Selfbow - Dynamic (vs. static) recurves

[simk]

Hi All

In my "cheap try"-thread Aaron asked me a question i couldn't answer: He asked, if one "could make these bends without splitting the wood".....

So what do you think: Is it possible to do working (dynamic) recurves on a selfbow without splitting an reglueing the limbs? How?

If you ask european bowyers they all will say: No! Either you do them so thick that they don't bend anymore (static recurves) or they loose their reflex by the time...

As i absolutley wanted to do working recurves i started splitting the limbs and reglueing them. Would it also be possible with steam/heat? Is it a matter of the wood? Does osage work like this?

Please help 

Thanx

 

[Pat B]

Depending on the wood. With osage you can make working recurves that won't come out probably using steam or dry heat. With white woods I'd say use steam. By splitting and re-gluing you would have a hard time making the recurves work, open when drawn and close back on release.
The only recurves I ever had come out were made with hickory that I used dry heat to bend.
I've never made a working recurve.

[Badger]

  The recurve portion of the limb is no different than the rest of the limb, wood can only bend a little bit. So you can have a slightly working recurve but if you allow it to bend too much it will pull out or break. I have never seen any advantages to a working recurve but I see lots of disadvantages. Slightly working is harmless enough but too much flexibility allows a limb to distort too much on the power stroke.

[Marc St Louis]

I made a working recurve using tempered HHB.  The recurve slowly pulled out over time

[PatM]

I've had good luck with Elm steamed and then heat treated.  Kerfing actually makes sense too because you are actually moving the  gluing surfaces relative to each other.  Not sure why PatB  thinks it would not work???   A typical working recurve works well for this very reason.

[willie]

Kerfing actually makes sense too because you are actually moving the  gluing surfaces relative to each other.

realigning vs. heat bending that actually damages wood cells?

[PatM]

Not sure what the connection is?

[simk]

Hi

Pat: the kind of wood is certainly important - i just saw simson reflex osage - just a little bit of reflex...nicely done http://primitive-bows.com/buildalong-from-bow-no-91-tree-toes/

Badger:

  I have never seen any advantages to a working recurve

1. It looks great and is cool 2. For a shorter bow you need reflex 3. I don't want any unnecessary weight (static recurves) on my tips

Marc: 1:0 for the europeans 

Pat: Kerfing actually makes sense (but is associated with other difficulties)

Willie: Right, Steaming and heat bending is not healthy for the wood.

maybe i'm wrong. Cheers

[Eric Krewson]

This is probably an anomaly but I was still in my recurve mentality when I made my second osage bow. The first was a sinew backed board that was very poorly made and blew up after 30 shots.

Not knowing it couldn't be done, next I decided to make a working recurve. This was 20 years ago but I am pretty sure I copied the limb arc from a set of bighorn limbs and steamed in the curves. I used a flawless piece of osage.

I made a bow around 60# with full working recurve limbs, I shot it for a while, even placed in the TN indoor 3D archery tournament in Nashville with it.

After I made a few more osage bows I retillered it down to my wife's poundage so she could give up wheels and start shooting a selfbow, she shot it for a year or so. The recurves never pulled out, unfortunately I never took a picture of it.

I took it to a local Renaissance Fair to show it to the resident longbow maker named Mike Twaddle to see what he thought as he had over 300 longbows under his belt. He looked at me quizzically and asked "you made this, it was your first working bow"? I didn't know I had done something out of the ordinary. He shot it and told me I would go far as a bow maker.

After I made my wife another bow more suited to her I gave the recurve to a nephew who probably still has it today, it never broke as far as I know.

[willie]

Eric, was the second sinew backed also, or a self bow?

[simson]

So what do you think: Is it possible to do working (dynamic) recurves on a selfbow without splitting an reglueing the limbs? How?

If you ask european bowyers they all will say: No! Either you do them so thick that they don't bend anymore (static recurves) or they loose their reflex by the time...

Well, I'm European and I say yes it is doable, why not?
Of course not like on fg bows, but you can build dynamic recurves. Here are some samples: http://primitive-bows.com/tag/working-recurve/

In fact I see no good reason for splitting limbs and reglueing. Steaming and using cauls is way better in my eyes and you have a better control.

[simk]

Dear Sim(s)on

I'm glad you say something about this topic.

You create working recurves on your selfbows - in knew that and i adore your work.

Is it due to the wood (osage) you use or is it your magic hands? What is the mystery about (relevant) working recurves with selfbows?

Could you do the same working and lasting recurves also with hazel? yew? and in my actual case sorbus aucuparia and black locust?

Did you steam or just heat No 100?

Thanx for your time

[maybe i have review my techniques and to train and improve my basic steaming skills] 

[simson]

Osage is best bow wood ever, here in Germany or Switzerland are only a few which came very near. Such as lilac (syringia) or cornealian cherry (cornus mas). With this woods it is easier to make, but I'm sure with patience you could do with every hardwood. hazel is no good candidate.

Steam in your recurves with a caul, tiller the bow and ignore the recurves (let them stiff), when you have the bow tillered out to lets say 22" begin to scrape the recurves, go slow and go parallel (upper and lower limb).

I have improved my steaming setup the last years and I won't miss that equipment. At least every second bow is steamed (maybe I have only crude staves, haha). No 100 is also steamed.

My suggestion: search for good staves and make a nice steaming station.
Good luck!

[Eric Krewson]

Willie, selfbow, no sinew.

[Badger]

    I think when you ask the question can recurves work or not the simple answer would be that the wood in a recurve can't bend anymore or less that the wood in any other part of the bow relative to its thickness. If it does exceed a certain bend it will take set which would mean all or part of the recurve gets pulled out.