Sharp vs. gradual recurves

[bubby]

A gradual bend is a lot easier to accomplish successfully.

Agreed. Every successful sharp bend I've ever done has been with steam and I go at least 60 minutes per 1/2" of thickness. Probably overkill but it's worked so far.

This curve was accomplished with dry heat by a 9 year old, while it is not a sharp static it is a pretty good hook, i think guys try to bend stuff too thick and don't round the corners or sand them, this was bent with no backing strip either

[upstatenybowyer]

That's a beaut. I kinda consider osage an exception. Do you think that could be done with other woods?

[Mo_coon-catcher]

I havmt tries it with others, but black locust can also take a pretty good bend too with just dry heat. About what bubby shows there. It just seems a bit more finicky than osage, essentially a more narrow line between hot enough to bend and scorching. Which means a crack and splinter at the burn. With steam and assistance heat from a heat gun you can take BL to a 90* hook on a 4"diameter curve with mild splinters.

Kyle

[bubby]

That's a beaut. I kinda consider osage an exception. Do you think that could be done with other woods?

It could definitely be  accomplished with hackberry, it bends super easy,

[upstatenybowyer]

Never tried hackberry, but I'd like to. Heard it's one of the best for bending.   

[BowEd]

Gotta check into that hackberry.Fuel for the fire heh???

[loon]

The Bob Kooi papers address this. Sharper angles store more energy but lower angles are more efficient. Clear?

Is that because sharper requires more thickness due to stability, or just because? Guess I should check out those papers again... yeah, they're pretty hard to digest.

Guess it kind of depends on what gpp you intend to shoot, too.

From what I understood reading, Adam Karpowicz says sharp is better (like in Turkish bows) because, basically, a straight line is shorter than a curve..  (Doesn't seem like it'd be a big difference though...)

I like in-between, more pleasing to the eyes. My beauty ideal is something like a Korean or Crimean Tatar bow...

[simson]

+1 what Pearlie said.
For me it belongs also on the wood species, I got only with osage and yew really sharp hooks.

[BowEd]

Reading up on Bob Koois results is quite filling there.I keep wanting to get to the bottom to see the final bottom line results without reading fully to see how he gets there.Taking his word for it I guess.I only went through in high school through Algebra 2 I think or maybe more.That's been 43 years ago too.

[upstatenybowyer]

Reading up on Bob Koois results is quite filling there.I keep wanting to get to the bottom to see the final bottom line results without reading fully to see how he gets there.Taking his word for it I guess.I only went through in high school through Algebra 2 I think or maybe more.That's been 43 years ago too.

Me too Ed. I think I pretty much understand the bottom results and that's good enough for me!

[BowEd]

Is the conclusion yet then that the static needs to weigh more compared to working to make the difference in efficiency like what's been said before in the past?

[Badger]

       I think one thing to consider here when looking back at the old writings is that most of the well established bowyers on this sight have allready exceeded kooi's expectations. R/d style long bows as well as all types of recurves. One thing that most agree on is that the bowyer who gets the most set back in the limbs successfully without breaking down the wood will usually have the fastest bow regardless of design.

        My feeling about recurves is that extra wood in the outer limbs is required to keep them stable and not twisting. That may not be true for everyone. But just based on that the extra energy storage attained may be lost in efficiency. We will always have exceptions. Some guys can pull off impossible designs but for most of us they are not practical. As Pearlie mentioned earlier the difference between a solid well made efficient bow and a hot rod is relatively small, a lot of fun to chase but not if your main objective is a good reliable bow.

[Jim Davis]

I respect simplicity. For me, any possible gain in efficiency (which I'd have to see to believe) in a recurve is totally outweighed by the added difficulty of making one.

The only reason I can see to recurve the tips is to get a better string angle on the nocks of a short bow.

[upstatenybowyer]

I hear ya Jim. The plum ALB I just finished up is about the sweetest shooting bow I've ever made. 

[PatM]

Sharp statics have cleared 500 yards in both self and sinewed models. What's the straight or gradual curve record?