| View previous topic :: View next topic |
| Author |
Message |
jacobyfineviolins
Member
Joined: 04 Mar 2013
Posts: 55
Location: Omaha, NE
|
|
| Back to top |
|
 |
Michael Darnton
Moderator
Joined: 23 Mar 2007
Posts: 1347
Location: Chicago
|
 Posted: Tue Mar 12, 2013 7:31 am Post subject: |
 |
|
| R Mac wrote: | The result is a plate that is mathematically perfect on the outside, but just a bit wonky on the inside.
Have I got that? |
That's a pretty good summary, yes. There are a few other things I watch out for in grads--try to keep the right proportions in the right place in the back, more or less. Try not to go too thin in important places on the top, while maybe letting some others go, yes. But I use the tools the way I suppose "they" used them, in order to arrive at the same results "they" did.
_________________
new blog at my site! http://darntonviolins.com/blog
my work sites: http://darntonviolins.com and http://darntonhersh.com |
|
| Back to top |
|
|
actonern
Super Member
Joined: 15 Aug 2007
Posts: 444
|
| Posted: Tue Mar 12, 2013 8:28 am Post subject: |
|
|
"...Try not to go too thin in important places on the top..."
"Where might those areas be?" he asked, with averted gaze...
E |
|
| Back to top |
|
|
Chet Bishop
Super Member
Joined: 23 Mar 2007
Posts: 678
Location: Forest Grove, Oregon
|
| Posted: Tue Mar 12, 2013 9:15 am Post subject: |
|
|
| Michael Darnton wrote: | Some of us have speculated about it, but we don't really know. The resin molecule of spruce and fir trees has a helical spin to it, too. There's been discussion about that, whether it differs between continents, etc. No one cares enough to find out, I guess.
The stockade at Ft. Wilkins, in Michigan:
 |
Seems to me that this photo (the stockade) would be proof that it is NOT the rotation of the earth, or (maybe) even the wind, but simply a genetic predisposal to twist-- you have, side by side, examples with extreme twist, and with essentially none.
I have personally cut trees, side by side, one with a twist that will turn 90 degress in ten feet, and the other without. (I don't think I have seen one that twists the other direction, however, which could still be a genetic trait.)
I have only once or twice has a spruce top where the natural twist seemed to be the opposite direction, and that could have been simply the way it was cut.
_________________
Chet Bishop
https://bluefiddles.com
https://fivestringfiddles.com |
|
| Back to top |
|
|
Michael Darnton
Moderator
Joined: 23 Mar 2007
Posts: 1347
Location: Chicago
|
| Posted: Tue Mar 12, 2013 10:52 am Post subject: |
|
|
| actonern wrote: | "...Try not to go too thin in important places on the top..."
"Where might those areas be?" he asked, with averted gaze...
E |
Over the post, right in front of the end blocks, around the edges of the f-holes. Kind of the obvious spots.
_________________
new blog at my site! http://darntonviolins.com/blog
my work sites: http://darntonviolins.com and http://darntonhersh.com |
|
| Back to top |
|
|
R Mac
Member
Joined: 05 Mar 2013
Posts: 80
Location: Near Phily USA
|
| Posted: Tue Mar 12, 2013 10:56 am Post subject: |
|
|
| Michael Darnton wrote: | | But I use the tools the way I suppose "they" used them, in order to arrive at the same results "they" did. |
The logic of this is very compelling. Do you extend that principal to the entirety of the construction, or only to places where you think it matters?
Mac |
|
| Back to top |
|
|
Michael Darnton
Moderator
Joined: 23 Mar 2007
Posts: 1347
Location: Chicago
|
|
| Back to top |
|
|
actonern
Super Member
Joined: 15 Aug 2007
Posts: 444
|
| Posted: Tue Mar 12, 2013 11:10 am Post subject: |
|
|
Thanks again Michael!
Do you think it's helpful to leave that little area under the bottoms of the f holes that can be so "lively" a little stouter?
You know the area I mean? Where, for instance, internal dampers are often installed on cellos?
E |
|
| Back to top |
|
|
Michael Darnton
Moderator
Joined: 23 Mar 2007
Posts: 1347
Location: Chicago
|
|
| Back to top |
|
|
Jim Bress
Junior Member
Joined: 12 Mar 2013
Posts: 9
|
| Posted: Tue Mar 12, 2013 1:42 pm Post subject: |
|
|
| Michael Darnton wrote: | Some of us have speculated about it, but we don't really know. The resin molecule of spruce and fir trees has a helical spin to it, too. There's been discussion about that, whether it differs between continents, etc. No one cares enough to find out, I guess.
The stockade at Ft. Wilkins, in Michigan:
|
Hi, I just came out of lurking (and learning) to respond. I learn alot from you guys, so when I can actually contribute I will try to help.
Chet is correct that the twist growth pattern is genetic, but the expression of this trait can be influenced by the environment. Here is review on the function spiral growth.
Oops I don't know how to upload a PDF yet. Here's the url: http://link.springer.com/article/10.1007%2FBF00204333?LI=true#
Then click the "look inside" box to the right.
Some species such as Corylus avellana (corkscrew hazelnut) have been experimentally shown to carry heritable gentic trait for twisted growth pattern. I can dig up a citation if anyone is interested.
I've missed your posts Chet, glad I found you (and others) again.
Cheers,
Jim |
|
| Back to top |
|
|
Michael Darnton
Moderator
Joined: 23 Mar 2007
Posts: 1347
Location: Chicago
|
|
| Back to top |
|
|
ctviolin
Super Member
Joined: 07 May 2009
Posts: 961
Location: Roswell
|
| Posted: Tue Mar 12, 2013 2:03 pm Post subject: |
|
|
| Michael Darnton wrote: |
Keep your eyes open, and you'll see the wood always twists the same way. . . at least in the Northern Hermisphere. 
|
Would lead me to think that the twist is related to the spin of the planet... but then again, that would mean that the spin would be the same - no matter what hemisphere the wood came from, since the earth spins in only one direction.
And that (spin) direction wouldn't depend on (or change because of a) hemispherical location, right? Or would it?
Interesting.
_________________
Look,
Listen,
Learn.
Last edited by ctviolin on Tue Mar 12, 2013 3:03 pm; edited 1 time in total |
|
| Back to top |
|
|
Chet Bishop
Super Member
Joined: 23 Mar 2007
Posts: 678
Location: Forest Grove, Oregon
|
| Posted: Tue Mar 12, 2013 2:46 pm Post subject: |
|
|
| ctviolin wrote: | | Michael Darnton wrote: |
Keep your eyes open, and you'll see the wood always twists the same way. . . at least in the Northern Hermisphere.
|
Would lead me to think that the twist is related to the spin of the planet... but then again, that would mean that the spin would be the same - no matter what hemisphere the wood came from, since the earth spins in only one direction.
And that (spin) direction wouldn't depend on (or change because of a) hemispherical location, right? Interesting. |
Point of view matters-- a man who watches the sun, from noon to sundown in the Northern Hemisphere will observe the apparent movement from high point, shifting to his right, and moving toward the horizon...in the Southern Hemisphere, it would seem to move to his left, and down toward the horizon.
So a plant that follows the sun (think sunflowers, etc.) will move in a clockwise manner in the North, (from their own perspective) and counterclockwise in the South. Whether that has any effect on the grain in spruce trees is another matter.
Wood suppliers here have estimate that about 4% of spruce trees do NOT have the twist...that I should expect to find one in 25 that would be suitable for instrument,s on that basis alone, not counting other issues (knots, bug damage, etc.).
I have all the maple I need right now, but I would love to find a big log of Sitka spruce. I am getting old enough, however, that I am beginning to think that picking through the fruit of someone else's labor sounds like a better and better deal.
_________________
Chet Bishop
https://bluefiddles.com
https://fivestringfiddles.com |
|
| Back to top |
|
|
R Mac
Member
Joined: 05 Mar 2013
Posts: 80
Location: Near Phily USA
|
| Posted: Tue Mar 12, 2013 3:04 pm Post subject: |
|
|
| Jim Bress wrote: |
Chet is correct that the twist growth pattern is genetic, but the expression of this trait can be influenced by the environment. Here is review on the function spiral growth.
Oops I don't know how to upload a PDF yet. Here's the url: http://link.springer.com/article/10.1007%2FBF00204333?LI=true#
Then click the "look inside" box to the right.
|
Jim,
That article looks really good, from what I can see of it.
Do I understand that if you can figure out how to do it, you would load up the whole thing so we can read it? What would be great!
Mac |
|
| Back to top |
|
|
Jim Bress
Junior Member
Joined: 12 Mar 2013
Posts: 9
|
| Posted: Tue Mar 12, 2013 3:51 pm Post subject: |
|
|
| R Mac wrote: | | Jim Bress wrote: |
Chet is correct that the twist growth pattern is genetic, but the expression of this trait can be influenced by the environment. Here is review on the function spiral growth.
Oops I don't know how to upload a PDF yet. Here's the url: http://link.springer.com/article/10.1007%2FBF00204333?LI=true#
Then click the "look inside" box to the right.
|
Jim,
That article looks really good, from what I can see of it.
Do I understand that if you can figure out how to do it, you would load up the whole thing so we can read it? What would be great!
Mac |
Yup, I would glad to, but I still don't see a way of doing it. You could also open up "google scholar" and then search "Function of spiral grain in trees" and it will be the first link.
Jim |
|
| Back to top |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
