Author Topic: A question for Yew guys  (Read 4168 times)

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Offline Springbuck

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Re: A question for Yew guys
« Reply #15 on: January 09, 2017, 05:40:53 pm »
"I hate to think that laminated bow design is all "try it and see", with so   too many variables to work with on the next try."

It isn't, but it is a series of educated guesses. 

The main thing to understand with laminated bows is how to get close to what you want to begin with.  For instance, yew is very soft.  It is not very stiff.  It is great bow wood because it will tolerate a LOT of bend, not because it "adds power".  Thus, it lends itself to narrower deeper profiles (thick wood is stiffer but bends less before taking damage, but yew can be thicker than most woods and bend the same amount).  Since it is already light, this is kind of a double savings AND it can be laminated or worked as a flatter, wider limb, too, and do very well as long as it's thick enough to get the draw weight(stiffness) you want.

Also, because it readily takes compression bending, you can back it with bamboo, hickory (super stiff backings), maple or elm (medium stiff backings), or even rawhide and sinew (stretchy backings) and the yew will work with it one way or the other, within reason.

We talk a lot about backings overpowering belly woods, but bellies can overpower backs, too.  In fact, when any bow breaks, one of two things happened; the belly refused to compress and the back stretched more than it could take, OR, the belly failed, usually by fretting, and the hinged spot put a kink in the bow forcing the back to stretch more than it could take right at that tiny spot.  I mean, if we don't count things like delaminations and tips blowing off....

The bow that Del mentioned failed at least in part because, while yew sapwood is incredibly tension strong, since he had a "slat" of it, he had certainly cut through growth rings while cutting the slat.  Thus, as he says, the bow would have survived much longer with a bamboo backing.

And Bryce has not had backing overpower yew, because yew is so elastic.

Stiff hard woods just need to start off thinner back to front, and elastic woods can be a bit thicker.
« Last Edit: January 09, 2017, 05:44:19 pm by Springbuck »

Offline Ballasted_Bowyer

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Re: A question for Yew guys
« Reply #16 on: January 11, 2017, 12:12:44 am »
What is trapping?
Acts 10:12-13  "It contained all kinds of four-footed animals, as well as reptiles and birds. Then a voice told him, 'Get up, Peter. Kill and eat.'"

Offline Springbuck

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Re: A question for Yew guys
« Reply #17 on: January 21, 2017, 12:52:57 pm »
Sorry.  Trapping refers to removing wood from the front corners, creating a narrow front and a wider back, thus a TRAPEZOIDAL cross section.  Trapping is done to balance strong backs and medium or weaker bellies, or just to balance tension and compression.  Tough woods like elm, some maples, hickory, that are not super dense or super strong (or super elastic) in compression do really well to have either a crowned back as from a sapling, or trapped limbs so there is less back and more belly surface.  This helps avoid set and helps avoid more limb mass than needed.

With backings it serves the same function.  Bamboo is very tension strong (won't break) and tension resistant (won't stretch), which makes the belly wood really squish a bit more in compression.  So, while I may not trap a bulletwood or osage bow backed with bamboo, I would trap a bamboo-backed black locust, muilberry heartwood, or goncalo alves

Offline WillS

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Re: A question for Yew guys
« Reply #18 on: January 22, 2017, 07:33:53 am »
I have a secret plan to try Yew /Hazel... but don't tell anyone, I want to be the first to try it ::)
Del

It's already been done ;)