Main Discussion Area > English Warbow
Blacksmith's *s'Gretel* 78" Yew Warbow +125#@32"
Heffalump:
--- Quote from: Ruddy Darter on November 25, 2015, 05:13:46 am ---"Ruddy - Wood at a given thickness can only bend so far before it takes set. Fact! You make that piece of wood thicker and it can only bend to a lesser degree before taking set. Make your piece of wood thinner and it can bend further....again these are simple plain facts!"
Thanks for the info, very helpful... I've often wondered why bows are bigger in the middle and thinner at the ends, clears up that little puzzler for me. 8)
Ruddy Darter.
--- End quote ---
Consider yourself educated...."FACT" ::) :laugh: :laugh: :laugh:
John T. ;)
Marc St Louis:
--- Quote from: bownarra on November 25, 2015, 04:00:55 am ---Ruddy - Wood at a given thickness can only bend so far before it takes set. Fact! You make that piece of wood thicker and it can only bend to a lesser degree before taking set. Make your piece of wood thinner and it can bend further....again these are simple plain facts!
Now look at an elb......notice the large thickness taper. Apply those facts to a tapering piece of wood.
The tiller shape for an elb should have a little bend through the handle (depending on what you want the bow for, target only a little less bend is ok) and as the wood gets progressively thinner towards the tips the bend should be increasing proportionately.
Marc - the bow should take more set in the outer limbs? Why would you want set in the inner limbs? Any set there would have a negative effect on string tension and therefore performance. All this talk about getting this part or that part of the bow to do more work is a misnomer the whole bow should be working evenly. EVERY part should be strained to the same level, afterall wood doesn't know where it is on a bow it only knows the strain it is feeling and will respond accordingly eg. set or not. I don't hold with what you say about the part where there is most wood should be doing the most work. If you did a strain analysis of this bow I bet you would see that the inner limbs/handle area is doing plenty of work! My guess would be about the same strain as the outerlimbs. That handle area cannot bend much because if is a thick piece of wood BUT you can bet your bottom dollar that it is strained it certainly isn't sat there doing not much.
It's not a compettion of who's made the most bows you know! I only said that because I see a load of comments from people who clearly haven't made what they profess to know about and I was just quantifying my statement. I won't comment on things i'm not certain about.....I'm sure you have made many bows and are very good at it! ;)
--- End quote ---
You seem to be under the misconception that an ELB's limbs are getting a progressively thinner to width ratio as you move towards the limb tips but this is not the case. What you should be saying is that wood at a given thickness to width ratio can only bend so far before it takes set...Fact. Increase the width of the wood and you can make it thicker and that is what you have when you make an ELB.
It is very odd that you would misread what I wrote. At no point did I write that a bow SHOULD take more set in the outer limbs, only that this bow did. I have examined many old bows that were tillered as you suggest and in all cases the bows took an excess of set in the outer limbs, clearly an indication that this is not the way to tiller a bow for longevity. It is curious that you would say " EVERY part should be strained to the same level " since that is what a full compass tiller does. You can bet all you want but the fact is that no strain analysis has been done, and I would bet that if it was done it would show just the opposite ;).
In any case, do yourself a favour and contact some people that have been using bows tillered like this for a period of time and ask them for their honest opinion. I have heard from some of them and the report they give me is quite contrary to what you are trying to say here.
Marc St Louis:
--- Quote from: Heffalump on November 25, 2015, 06:01:51 am ---
--- Quote from: Ruddy Darter on November 25, 2015, 05:13:46 am ---"Ruddy - Wood at a given thickness can only bend so far before it takes set. Fact! You make that piece of wood thicker and it can only bend to a lesser degree before taking set. Make your piece of wood thinner and it can bend further....again these are simple plain facts!"
Thanks for the info, very helpful... I've often wondered why bows are bigger in the middle and thinner at the ends, clears up that little puzzler for me. 8)
Ruddy Darter.
--- End quote ---
Consider yourself educated...."FACT" ::) :laugh: :laugh: :laugh:
John T. ;)
--- End quote ---
I do believe Ruddy was being facetious :laugh:
Ian.:
I hardly ever post here anymore because most that needs to be said is said. We can always improve what we do given diminishing returns, but we know what works and what doesn't. Excess wood doesn't work for performance. Michael's bows are nice but I would agree with Marc sentiments. Let's not judge a bowyer on the basis of pretty picutures; f.d curve or distance records are a far better indicator. Even set is difficult to really see in a picture let alone measure, I would say sero inches of set is good, if you get any more than that you can do better.
bownarra:
Marc - you said i've misquoted you and then you misquote me multiple times....its hard to compare apples and oranges ;)
You are wrong about the width part of what you are saying - width has nothing to do with how far a piece of wood can bend. Also ELB's don't have to made with any given width taper like you are suggesting, in fact that doesn't even make sense.
I spent quite a few years studying the equations and theory relating to these sorts of things. A beam that changes thickness (even if the width also changes proportionately) but is bent to an arc of a circle is NOT strained evenly I can assure you. Plenty of stress/strain analysis has been done on every conceivable shape of beam and the physics behind it isn't wrong! A little searching will back up what i'm saying here.
Ruddy - If you want to write remarks like that when somebody has taken their time to try and help you understand things which you appear to not really a have handle on that's totally fine but I won't be wasting my time again.
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