Author Topic: Typical radius of a recurve  (Read 4561 times)

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Offline Chippintuff

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Typical radius of a recurve
« on: March 28, 2018, 09:07:41 pm »
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

Offline Pat B

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Re: Typical radius of a recurve
« Reply #1 on: March 28, 2018, 09:32:41 pm »
A quart paint can is a good size but it also depends on the length of the recurve.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline willie

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Re: Typical radius of a recurve
« Reply #2 on: March 28, 2018, 09:56:25 pm »
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

Offline Chippintuff

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Re: Typical radius of a recurve
« Reply #3 on: March 28, 2018, 10:51:20 pm »
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

Offline willie

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Re: Typical radius of a recurve
« Reply #4 on: March 28, 2018, 11:46:57 pm »
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

Offline simk

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Re: Typical radius of a recurve
« Reply #5 on: March 29, 2018, 01:37:00 am »
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
 
« Last Edit: March 29, 2018, 04:22:43 am by simk »
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Offline gfugal

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Re: Typical radius of a recurve
« Reply #6 on: March 29, 2018, 08:02:13 am »
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.
Greg,
No risk, no gain. Expand the mold and try new things.

Offline PEARL DRUMS

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Re: Typical radius of a recurve
« Reply #7 on: March 29, 2018, 08:19:37 am »
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.
Only when the last tree has died and the last river has been poisoned and the last fish has been caught will we realize we cannot eat money.

Offline BowEd

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Re: Typical radius of a recurve
« Reply #8 on: March 29, 2018, 09:43:37 am »
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.

I estimated this to be 70 to 75 degrees
« Last Edit: March 29, 2018, 10:11:27 am by BowEd »
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Ed

Offline DC

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Re: Typical radius of a recurve
« Reply #9 on: March 29, 2018, 12:32:52 pm »
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

Offline BowEd

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Re: Typical radius of a recurve
« Reply #10 on: March 29, 2018, 01:34:51 pm »
I see different types of them as useful onto different length bows.According to health and length of their working limbs.
« Last Edit: March 29, 2018, 01:45:37 pm by BowEd »
BowEd
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Ed

Offline Badger

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Re: Typical radius of a recurve
« Reply #11 on: March 29, 2018, 01:48:34 pm »
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.

Offline PEARL DRUMS

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Re: Typical radius of a recurve
« Reply #12 on: March 29, 2018, 02:17:06 pm »
I'm a stubborn, bullheaded German. Somebody would have to prove to me big/long, static hooks are better than short, tight statics.
Only when the last tree has died and the last river has been poisoned and the last fish has been caught will we realize we cannot eat money.

Offline Badger

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Re: Typical radius of a recurve
« Reply #13 on: March 29, 2018, 02:33:20 pm »
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.

Offline simk

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Re: Typical radius of a recurve
« Reply #14 on: March 29, 2018, 02:47:27 pm »
I recently started like this

and ended (after shortening) like that

[will do some better photos later]
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