Primitive Archer
Main Discussion Area => Bows => Topic started by: Chippintuff on March 28, 2018, 09:07:41 pm
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I've been unable so far to find a typical recurve radius, so I am asking what is a good size? I'm not going to recurve my first bow, but if that one works well, I may try to recurve one soon. Is 6" too tight for most bows and new boyers? Is 8"-10" a better curve? I am working on 66"-69" staves of osage.
WA
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A quart paint can is a good size but it also depends on the length of the recurve.
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I am going to guess that PatB is speaking of a static recurve? maybe like something like this?
http://www.primitivearcher.com/smf/index.php/topic,62668.msg878994.html#msg878994
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At this point, I don't really know the difference between a static recurve and some other recurve. I think the recurves on R/D bows flex, but they appear to be a bigger radius than some. Which type does more for arrow speed?
WA
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At this point, I don't really know the difference between a static recurve and some other recurve. I think the recurves on R/D bows flex, but they appear to be a bigger radius than some. Which type does more for arrow speed?
WA
since you were asking about larger radii, I wasn't sure. In a nutshell, static = nonbending, vs working for what is seen more often in a glass, trad or laminated wood bow
here is a recent thread you might find interesting
http://www.primitivearcher.com/smf/index.php/topic,62723.0.html
I am going sit out the "Which type does more for arrow speed?" discussion
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Good Morning (-;
What I've learnt so far is, that the prototype of a completly static recurve does nothing to arrow speed but is only a geometrical issue (that helps a short bow to keep the string under 90 degree). This is the flipped tips...
Bigger recurves always work more or less and so also do more ore less to arrow speed (they save energy); the bigger the radius the more/easier they work. Usually it's not black/white but a kind of grey...
If your stave is 66"-69" you basicly don't need recurves for a draw length of 28" - but if you do, it (positivly) affects the draw curve and gives the bow a smoother draw (i think) and sure it gives the bow a cooler look (-;
Cheers
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I had a hard time bending recurves at a radius sharper than 5 inches (I used a 10 inch diameter plate). Anything sharper than that I almost always had splinter lift off, but I was not using a metal strap as well as using kiln dried and other difficult to bend wood.
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I made my first form using a quart paint can and a 2 x 6. I've used it on every static since with nothing but great results.
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I don't make as many static bows as Chris but I guess I went over board with all of my forms but I've used them all. 2" by 4"'s varying degrees of curve for the initial steam bending.Then 3/4" wide matching bent ones to temper the hooks avoiding any burning or charring on the backside.
(https://i.imgur.com/0TDgIwV.jpg)
I estimated this to be 70 to 75 degrees
(https://i.imgur.com/nQ0665l.jpg)
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This is just my theory but looking at it from a performance view I think the bigger the better but you start running into stability problems.( The limbs try to bend off to the side) You can compensate for that with some deflex in the handle area but there is a point where you spend more time trying to get the string aligned then you do actually tillering. Tillering them can be tough too.The bigger the radius the more likely they will work rather than be static. You have a picture in your head of a nice curve in your bow but you have to keep in mind that the big curves use up a bunch of the available bend. Your final tiller may end up with the limbs being straight. I've been pushing the limits on this the last two bows and they both broke. I'm regrouping now ;D
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I see different types of them as useful onto different length bows.According to health and length of their working limbs.
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This is just my theory but looking at it from a performance view I think the bigger the better but you start running into stability problems.( The limbs try to bend off to the side) You can compensate for that with some deflex in the handle area but there is a point where you spend more time trying to get the string aligned then you do actually tillering. Tillering them can be tough too.The bigger the radius the more likely they will work rather than be static. You have a picture in your head of a nice curve in your bow but you have to keep in mind that the big curves use up a bunch of the available bend. Your final tiller may end up with the limbs being straight. I've been pushing the limits on this the last two bows and they both broke. I'm regrouping now ;D
I know what you mean, lots of potential in those big hooks but they are hard to deal with. I still get the bug every now and then but I usually end up taking too much set and not benefiting like I wanted to. Most of mine now are about a 8" radius maybe 3 1/2" behind the handle, much softer, just easier for me to deal with.
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I'm a stubborn, bullheaded German. Somebody would have to prove to me big/long, static hooks are better than short, tight statics.
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I'm a stubborn, bullheaded German. Somebody would have to prove to me big/long, static hooks are better than short, tight statics.
Short statics usually do have a better outcome.
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I recently started like this
and ended (after shortening) like that
[will do some better photos later]
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But what about recurves??
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What are good radii for a bow of length 66" ntn? Also do I need to put some backing during bending and clamping?
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But what about recurves??
while tillering the limbs started to break out sideways - made m too slim probably... had to shorten it then about 5" to 59"- shoots nice :BB
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What sort of recurves were on it?
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I love all this informative discussion, and a big thanks to Willie for pointing me to that other thread. I do not know how I had missed it.
Now may I inject another question that is obviously coming from a beginner? If a bow is to have recurves, how should they be situated with the tapering width of the limb?
WA
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It can be variable,but most times the working limb stops working at least a couple of inches or more below the base of the recurve with the transition of narrowing and thickening starting there for statics.Making them wider than finished dimensions to begin with for alignment reasons,then refining and narrowing them more after tillering the bow.Many leave it the thickest right at the apex of the bend of the static too.There are many pictures of bows on here that show that.I'd suggest studying them for use of your own if you want to do it.
To me a true recurve has the string touching the belly of the recurve at brace.Everything else is just working recurve or just flipped tips a bit.They also take quite a bit longer to make than a regular straight tipped bow.
Upsides:
The looks of course right off the bat on all bows.They can raise draw weight on a bow but at a cost to the working limbs with strain unless inner limbs are deflexed a bit which helps.That's a judgement call after monitoring the condition of your working limbs while tillering.Naturally deflexed bows suit them fine.Useful on very short bows to lower string angles usually bendy handle bows and keeping the string on the tips good at full draw.Some extra performance is gotten from them too if done properly.
Downsides:
More time consuming especially making them for the first time.Dangers too.Risks of splintering them while bending.The more extreme the recurve the more critical the string alignment is.More strain on working limbs.String humm noise increases because of more string tension if not deflexed on inner limbs a bunch.More early string tension so shooting them can require more concentration to shoot them accurately compared to a straight limbed bow.
I'm sure I may have left out others too but these are the majority in my mind.All in all you might like them and a person should try one sometime to see after making a number of straight limbed bows.
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To my mind, it's about like everything else in wood bow construction; a question of balance between features. What you want is limited by imagination. What you can MAKE work is often down to skill. What you can get away with is usually limited by the material itself.
All my BEST recurves were wide-limbed, laminated, 62" to 64" long, with large diameter curves taking up a lot of limb length, curves big enough to net me incredulous sputtering from some skilled and experienced bowyers. For one I used the rim of a 12" bike wheel with a strip of masonite wrapped around it.
BUT, they were also deflexed proportionally at or near the handle, with tips only about 2" in front of the handle when shot in. This design allows for a lot of string/limb contact and thus a lot of lift off. The limbs barely move or bend to take the string, so limb strain is minimal, but early draw weight is high. The deflex improves the stability of what would otherwise be an impractially large recurve. The wide inner limbs can take the strain, with the added benefit of mild Perry reflex in much of the limb. Reverse tip wedges allow narrow, but stable tips.........
AND, I am a huge fan of string bridges. They just KILL the vibration and dampen the shot. Additionally, if properly situated you can "cheat" the amount of angle the recurve has by lifting and centering the string, causing it to lift off later in the draw.
But, this would never work if the bow wasn't deflexed, for instance. If you start with a straight stave and want it straight then small, tight recurves are the only ones that would work.