingers extended. the measurement that your middle finger tip reaches is a good place to start.
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the yardstick method is 31-3/4"...
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I do the same as walkabout....been through a lot of ways to do it since the 60's and the yardstick to the mniddle of the chest is about as accurate as your gonna find.
rich
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then you would build a bow that was pulled safely to 32", although you would only really pull it to30 by AMO standard, which is measured 1 3/4" from the deepest part of the bows handle. tillering it out to 32 inches would only be to ensure safety.
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i find that when switching to traditional archery the form changes so much that there is a signifigant diference in draw length. one reason is anchor point, another is form. if i open my chest up the whole way as i do with a compound, then i can draw to 30" easily, just anchoring to my lip. however, trad, equipment is more snap style shooting, with more of a bent elbow and wrist, and the anchor instead moving to the corner of your lip in most cases, the string being released as you meet your target and anchor point at the same time.
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The bow is built to the draw length. You have to be build it longer and/or wider. A good rule of thumb is to double your draw and add 10-20%. For woods like osage you can add 10% if youare an experienced bowyer. Otherwise stay at 20%. Jawge
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The bow is built to the draw length. You have to be build it longer and/or wider. A good rule of thumb is to double your draw and add 10-20%. For woods like osage you can add 10% if youare an experienced bowyer. Otherwise stay at 20%. Jawge
...and that is why many custom bowyers really don't carry a lot of bows in stock. The "one size fits all" concept kinda falls apart where the moccasins hit the trail. Flip side of that coin is that when you go to make your bow, it fits YOU perfectly.
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you would still be looking at around 70 inches for a safe length for a longbow with a nonbending handle. the composite bows will handle your draw length with a much smaller overall length.whether it be a sinewed shortbow or an asiatic r/d would be your choice as to what you want to build or have made for you.
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I never have used a compound bow... I've pulled afew but I've never shot one. just in general I've always thought drawlength was pretty much related to how long you need your arrows so that at your full draw your arrow doesn't fall off your bow...
So back to the main point of the thread. to set draw length you need to start with double draw lenth plus 10%-20% for overall bow lenth for a longbow? I know to make a composite you need multiple components but can one be made with easier to get materials? Logic would dictate that you can't just make a composite style selfbow and get the same drawlength to bow length ratio as a true composite...
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70 inches really isnt very long for a bow. my first bow build was a 72" longbow, and it turned out great, is still one of my favorite bows because its very forgiving. as far as building a composite, the materials can be easily acquired depending on your location. horn can be bought on the auction site for a fair price, and sinew is fairly inexpensive as well. the hard part would be putting it all together successfully. last time i was looking at materials for a composite i found out that i could get them for a bit less than it would cost someone to build a fiberglass laminate. the calculation for bow length is a pretty accurate one, although talented bowyers can build bows that break these guidelines. ive seen hickory bows that are pretty short pulled to 28 inches.