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  #31  
Old 10-09-2011, 07:16 PM
JCave JCave is offline
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Originally Posted by Mary View Post
Kurt discovered I was allergic to his Petosky stone guitar.
Mary -


Please excuse my absence from the loop. Would you please tell me more about a Petosky stone guitar? State rock (fossil) of Michigan. I've used them in jewelry but I'd like to see the guitar application.




Jerry
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  #32  
Old 10-09-2011, 08:41 PM
fulfillingsoul fulfillingsoul is offline
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Originally Posted by Tim McKnight View Post
Bruce,
I thickness each back to a desired stiffness and not to a given thickness dimension. I measure how much the top (and back) bow or "deflect" under a standard weight. This measured deflection of each piece of wood tells me exactly how stiff the top or back is. I keep running the top & back through my thickness sander, gradually removing a few thousandths of wood per pass and then repeating the deflection measurement until it bows or deflects a certain distance. This way all of my backs and tops are thicknessed to a desired stiffness regardless of the thickness. I have built with extremely stiff tops that measured -.080" and I have also used "floppy" tops that were +.140" thick yet both had the same stiffness measured on my deflection board. This just proves how much natural inherent variation there is in wood.

"Tim don't you ever get tired of sanding?" Yes, I do Bruce and I often ask myself why in the world do I sand the interior parts of the guitar that no one will likely ever see or touch. The only logical answer I can muster is "because its the way I am wired".

The two carbon tubes are braces that take the rotational torque load off of the neck block. As the strings exert pull on the neck the resulting force is trying to rotate the neck block and entire upper bout end of the guitar in an effort to make to collapse the top into the sound hole. This force will eventually allow guitars, without supports like these, to deform which results in a need for a neck reset. The carbon tubes transfer this rotational force to the waist which is the stiffest point on the guitar. It is highly unlikely that guitars with this truss brace design will ever need a neck reset. It makes the upper bout system extremely rigid without negatively influencing the movement of the soundboard.
Hi are the carbon tubes installed solely for structural reasons, any effect on tone at all?

Is it necessary because soundboards of guitars by custom luthiers are thinner or braced more lightly, compared to the usual factory production guitars? Thanks!
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  #33  
Old 10-09-2011, 08:48 PM
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Bruce, that rosette DID turn out wonderful. I like it, too! Nicely done McKnights!

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Originally Posted by JCave View Post
Mary -

Please excuse my absence from the loop. Would you please tell me more about a Petosky stone guitar? State rock (fossil) of Michigan. I've used them in jewelry but I'd like to see the guitar application.

Jerry
I was curious about that as well.


Bel isi,
-kyle
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  #34  
Old 10-10-2011, 07:00 AM
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Originally Posted by fulfillingsoul View Post
Hi are the carbon tubes installed solely for structural reasons, any effect on tone at all?

Is it necessary because soundboards of guitars by custom luthiers are thinner or braced more lightly, compared to the usual factory production guitars? Thanks!
The carbon tubes are installed to structurally reinforce the neck block area but more importantly to eliminate or re-direct the rotational torque of the neck block. There could be a tonal gain but I have no way to validate that claim. We know that there is a downward force applied to the fingerboard extension upon the sound board above the sound hole of most guitars. The carbon tubes would resist that downward force so it stands to reason the sound board could be freer to vibrate in that area.

Years ago I would have argued the point that the sound board is pretty dead above the sound hole but my view has certainly changed. When I place a ToneRite on my guitars, during the initial settling in period and prior to the final set ups, I run my finger tips all over the top, back, sides and neck to get some tactile feedback about how active those parts are vibrating. Since implementing the carbon tubes into my build design the area above the sound hole feels a LOT more active than my guitars without them. I think there is a lot of high frequency response coming from that area of the top. Therefore its reasonable to assume that this structural design element could reinforce treble response in my guitars.
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  #35  
Old 10-10-2011, 07:08 AM
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Quote:
Originally Posted by JCave View Post
Mary -


Please excuse my absence from the loop. Would you please tell me more about a Petosky stone guitar? State rock (fossil) of Michigan. I've used them in jewelry but I'd like to see the guitar application.
Jerry
Hi Jerry,
Kurt provided the stone for us and we inlayed it into his Peg head and fret board. You can see a picture of the peg head inlay here - http://mcknightguitars.com/inlays.html

The Petosky stone was very fragile to work with but the end result was spectacular. I really liked how the stone "popped" under the finish on the peg head. The fingerboard inlay is less pronounced since there is no finish on it.
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  #36  
Old 10-10-2011, 07:11 AM
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I am surprised no one mentioned the green stuff hanging in the back ground. Our daughter said it looks like we are drying something illegal but rest assured it is just our fall harvest of spearmint that we mix with our green tea. Its really quite refreshing.
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  #37  
Old 10-10-2011, 08:03 AM
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Steve Kinnaird Steve Kinnaird is offline
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Tim, no one smiles that much gluing bindings together.
Those green things are suspect....

BTW, it's looking great. Beautiful set of Ziricote!

Steve
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  #38  
Old 10-10-2011, 09:03 AM
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Originally Posted by Steve Kinnaird View Post
Tim, no one smiles that much gluing bindings together.
Those green things are suspect....

BTW, it's looking great. Beautiful set of Ziricote!

Steve
Have you found an easier way to glue purflings to bindings Steve? Its one of those pesky little jobs that I like to put off. Mary was gracious enough to lend a smiling hand even though she was touching coco!

I wish I had a truckload of that Zircote + a bank account large enough to afford to buy a truck load of it Its getting more difficult to find quality sets like these.
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  #39  
Old 10-10-2011, 09:38 AM
fulfillingsoul fulfillingsoul is offline
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Thanks Tim! I am so enlightened.

You reckon this will get more commonly used amongst luthiers?
I think I have seen this as Kent Chasson's methodology on his website?

Quote:
Originally Posted by Tim McKnight View Post
The carbon tubes are installed to structurally reinforce the neck block area but more importantly to eliminate or re-direct the rotational torque of the neck block. There could be a tonal gain but I have no way to validate that claim. We know that there is a downward force applied to the fingerboard extension upon the sound board above the sound hole of most guitars. The carbon tubes would resist that downward force so it stands to reason the sound board could be freer to vibrate in that area.

Years ago I would have argued the point that the sound board is pretty dead above the sound hole but my view has certainly changed. When I place a ToneRite on my guitars, during the initial settling in period and prior to the final set ups, I run my finger tips all over the top, back, sides and neck to get some tactile feedback about how active those parts are vibrating. Since implementing the carbon tubes into my build design the area above the sound hole feels a LOT more active than my guitars without them. I think there is a lot of high frequency response coming from that area of the top. Therefore its reasonable to assume that this structural design element could reinforce treble response in my guitars.

Last edited by fulfillingsoul; 10-10-2011 at 10:00 AM.
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  #40  
Old 10-10-2011, 10:18 AM
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Originally Posted by fulfillingsoul View Post
Thanks Tim! I am so enlightened.

You reckon this will get more commonly used amongst luthiers?
I think I have seen this as Kent Chasson's methodology on his website?
Its hard to say. Its a lot more work (read labor hours) plus it adds material cost so it may not be for every one. Its likely it will never make it into mass production for those two reasons alone. I only make changes in my build process if there is a benefit to tone, play-ability or structure and pretty much absorb the costs, thus far... I can see the benefit of not needing a neck reset though none of my guitars have required a neck reset yet in my 20 years of building.
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  #41  
Old 10-11-2011, 08:00 AM
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Most people don't see me handle their parts and pieces. I prefer to stay behind the camera and post all the looks Tim gives.

He picked up the camera and told me to smile. I tried to give a "serious Tim McKnight look, " but I just couldn't muster it up. I laugh too easily.
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  #42  
Old 10-11-2011, 08:26 AM
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Quote:
Originally Posted by JCave View Post
Mary -
Please excuse my absence from the loop. Would you please tell me more about a Petosky stone guitar? State rock (fossil) of Michigan. I've used them in jewelry but I'd like to see the guitar application. Jerry
Jerry,

I'm glad you asked that question! We had someone from Michigan cut the stone to shape. Kurt wanted it in the shape of the perfect leaf that he found on the ground of his parents property. It adds to the sentimental side of the guitar. His peg head can be seen on our MYSPACE site (below). It made a beautiful guitar center piece. I requested that we add a small oval the 12th fret. Kurt really liked the outcome.

http://www.myspace.com/my/photos/alb...ustom/list?u=1 (double click the picture to enlarge it.)

I also found this thread that might tell you a little about the guitar

http://www.acousticguitarforum.com/f...cknight+guitar
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Last edited by Mary; 10-11-2011 at 09:00 AM. Reason: Smile = small oval. (my bad)
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  #43  
Old 10-11-2011, 08:54 AM
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Quote:
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...I laugh too easily.
I respectfully disagree. Your joy in life is wonderfully contagious!

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  #44  
Old 10-11-2011, 09:00 AM
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Cotten (Thank you)
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  #45  
Old 10-11-2011, 12:51 PM
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Steve Kinnaird Steve Kinnaird is offline
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Quote:
Originally Posted by Tim McKnight View Post
Have you found an easier way to glue purflings to bindings Steve? Its one of those pesky little jobs that I like to put off. Mary was gracious enough to lend a smiling hand even though she was touching coco!
No I haven't, unless you factor in Ryan doing the job, and then it's a breeze.
(for me...)

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Originally Posted by Tim McKnight View Post
I wish I had a truckload of that Zircote + a bank account large enough to afford to buy a truck load of it Its getting more difficult to find quality sets like these.
Yup... we're wishing the same things amigo.

Steve
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