Primitive Archer
Main Discussion Area => Bows => Topic started by: Orangeman89 on March 20, 2013, 09:28:20 pm
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Hi Folks,
I would like to get some suggestions on bow dimensions for a pyramid bow. I currently have an Osage bow blank that I steamed and formed (on a caul) to have a nice deflex/reflex shape. This blank is from wood that was harvested and split into staves in January. At the time of harvest I also removed the bark, sapwood, and several rings so that I am currently one ring above the future back. The blank dimensions are as follows: 68' long, 2" wide, 1" thick limbs (except handle area which is 1 3/4" thick). The handle area is 4 1/8" plus 1 1/2" fades. Summer rings are pretty nice and the back is pretty clean. I have a true 28.5" draw and hope to have the bow draw in the 55lb. range at my draw length. My plan is to let it sit for a month or so, since I just steamed and bent last night. This should give it time to settle a little and lose a little more moisture. Then my plan is to draw out my bow and cut to rough outline. Then let it sit another few weeks before the hot box.
Sorry for all of the detail, but wanted to give an accurate description of where I'm at before I ask for dimension suggestions.
I like a longer bow and thought about 66 or 67 inches, but I don't know if I could use it out of a tree stand (my current hunting bow is a 58" laminated hybrid bow).
What should the limb width at the fadeouts be? I was going to do a straight line taper to 1/2" at the nock end and then thin the outer limbs later. Should I do a straight taper, or try to create the Eiffel tower effect on the outer part of the limb? This is my first attempt at a pyramid so I really don't know exactly how to lay it out.
Thanks in advance for any and all suggestions.
Mark
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I would go about 2 inchs wide at the fades and a straight taper to 1/2 inch. Apyramid bow is a very good design for Osage
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I cannot really help you, as I have never touched a piece of osage, nor seen any except a single 12 inch piece of firewood. it was severely rotten...
However, some things are simple-
How high is the crown? How big of a tree did you cut it from?
Too high of a crown limits limb width.
2 inches wide is WIDE for osage.
That much I know. You are going to like the bow probably.
Make the bow not too thick- the thickness is the same all the way from the handle fades to tips.
I made a mini-pyramid from oak once. it was a scrap left over from a sword.
-Squirrel
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2 inchs is perfect in my experience with Osage of course you don't need to make it that wide but it gives a nice look
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Thanks guys. The crown isn't all that severe. The tree was a good 10" diameter before cutting. Do you think a 66" bow is too long for tree stand hunting?
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Traditional archers..
"We scorned to hunt from a tree" -Saxton Pope, Hunting with the Bow and Arrow
Probably.
Traditional archers generally did not hunt from trees.
-Squirrel
I do not hunt(with bow, at least, and I dont own a gun).
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Squirrelslinger,
Huh???? Any advise on Pyramid osage bow design? Thanks.
Mark
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At that length for a osage pyramid starting your width at two of inches is fine..by the time you hit mid limb it'll only be approx 1 1/8" or so.....you can Eiffel tower the last 8-10" if you wish to do so with a pyramid....up to you. But...I'd like to know how severe of a reflex deflex shape you shaped it....a true pyramid front profile really isn't the best front profile for a more pronounced reflex deflex side profile...its usually best to carry the width out parralel to at least mid limb to have more support to the added stress and you wouldn't have to start as wide at the fades if you changed your front profile
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Blackhawk,
Thanks for the info. I will get a picture of the blank tomorrow so that you can see the amount of deflex/reflex.
Mark
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I'd make the bow 66"t/t, 1 3/8" to 1 5/8" wide at the handle and out 8" then a straight taper to 1/2" tips(for now). After a drying out period I'd go ahead and take it down to floor tiller stage. Be sure the back is well sealed!!! Please give this stave plenty of time to season. It will make a lot better bow if you do. If you already have plenty of osage, go for it but if this is your only osage stave, give it time to cure. You won't regret it. ;)
I've hunted tree stands with a 68" bow with no problems. You do have to do a little preliminary work with prudent pruning, etc so your range of movement is maximized so you can shoot the long bow from a tree stand.
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I'd go with Pats dimensions but have to disagree that you need to leave it for a long time to dry. Why will he not regret it Pat? Is there magic going on!!!! ;)
All that matters when it comes to making a bow from a stave you've dried yourself is the moisture content %. If this stave was left in my shop for years it still wouldn't be ready....thats because the r.h. in there is too high for the wood to fall below about 13-14%. If however I reduced the thickness down to floor tiller and put it in a drier place then it could be ready in a week or two.
Drying wood is not magical it just comes down to r.h. and temperature.
Only one you start getting into things like gitars, violins etc does the age of the wood matter. Also workability in it's finest sense is different in old wood/new wood.
For a bow moisture content is all that matters (assuming it's a sound stave!).
I've made bows that have shot 180fps at 10 gpp with wood that was growing a month previous....and they still shoot that fast.
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What Pat said, dimensions/sealing the back and seasoning. Yes Mike I guess their
is some Magic going on. Also Trad/Primitive folks do hunt from trees and 66 is just fine for that.I do it all the time. Ant sure where you must hunt from the ground comes from, wasn't there but will guarantee the primitives hunted from elevated positions. :)
Pappy
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That certainly is a premium looking stave you have there Mark. So I think you have several options available to you. I like Pat's suggestion. But first you need to consider what your stave has to offer at this point. It may be dry at this point, but still green. Like some of the others, I too have had better luck with well seasoned Osage than just dried. Man, I sure would like to know Mikekeswich's secret with working with green Osage!
That slight deflex right out of the handle, will, IMO, slightly hinder a straight longbow design of that length. Osage is heavy and elastic so you would want to shorten it's working limbs with a longer riser/fades, and/or that 8" rectangular section past fades and then 'start limb taper' that Pat mentioned. And since your fades are already short at this point, and you have some R/D working for you, why not put it to use.
You could cut you bow length back to 64" ntn (plenty for your desired draw length) and slightly flip the tips. Floor tiller your bow out to where your limbs are moving real good and then place in an environment that'll get you 7-8% MC for a week or so. Then put the heat gun to it and see if it's ready for forming. Lots of info around about flips the tips if you don't know already. Good luck..........Art B
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Good to see you back around, Art. 8)
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Holy crap....artsy fartsy is baaaaaack!!!!!! :) :laugh:
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Decided to take a break from my meds! ;) How you guys been?
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Thanks Guys!!
I was wondering what the advantage to the 8" parallel limb is out of the fades vs. a true pyramid. I really don't know. I was reading in TBB 4 that the "pyramid" or the " Enhanced Andaman -Holmegaard" design were two of the better performing designs and just thought that I would try the pyramid first (easier tiller). The information is under the chapter on Design and Performance Revisited. There is a picture of two designs: "Enhanced Andaman-Holmegaard" and "Pyramid" on page 120.
I have built four bows to completion so far. All have been similar to the one suggested by artcher1, except they have all been between 66" and 68". The parallel limbs have been anywhere from 4" from the fades to all the way to mid limb. I really like them except they have all been around 1 3/8" or smaller in width out of the fades. I have therefore ended up with bows between 42lbs. and 50lbs which is fine. I just want to get around 55lbs. The staves dictated that I go that thin.
I guess my idea was to make a bow that was similar to the pyramid and the Holmegard. My intent was to have the last 8" to 10" of outer limb be non-bending and this would in effect shorten up the working limb? I sort of wanted something different than what I had been doing that followed the principals laid out in that chapter and also looked cool like the two bows pictured on page 120. I added the slight deflex/reflex because I saw the Molly (lever-bow) bow that Misslemaster showed here a month or so ago and thought that it was the cat's ass. So I figured I would incorporate that into my design. Plus it seems like that last few bows Blackhawk has displayed had the deflex/reflex profile as well. I even thought that depending on what all of you folks came up with, I might end up sinew backing the working part of the limb and really making the non-working outter limb very thin and stiff.
I am hoping you guys can help me design a monster that is really cool, shoots good, and might actually hold together :). If it doesn't hold up, I have two more blanks that look just like the one pictured except they haven't been steamed and shaped. Am I on the right track??
Thanks. Mark
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Here are a couple osage bows that I made a couple years ago at MOJam and I think both designs would fit that stave nicely. The more narrow bow was super dense osage so it's quite narrow and heavy. I think the pyramid one is more what you're looking to do.
http://www.primitivearcher.com/smf/index.php/topic,27644.msg368851.html#msg368851
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Since Osage is better suited for a narrower design because of it's density/weight/elasticity, starting further out from the fades (like 8" or so) will give you more width at mid-limb for better lateral stability for a longer bow that you're wanting. Your problem, from what I see at this point, is that the reflex you steamed in isn't going to hold and you're left with a straight deflexed/string follow bow unless you heat treat that back in. So now you need to design you limbs around the deflexed handle for best performance.
Personally, I think 66-68" is too long for a R/D design. As I see it, the purpose of this design is to leverage the inner working limb and you can only make limbs so long before their physical weight becomes a factor (as in hand shock) in this design.
I noticed Baker didn't use Osage for his" Enhanced Andaman -Holmegaard" design. Hickory would be my choice also......Art B
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Artcher1,
Thank you for the response. I am not opposed to going shorter, just haven't done it yet. The form I have has about 3.25" of reflex in it. The reflex didn't hold so well on the steamed wood, but the form did work great on taking out the propeller twist and straightening out the limbs. My plan would be to use dry heat and cold clamp the bow just after I get the limbs bending abit. On the last bow I built, I used the same form which gives about 3.25" of reflex. After tillering and shooting a hundred arrows or so, and also leaving it strung for 3 hours at a time, it seems to be holding one inch of reflex when I hold it against a wall. I am hoping that by getting the wood into the general deflex/reflex shape when green, it will be less stressful on the wood when I use dry heat to put full reflex into the limb and temper the belly abit. The only reason I haven't tried something shorter is because I was worried about overstressing the limbs, and I also haven't had a blank that I could get more than 1/3/8 width out of. Now that I have a few clean blanks with 2" inches, I am looking to get a little more radical in design. From what I read, if any wood can handle lots of minipulation, it would be Osage (which is good cause that is all I have). Again, I thank you for your insight and feel fortunate that I have folks like you to give advise and also play devil's advocate, etc. I have been home sick the last few days, so I have really been struggling with cabin fever and this site has been a great relief in that respect. Keep the opinions coming please. I promise I will take pictures of what I end up with whether it be good or bad.
Mark
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Mark, good Osage will easily handles higher weights even at 1 1/4" width. But fresh wood a little wider is prudent I think.
You'll need to crown/radius the belly of fresh wood more so that seasoned wood when heat treating to prevent cupping. Heat shrinkage is greater when using fresh wood I've noticed. Heat treating the outer limbs really well will make them lighter and more rigid also........Art B