Ozbow

Neil, I have always wondered about the local cypress. You are right about the appearance of the stuff. They call it Murray Pine here in Tocumwal. It has a remarkable similarity to Yew in grain structure but a lot lighter in colour until it ages. The Yew I have here is a good bit more coppery in colo...

Colin, I don't know how I came to think of the process, but musing about how the outer limbs ought to move with the Autocad part of my brain, I thought that because some of the ELBs were made by others and began to bend in the middle too early on in the draw, I thought that if I was able to stiffen ...

Sigh !!!! Don't worry, Colin, it will colour up later with exposure to light to something like a butter colour. I like it because it is really light in the hand. And . . . I like your arrow passes too. Those I have made from Red Ash were good shooters and usually took from 1.5 - 2" of set with ...

Daryl, That is a very interesting observation about the differences between juvenile and aged woods. Curiously, my two all bamboo bows have been miserable failures where the belly was a Bamboo lamination despite being told that the material had been heat tempered. Even so, I should have learned the ...

Neil, Those dips and fadeouts look pretty good to me and I reckon you've got the idea pretty well. All of us are only trying to show you how best to avoid your bow blowing up at the limb-fladeout juncture. We don't see you as nit-picking. You are asking legitimate questions about things you don't un...

Colin,

I'm not surprised at that. It's very strong stuff with one of the highest ratings among the indigenous timber varieties. All of the so-called 'Iron Barks' rate as very strong with not much between any of them that the published figures show.

Daryl, That is a very interesting post indeed. Re the word 'plastid', I found it used by Bootle in his book - "Wood in Australia". I read its use to be a sort of generic term for a how your post describes the purpose of lignin. It seemed to refer to a group of materials having plastic prop...

Nezwin, I think we do understand what you intend to do and you are on the right path, but for a dip to convert to a working fade-out, the outer part of your dip needs to be even shallower again. That is important to know. The fade-out area is a bending area and must be shallow enough to enable bendi...

Neil,

I do understand what an hypothesis is and its purely propositional nature. Just the same, it has started me thinking too. Like you, I have thought of wood as having similarities to fibreglass and other reinforced composites.

Good post there Daryl. I have always referred to wood fibres being held together in a matrix of what I have thought was referred to as a 'plastid' which is probably technically correct, but obviously among the woodies, the fibres are cellulose and the matrix material is lignin. I always thought is w...

Nezwin, like Big Bob, I think your hypothesis has merit, despite my previous arguments above. It is perhaps the most plausible of any in regard to central stiffeners and deserves some kind of follow-up. However, the final proof of efficacy is that on average, bows made with a central stiffening laye...

If you read my post as argumentative or disagreeing to your posts I apologise I simply ment that I don't have enough experience or information to argue one way or the other. Not in the least Bjorn. I am not that thin-skinned. At no stage thus far has it occurred to me that you may be argumentative,...

Bjorn, Actually, no, I am not referencing bamboo as a belly material. I have only used that explanation to illustrate its shortcomings. I wanted to address your choice of bamboo as a central lamination and that you seem to believe that it will endow some performance enhancing properties to your bow ...

Colin, Personally, I am not surprised at the result you had with your Ipe bellied ELB. I reckon that Ipe is far superior in compressive strength than commonly available Lemonwood, at least it seems to on my two bows. Its elastic limit is probably a good bit higher than Lemonwood on average, so defor...

Colin, I would indeed be interested to know if your reference to reinforced concrete applied also to bows. My entire understanding of forces acting on bow limbs derives from the work of Hickman, Klopsteg and Nagler as you know, and your example doesn't seem to have been considered in therir work. Bu...

Bjorn, Perhaps bamboo has those properties in other applications, but its principal value in bowmaking is its low mass and very high tensile strength as a backing. But it is very poor in compressive strength except where the outer rind is used on the belly. If ordinary rindless laminations are used ...

Bjorn,

Have a read through my most recent post to Colin here - http://www.ozbow.net/phpBB3/viewtopic.php?f=34&t=15617 and see what you make of it.

Colin, For what it is worth, my personal opinion so far as I understand the theory of neutral axes is that a centralised 'stiffener' does not work at all. Central stiffeners actually do nothing except take a ride between the back and belly of a bow where the genuine mechanical forces tension and com...

Nezwin, Perry is right. The limbs should actually bend into the fadeouts, meaning that the actual fadeout bends as well. The fadeout area is actually a functioning part of the inner limb. That last blue line is still far too steep in the outer 1/3. Fadeout means exactly that - that the riser dips do...

According to whom??? Whose version of 'trad' are you referring to???

it looks to me like your limbs have quite a bit of bend in close to the handle and straighten out towards the tips.

Yep, that's what I think too, Colin.

Also, Perry is right about the rasps, etc and that tiller precedes cosmetics.

Colin, I too read that comment on Lemonwood by Richard Head but find it a bit bemusing since none of the very many Lemonwood bows in my collection, once straightened, have taken any kind of appreciable set which I have not left in them. Back in the all-wood bow days, it was renowned for being very s...

BowmanBjorn, If your bow is sealed with a good modern flexible waterproof finish, I see no reason why it should lose any cast at all. Where I live in the Southern RIverina of NSW, it gets well into the mid-40s during summer and quite often. Heat has never affected any of my bows that I have noticed....

Nezwin, I know what Dave's profession is. With backsawn timber as the belly of the bow, it doesn't matter about grain direction. That colouring is what was on my glassed bows when new years ago, but it darkens to a honey colour and looks for all the world like a lighter coloured Yew. It can go to a...

If you get over to Dave's, he will most likely show you how to do the test properly and with the numbers, he may be able to crunch them in his 10-arc app in Excel and print you out a nice set of numbers so you can profile the shape of your bow within the load limits of the actual piece of wood you h...

Colin,

That's excellent. It is really satisfying to get that level of feedback on one's work. I applaud you. You have come a very long way in a very short time indeed.

Colin, What about leaving the tri-lam as is for a good while and get used to it at its present weight before shorting it. When you are truly used to it and can shoot it effortlessly, my guess is that you will get even better distance from it. If it proves well by then, then I would short it a bit. ...

Gorgeous bend there Colin. What else to say. Have a look at this bloke's site in the US. I have a couple of his Hickory ELB in a more manageable draw weight for me. He is a very good bowyer too. http://www.ebay.com/sch/archeybowman/m.html?_nkw=&_armrs=1&_ipg=&_from= I will put up a post ...