Rib grain orientation

[Farrell]

Hi Ron. You mentioned that you have a "large slab of Sitka" for cutting ribs from. I'm currently in the process of searching for some rough cut Sitka lumber. I can get it from about 30mm thick to any thickness I want, kiln dried or green. Where are you getting your from? How are you drying it, or how was it dried when you got it? How thick do you get it? I've been told that you can run into a fair bit of checking if you cut it too thick. What is your experience? Have you ever air dried it from green? Thanks.

Terry Farrell
  
----- Original Message ----- 
From: "Ron Overs" <sec@overspianos.com.au>
To: "Pianotech" <pianotech@ptg.org>
Sent: Sunday, December 08, 2002 3:43 AM
Subject: Re: Rib grain orientation


> At 11:52 PM -0500 7/12/02, Erwinspiano@aol.com wrote:
> 
> >                 Honestly I wonder if it matters. I cut up some tight 
> >grain& dense old sugar pine stock from material gutted from a old 
> >pipe organ. Some of the pieces took on a beautiful tight arc 
> >appropriate for some tight radius treble ribs.
> 
> Sure, but I was wondering if we shouldn't be choosing to cut it with 
> the rays vertical, if there is a choice, to gain the benefit of the 
> slightly higher modulus of elasticity along the line of the ray.
> 
> >      If there was a slight stiffness difference it could be made up 
> >in rib thickness.
> 
> True, but ideally aren't we trying to achieve the highest panel 
> stiffness with the least weight?
> 
> >No big deal. Ask some one in our engineering dept. if the wood 
> >strength formulas change for this slight change in orientation. 
> >(that would be you).
> 
> Ron N's post confirmed that there is a minor though measurable 
> improvement in strength along the line of the ray.
> 
> >. . Why would it be benificial to change the grain orientation to 
> >have the ray run the other way.I don't follow this.
> 
> 
> I put forward the question since I have a large slab of Sitka from 
> which I will be cutting out the rib stock for piano 4. The board is 
> of such a size that I have a choice of grain orientation. The 
> question was intended to see if any others might be sharing my views 
> on this matter.
> 
> I agree its a very small point, but sometimes its the minutiae we 
> concern ourselves with. Following on from Ron N's post where he 
> discussed the orientation of the rays in hammer shanks, he was saying 
> that most makers don't seem to regard it as important. Indeed, I have 
> tested hammer shanks for stiffness with and perpendicular to the ray 
> and its only just measurable using a dial guage.
> 
> Ron O.
> -- 
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> 
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> 
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