From: Julio MacWilliams <juliom@cisco.com>
Message-Id: <199610110051.RAA13240@monarch.cisco.com>
Subject: Re: Fwd: Stiffness/strength of wood.
To: baidarka@lists.intelenet.net
Date: Thu, 10 Oct 1996 17:51:55 -0700 (PDT)
In-Reply-To: <199610110017.RAA22161@dfw-ix8.ix.netcom.com> from "Robin McDaniel" at Oct 10, 96 05:17:48 pm
> However, if the bundle of small twigs I mentioned in a previous
> message are well fastened they should be as stiff as a single piece of
> the same thickness as the bundle. Well, almost; some stiffness would
> be lost due to the space between the round edges of the small twigs.
> So, if someone wants to use smaller ribs, they should combine them into
> a few ribs widely spaced rather than many ribs closely spaced.
>
> -- Andy Wones
>
That is not exactly right. Both stiffness and strenght depend on the outer
layer of wood. In fact, a rib could be hollow, and be equally strong.
If you tied the two ribs one on top of each other, you might end up with
a stronger rib. If you put them side by side, you add no significant
stiffness. If there was a way to wrap around a rib over another, you
would gain strength and stiffness, but then you could throw away the
inner one since it is doing almost nothing.
Try this: bend a copper wire. Now bend a copper tube like those used
for hot water plumbing. Then bend several tubes with different diameters.
See the difference?
Outside of theory, why do you not try it? Put two ribs together and bend
them. Then look for a piece of wood with double diameter.
If willow is hard to find, get white oak strips and steam bend them
(I still prefer to soak them in cold water for 5 days and pour boiling
water as I bend).
have fun
- Julio