Primitive Archer
Main Discussion Area => Bows => Topic started by: simk on February 25, 2018, 01:00:31 pm
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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 :BB
Thanx
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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.
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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.
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I made a working recurve using tempered HHB. The recurve slowly pulled out over time
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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.
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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?
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Not sure what the connection is?
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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/ (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 ;D
Pat: Kerfing actually makes sense (but is associated with other difficulties) :BB
Willie: Right, Steaming and heat bending is not healthy for the wood.
maybe i'm wrong. Cheers
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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.
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Eric, was the second sinew backed also, or a self bow?
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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.
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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]
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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!
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Willie, selfbow, no sinew.
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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.
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That is still a substantial amount of possible movement.
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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.
That's how I see it, Steve. I also firmly believe a person cant claim anything works just fine until a bow has no less than a 1500 shots through it. What works and look great for full draw pics doesn't always translate down the road of shooting. I've learned that lesson plenty of times now in many different areas of building bows. Right about the time I thought I had out-smarted something, longevity sneaks in and hits you in the face with reality.
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I've seen static recurves with spined kerfs but not working recurves. ???
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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.
+1
To me, It depends on how much work you classify as working recurve. I don't view a working recurve as pulling the recurve flat when you draw it, but rather just ever so slightly unwinding. I also think radius applies a lot. I mean we've all seen working Reflex/Deflex bows were it pulls out straight but effectively curls back when it returns to brace, but that's a much larger recurve radius (so much that it just gets called reflex). I don't think you're going to get much work out of a 2-inch radius recurve without breaking it or getting it to permanently lose some of its bend.
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I also think limb material, and how the recurve was achieved plays a role. Better material like Osage can handle a greater un-bending recurve without getting set per se, this is also why I think it's possible to get completely unwinding recurve out of Cough(fiberglass). But it might not all be set. It's more likely that you're loosing that recurve due to losing the bend you put into it. Some methods may prove more "lasting" than others. Which methods those are I couldn't say. I would think something like boiling or steam would hold better than dry heat but I have nothing to back that up. I also think that the thinner the limb is before you recurve, it will help it stay put. Maybe longer steamings/boilings or even repeated steaming/boiling will allow it to hold better. Who knows? Someone should do a study and experiment with that. I think it's safe to say that Perry reflex holds better than steam, boiling, or dry heat. This is another advantage to those forbidden bows you see in shops, because those curves are not only supported by cough(fiberglass), but also achieve those bends by lamination. So you may be onto something by splitting the limb like that.
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I am single minded when I hear "recurve". To me that means static with 70-90 degree tips. Everything else is simply reflex. That being said, I know alot of folks categorize sharp reflex as "recurves". So, depending on what side of that you stand on, working recurves can be very possible.
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Well said Pearl. Arvin
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Many thanks for all your contributions to this topic, which obviously can't be clearly divided in black/white. But I've learnt a lot...
One thing I'd still like to remark: When a bow looses artificial recurves/reflex it's not becoming "set". "Set" IMHO is, when wood is being overbendt and the structure doesen't return in it's naturally given position. I'f artifiacial reflex/recurves get lost by the time, the wood is returning in it's naturally given shape. It's not the same...artifiacial reflex/recurves are negative set.
And yes, i'm looking forward to present a nice pic of the bow after 1500 arrows.
Cheers
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I am single minded when I hear "recurve". To me that means static with 70-90 degree tips. Everything else is simply reflex. That being said, I know alot of folks categorize sharp reflex as "recurves". So, depending on what side of that you stand on, working recurves can be very possible.
The old rule was if the string had contact with the limb then it was a recurve. Anything else was reflex
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Mark, as far as I know that is still the distinction.
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Many thanks for all your contributions to this topic, which obviously can't be clearly divided in black/white. But I've learnt a lot...
One thing I'd still like to remark: When a bow looses artificial recurves/reflex it's not becoming "set". "Set" IMHO is, when wood is being overbendt and the structure doesen't return in it's naturally given position. I'f artifiacial reflex/recurves get lost by the time, the wood is returning in it's naturally given shape. It's not the same...artifiacial reflex/recurves are negative set.
And yes, i'm looking forward to present a nice pic of the bow after 1500 arrows.
Cheers
Set is any damage to the wood fibers that cause it to "stay bent" in any degree. It doesn't have to be string follow (which is deflexed limbs that remain in front of the belly, whether deflexed naturaly, by heat, or by set doesn't matter). It's possible to have 4 inches of natural reflex but end up with only two inches in the end. In which case you most likely got 2 inches of set, but no string follow. However, there is another occurrence where a bow can lose reflex and have it not be set. It's just undoing the reflex that was induced so to say and doesn't result in cell damage like set does. However distinguishing between that and set can be difficult. If it returns to its shape after time it's set. However, if it doesn't return it's more likely that other occurance, but it could also still be set. So to summarize again. if it returns it's set, if it doesn't it isn't necessarily not set, but could be the other occurrence (we should make a name for that).
This naturally relates to recurves because recurves are made of wood too. Just because they are recurvea doean't mean they are suddenly above the characteristics of the material they are made of. They can still theorectically get set, break, and suffer from all the other wood like ailments the rest of the limb may experience. Usually they don't because they are usually static and left thicker than the rest on purpose. But if we are going to have a truely dynamic limb then it is no longer static, but a working limb, amd if a working limb bends too much it will get damaged and get set. If the recurve completely un-winds that is a lot of bend that limb has to work for. Hence set can occur. However, I agree that it is less likely to occur than the other occurrence you mention where it just looses the heat induced recurve. So really I agree with you completely, i just didn't want the door to be shut on set entirely when it's still theoretically possible.