CA gluing Grand Pinblocks....My take on it/ Richard Brekne

[Farrell]

Yeah, we are closer. My terminology may be less than ideal. I think the proper term to use rather than shear force is shear stress. My terms are coming largely from my graduate studies in structural geology (a few years back now!) - but forces are forces, and stresses are stresses. If it is not compression, and it is not tension, and you are talking about two parallel planes of reletive motion (or force), then you have a shear stress.

That is, of course, if I remember correctly!  ;-)

Terry Farrell
  
----- Original Message ----- 
From: "Richard Brekne" <Richard.Brekne@grieg.uib.no>
To: <pianotech@ptg.org>
Sent: Wednesday, July 31, 2002 9:01 PM
Subject: Re: CA gluing Grand Pinblocks....My take on it/ Richard Brekne


> Terry Farrell wrote:
> > 
> > Boy, a picture would be worth a thousand words. I am just
> > talking about a pin in a hole in maple. Push it to one
> > side. You will have tensional forces between the pin and
> > wood on the side of the pin where the force was applied.
> > You will have compression forces 180 degrees to the
> > tension forces. And you will have shear forces between the
> > pin and the wood along a plane parallel to the pushing
> > force (90 degrees from the compression and tension
> > forces).
> > 
> 
> 
> Ok.. I can buy this.... I think. Tho I would feel more
> comfortable with your last sentence if it read :
> 
> "And you will have shear forces applied TO the pin by the
> string and bridge along a plane parallel to the pushing
> force"
> 
> Perhaps this makes more clear where I am getting hung up on
> what you, Keith, and Joe seem to be saying. I dont see any
> shear force being applied TO the bridge..., only from it TO
> the pin, and only at the exact point that is on the plane
> between the bridge surface and the string. 
> 
> When you say there are shear forces BETWEEN the pin and the
> maple, I start looking for some sliding motion possibilites
> between these two.... and I dont see what the string pushing
> on the pin can do to cause any.
> 
> Are we any closer ??
> 
> Cheers
> RicB