Primitive Archer
Main Discussion Area => Bows => Topic started by: BowEd on April 22, 2011, 10:47:42 am
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Hi I'm a little knew to this forum but I was wondering if someone out there has some repeated success with using black locust as the core for a bamboo backed bow.I have a bunch of nice black locust staves.In the bow wood section of TBB 4 it says that black locust is a little touchy about its' belly.I was wondering whether a bamboo backing on it would work good.I've done one R/D BBO and really like the smooth draw and speed of it.I have some pignut hickory cores too but am curious about black locust since it is very close to the density of hickory.Love these natural wood bows to death.
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As strong as BL is in tension, I'd not worry about backing it with bamboo unless you just "have to". The belly will be overpowered by the boo to some degree, so you'll need to get the tiller as close to perfect as you can, and it'd be a good idea to trap it a bit. If the staves are nice you might be further ahead to use them for selfbows or trade them for some ipe or osage lumber to make your boo backed bows. Just my opinion, freely given and worth as much as you paid for it ;) ;D
Darcy
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Yes your right about the strength of tension in black locust.These staves here are really nice for self bows but it's a speed thing I'm after reducing the overall mass weight of the bow limbs with a relfex deflex bamboo backed design.I've been making mostly self bows out of osage and like em,Never made a self bow out of black locust yet.Maybe I should do that first to get used to the nuances of black locust.It's about the same in density as hickory and everyone says hickory backed bows are the cats ass.Hav'nt made a self bow out of hickory either.LOL.I'm having a hard time understanding whether the bamboo backing relieves compression or not.That's my delima.Thanks a lot for your input and viewpoint...So many ideas...So many bows...It's a blast !!!!
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Right now I'm thinking since a design of a flat belly and a crowned back is best for a black locust bow according to TBB 4 that bamboo on black locust might not be the best idea unless really trapped like you said.But...maybe heat treating the belly of it before applying the bamboo might work.I've got osage staves too and it really would be silly I guess to messs around from old reliable forgiving osage or hedge as I call it.I am gonna do a pig nut hickory bamboo backed one for sure though.The jury is kind of out yet on hickory too as far as compression and string follow goes according to TBB4.Don't know whether it absorbs moisture more easily than other woods or if it' weaker in compression than its belly.If hickory is weaker in compression and so is black locust, and hickory makes great bamboo backed bows why would"nt black locust?
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My first thought says no don't back locust with bamboo as locust frets easily itself
I have not tried to heat treat it yet so maybe your on to something there
Please try it and let us know how it goes
I am not into bamboo, but if I get some locust I think I may heat treat it to see how it goes but proply no boo for me
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Yes heat treating black locust might work but it might lead to a tension failure,so bamboo the back might be the ticket.Trying to get those 15 to 20 more feet a second out of an arrow is a challenge.Looks like right now a lifetime challenge..LOL.It is a lot simpler to just use old hedge and be done with it.Might be a while till I get back to you about that heat treating black locust thing but you never know.To me bamboo is a great thing to use.Got about every kind of native good bow wood around me here in southern Iowa.Get a kick out the thought of going outside cutting a stick and taking game with it.I use my bows for hunting deer,turkey,bunnies,squirrels,and maybe an occasional ground hog.Practice,practice practice....Completely different sinerio shooting at a target compared to a wild animal.Every position used.My speed thing is about getting a pass through on the bigger game.Two holes..more blood.Flat shooting.A well placed shot does the trick.Flint arrowheads.Cane and bamboo shafts.Mother natures carbide.I'm not completely traditional with sinew string and all and only hide glue.Super glue,smooth on,tightbond III are my choice,but I do love these wood bows.I put my time in the woods in the past competition coon hunting for twenty years,buckskinning a lot,brain tanning etc.,but only been making bows and arrows for a couple of years,.This is a great sport and forum.Thankful it exists.
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Anytime you glue a backing on that is stronger in tensile strength than the wood you are backing, it will strain the belly more. If you glue in some reflex, you can counteract some of that as the glue line will store some energy as shear type stress taking some of the strain off the belly.......in theory anyway.
As for speed, I just chrony'd a certain hickory self bow, that may or may not be for the trade ;), and at just under 10grains per pound it casts an arrow 175fps. This is a straight stave self bow. That's fast enough for me. ;) ;D
Darcy
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You bet.175 f/s is fast enough for me too.Sounds like a good hickory bow.Did it take much set and what were the dimensions if I may ask?
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OOPS wrong conversation.LOL
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Yes I think your right about the glue line relieving the stress.It's hard to beat a good old straight self bow that's for sure.For everything...durability,performance,and what I like too is that they shoot pretty darn quiet too compared to other bows.Like say an aluminum arrow flying through the woods...Sounds like a junkyard going through there.Ai'nt natural....LOL.
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Tension failure should not be a problem with BL. Compression failure is more apt to happen and especially with a strong backing like boo. I'm sure a boo backed BL is possible but it wouldn't be my choice of backings. If you have a good stave of BL make a selfbow. If you want a high performance designed bow use more appropriate components like boo or hickory backed osage or ipe.
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I think your right there.It was a question a friend of mine put to me and I just asked it here from you guys.I'll just make self bows out of this BL..probably a D sectioned D bow about 64" to 66" I think.With the crown being on the back of the bow with a flat belly.Just use my pignut hickory for some bamboo backed bows.
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Why not a high performance selfbow?
Darcy's bow is a good example, and all Tim Baker's writing seems to hold that an Eiffel tower tip straight selfbow with low set can reach 170-175 fps at 10 gpp without too much difficulty. I've made some that were exceptionally quick like that myself. Badger says that given equal reflex, a straight bow of that design can actually match a R/D bow, but of course would be under less stress. If you backed it with boo and induced Perry reflex you could get another 4 or 5 fps out of it, and if you tempered the locust before you glued the backing on you could reduce the mass for another few fps. Higher performance BL bow without the high stress of R/D?
Marc also built at least one R/D BBBL that I remember, so it obvisouly can be done. Just need to be careful.
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Ed, depending on where you live and what your climate is boo backed hickory might not be a good option eiother. Hickory is very strong in tension but not so strong in compression. If you live in a high humidity area the M/C of the hickory can cause excess set when paired with a boo backing. In Arazona or Utah where it is relatively dry all the time, boo backed hickory would make a fine bow. That is one of the combos that Dan Perry uses for his world class flight bows but he lives in Utah and does the flight shooting in the arid South West.
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Kegan, I have a holmgaard type osage bow here that does shoot pretty fast here,also a R/D BBO that I think shoots faster myself but I've got to get a chronograph.....LOL
Pat I'm gonna seal my BBH good I figure.I live in southern Iowa but really try to keep my house around 50% humidity in the summertime,of course the winter is always dryer than that.Your right though about the hickory taking on more moisture especially than osage.LOL.I'll find out.At this rate I'm only gonna make bows out of osage and that's it...LOL
Hey I was wondering how does a person send a picture on this?Of bows I mean.
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Sorry I'll ask the head honhcos once of PA.
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I hear ya though Kegan about the high performance self bow. I'm gonna do some perry reflexing too and see what happens.
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You bet.175 f/s is fast enough for me too.Sounds like a good hickory bow.Did it take much set and what were the dimensions if I may ask?
I'll get to that in another post as soon as I get-r-done, I don't want to give too much away as it IS my trade bow ;) I will say it is not long for the draw length and not wide for the draw weight, but follows the string by less than 1.5". Belly is heat treated.
Darcy :)