CF rods and computing neck stiffness

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Dominic
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Re: CF rods and computing neck stiffness

Post by Dominic » Thu Apr 11, 2013 1:07 am

Michael Thames wrote:
Déjà vu. This is obviously just a math problem that can be solved with the right values for the actual materials used and some work in excel. Some homework for you Michael?
Dominic, as you can see I've been doing some homework, and is why I posted these wrong specs here, that everyone used as fact.
Hard science has proved many intuitive ideas wrong over time. Its what keeps things interesting moving forward.
Yes, and Einstein once said, "All great achievements of science must start from intuitive knowledge. I believe in intuition and inspiration.... At times I feel certain I am right while not knowing the reason."

My friend, I think it's a big mistake to build guitars along the lines of pure science.
Interesting that you think my guitar building methods are a mistake or that I build guitars based on pure science. You don't know me and have never seen my guitars or watched me make one. Yet you feel qualified to offer this critique.

What I am hearing is mostly polemics dressed up as informed debate. One only has to read the classical forum to see it is perhaps the ugliest online lutherie community out there. I remember the snake-oil-salesman slurs as some of the more polite comments made and decided there was nothing there of interest to me. Fortunately I think most of us here at the ANZLF are not interested in having those kind of debates or the people that raise them.

So, my point is and remains that many/most hunches in guitar building can be tested using recognised scientific methods so why not put them to the test? Put your numbers up so they can be run through Hurd's equations and we will know for a fact, no intuition required, what the impact of cf is.

Cheers
Dom
You can bomb the world to pieces,
but you can't bomb the world to peace!

Michael Thames

Re: CF rods and computing neck stiffness

Post by Michael Thames » Thu Apr 11, 2013 6:17 am

Dominic, I didn't mean to critique your work or your approach to guitar making. I did try and find a link to your guitars in your profile, but couldn't find a website link or anything. Please, if you don't mind link up your website so at least I can take a look..... thanks!

Michael Thames

Re: CF rods and computing neck stiffness

Post by Michael Thames » Thu Apr 11, 2013 7:06 am

So, my point is and remains that many/most hunches in guitar building can be tested using recognised scientific methods so why not put them to the test? Put your numbers up so they can be run through Hurd's equations and we will know for a fact, no intuition required, what the impact of cf is.
I don't need to use Hurd's program, Jim has written his own and will publish it this weekend....... if you actually have been following this thread you might have known this.
What I am hearing is mostly polemics dressed up as informed debate. One only has to read the classical forum to see it is perhaps the ugliest online lutherie community out there. I remember the snake-oil-salesman slurs as some of the more polite comments made and decided there was nothing there of interest to me. Fortunately I think most of us here at the ANZLF are not interested in having those kind of debates or the people that raise them.
Well at least you got the informed debate part right! The rebuttal of Trevor Gore's publications and writings that contain false information is open to scientific critique is it not? I have shown without a doubt that the information Trevor used in his finding were WAY off. This you call polemics, you are the only one around here who is turning this into a personal attack and ugliness, I have not personally attacked anyones character only their scientific data.

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Trevor Gore
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Re: CF rods and computing neck stiffness

Post by Trevor Gore » Thu Apr 11, 2013 9:35 am

Michael Thames wrote: The rebuttal of Trevor Gore's publications and writings that contain false information is open to scientific critique is it not? I have shown without a doubt that the information Trevor used in his finding were WAY off.
No you haven't...yet! All you've done is broadcast some unsubstantiated numbers and on that basis accused me of publishing false information. Hurd's figure for the modulus of the CF composite that he was analysing is different from yours, but Hurd's figure seems to be within the range of composites available, and is related (amongst other things) to the packing density of the CF in the epoxy, which is a manufacturer's choice. Until Jim Martin publishes his analysis and demonstrates where Hurd erred, all we have is another unsubstantiated rant.

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Re: CF rods and computing neck stiffness

Post by jeffhigh » Thu Apr 11, 2013 9:59 am

One reason the discussions elsewhere fell apart was that people where talking about different scenarios for CF reinforcement
The Stewmac product promoted is a 5mm x 9.5mm bar with instructions to place it flush with the neck surface.

That is a pretty common scenario for people using it "for insurance"

Michael here has talked about using 5mmx14mm, 10mmx 14mm and 6.34X13mm and also placing it further to the back of the neck.

I just reran the calcs in the spreadsheet using a higher modulus for the CF (18) and for a 5x 9.5 bar and a 6.34x13 both set flush

For the Honduras mahogany listed this gave me about 11%stiffness increase for the small bar and 35% for the larger
For Cedro the increase was greater 15% and 54%

Placing the bar further back in the neck even by a few mm would probable produce a much greater increase

It would be good if we could see the truth in both positions-
- the standard recommended bar does little
-increases in size and modifications in position can produce large increases in stiffness

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Trevor Gore
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Re: CF rods and computing neck stiffness

Post by Trevor Gore » Thu Apr 11, 2013 11:02 am

I found a piece of off-cut of Stewmac CF rod, 1/8" x 3/8" (Stewmac don't seem to list a 5mm x 9.5mm, which would be 3/16" x 3/8"). I measured its Young's modulus at 105.8 GPa (or 15.3 Million psi). Using Hurd's spreadsheet (which, currently, I have no reason to doubt, but I haven't done a line by line check - imperial units are such a pain...) with the CF used in the usual way with twin bars (example #2) in a typical mahog/ebony neck config I got ~13% increase in stiffness.

I'd still use an adjustable truss rod in preference.
jeffhigh wrote:Placing the bar further back in the neck even by a few mm would probable produce a much greater increase

It would be good if we could see the truth in both positions-
- the standard recommended bar does little
-increases in size and modifications in position can produce large increases in stiffness
I wouldn't argue with that.

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Re: CF rods and computing neck stiffness

Post by jeffhigh » Thu Apr 11, 2013 11:17 am

Yes I got confused on the width should be 1/8 wide by 3/8 which will do bugger all in a single central application.

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Re: CF rods and computing neck stiffness

Post by needsmorecowbel » Thu Apr 11, 2013 12:35 pm

I too haven't read Trevor's books, but, if one were sitting on the coffee table while I was at the dentist office I might give it a look...... that of course depends on if there were a Playboy next to it.
Comparing two 200 + page hardback books that I can only assume took a lot of time & research to produce to some glossy semi pornographic magazine (In a Dentist's Office) is a bit of a slap in the face, don't you think?

Even if it just is a harmless analogy you'd have been much better off waiting for your friend to publish his findings then presenting his findings in a polite manner or a discussion and avoiding all these little personal digs without anything much except: "my mate knows best he's a brillian physicist".

Or Better yet get your brilliant physicist to sign up and create a positive discussion on this forum rather than a "debate". Debates are so agressive and formal and this isn't really a very formal place (some of the members might even be in their undies). I can't add or subract anything from the science of this "debate" but I could discuss ettiquette and propriety at length with you if you like or Jane Austen or Badgers or some equally insignifigant topic.

It appears to be a worrying trend on forums where intelligent/ schooled people can't just express a scientific idea without inadvertedly offending several people. At no point in this reply have I Insulted you, Michael, merely critiqued your way of "debating". Call this rebuttal if you prefer but at no point have you presented a cohesive argument with scientific evidence. The only evidence I have seen to back up your argument is that you have made 850 classical guitars and two steel strings. But any credibility you have gained from this statement is immediately undermined by the personal digs you dish out in your "scientific debate" towards Dom and Trevor. Present the cold hard science without all the poppycock please.

I don't have a website and haven't even built an acoustic yet but I can form a cohesive argument without insulting someone. Next time you post a "debate" please try to avoid using empty rhetoric/ personal insults and you yourself could develop a solid argument from which a positive discussion may blossom. I look forward to seeing how the science stands up.

[INSERT{"Sting In The Tail here"}INSERT]

NEXT SPEAKER for the Negative...In the Debate "CF rods and computing neck stiffness"

Stu

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Re: CF rods and computing neck stiffness

Post by 68matts » Thu Apr 11, 2013 12:55 pm

(some of the members might even be in their undies)
Undies!
Since I started building guitars I can't afford luxuries like undies anymore :roll:

Well said BTW Stu.
Matt

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Trevor Gore
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Re: CF rods and computing neck stiffness

Post by Trevor Gore » Thu Apr 11, 2013 1:32 pm

needsmorecowbel wrote:Comparing two 200 + page hardback books...
~350 and ~450; or about 25 cents a page, though I do prefer to sell them bundled... :D

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Re: CF rods and computing neck stiffness

Post by needsmorecowbel » Thu Apr 11, 2013 1:52 pm

Sorry Trevor It was a bad estimate. My excuse is that i've damaged the tendon/ soft tissue around my thumb and I didn't want to risk lifting such a weighty object. Just kidding my injury is not that severe...indoor cricket balls can do some damage.

Stu

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Re: CF rods and computing neck stiffness

Post by Trevor Gore » Thu Apr 11, 2013 3:37 pm

:lol: No worries, Stu.
needsmorecowbel wrote:My excuse is that i've damaged the tendon/ soft tissue around my thumb...
I know your problem! Guess how I did mine... yes, shifting books! :lol:

Michael Thames

Re: CF rods and computing neck stiffness

Post by Michael Thames » Thu Apr 11, 2013 4:01 pm

trevtheshed wrote:
Michael Thames wrote: The rebuttal of Trevor Gore's publications and writings that contain false information is open to scientific critique is it not? I have shown without a doubt that the information Trevor used in his finding were WAY off.
No you haven't...yet! All you've done is broadcast some unsubstantiated numbers and on that basis accused me of publishing false information. Hurd's figure for the modulus of the CF composite that he was analysing is different from yours, but Hurd's figure seems to be within the range of composites available, and is related (amongst other things) to the packing density of the CF in the epoxy, which is a manufacturer's choice. Until Jim Martin publishes his analysis and demonstrates where Hurd erred, all we have is another unsubstantiated rant.


What are you talking about......unsubstantiated numbers like the correct rating for CF used for decades for truss rods...... you mean those false numbers? Then I kindly point out to you ebony doesn't float? You mean that kinda stuff?

Using this vague "bullshit" (can I say that here?) of different ratings of manufactures, is a smoke and mirrors show. Manufactures of CF must comply with certain standards and ratings in order not to be sued. The standard stuff EVERYONE gets when they order CF rods from just about every different manufacture on the planet who supplies this stuff is 19.6 mpsi.

I had dinner with Jim Martin tonight and he told me he was on the phone for an hour with the engineer at Dragon plate...... the guy who actually makes the stuff to verify the modulus of the CF used for truss rods just to be certain of the facts before he presented his findings. Perhaps Hurd could have taken the time to properly investigate these facts, or at the very least, you could have done it before you started using his data to publish your theories.
http://dragonplate.com/default.asp?gcli ... MgodAXsAJA

So if you are saying that Hurd used a modulus for CF that is for unidirectional sheets, and thinks that everyone uses "sheets" for truss rods, then I have to agree with you, because 10,000,000 YM happens to be the rating of unidirectional CF sheets, and NOT some under rated over epoxy impregnated lesser quality CF.

Michael Thames

Re: CF rods and computing neck stiffness

Post by Michael Thames » Thu Apr 11, 2013 4:10 pm

needsmorecowbel wrote:
I too haven't read Trevor's books, but, if one were sitting on the coffee table while I was at the dentist office I might give it a look...... that of course depends on if there were a Playboy next to it.
Comparing two 200 + page hardback books that I can only assume took a lot of time & research to produce to some glossy semi pornographic magazine (In a Dentist's Office) is a bit of a slap in the face, don't you think?

Even if it just is a harmless analogy you'd have been much better off waiting for your friend to publish his findings then presenting his findings in a polite manner or a discussion and avoiding all these little personal digs without anything much except: "my mate knows best he's a brillian physicist".

Or Better yet get your brilliant physicist to sign up and create a positive discussion on this forum rather than a "debate". Debates are so agressive and formal and this isn't really a very formal place (some of the members might even be in their undies). I can't add or subract anything from the science of this "debate" but I could discuss ettiquette and propriety at length with you if you like or Jane Austen or Badgers or some equally insignifigant topic.

It appears to be a worrying trend on forums where intelligent/ schooled people can't just express a scientific idea without inadvertedly offending several people. At no point in this reply have I Insulted you, Michael, merely critiqued your way of "debating". Call this rebuttal if you prefer but at no point have you presented a cohesive argument with scientific evidence. The only evidence I have seen to back up your argument is that you have made 850 classical guitars and two steel strings. But any credibility you have gained from this statement is immediately undermined by the personal digs you dish out in your "scientific debate" towards Dom and Trevor. Present the cold hard science without all the poppycock please.

I don't have a website and haven't even built an acoustic yet but I can form a cohesive argument without insulting someone. Next time you post a "debate" please try to avoid using empty rhetoric/ personal insults and you yourself could develop a solid argument from which a positive discussion may blossom. I look forward to seeing how the science stands up.

[INSERT{"Sting In The Tail here"}INSERT]

NEXT SPEAKER for the Negative...In the Debate "CF rods and computing neck stiffness"

Stu
I beg to differ, I supplied the correct Youngs Modulus for carbon fiber, and pointed out ebony doesn't float. Unless you can add to the discussion please kindly withhold the cheerleading for your favorite team.

Michael Thames

Re: CF rods and computing neck stiffness

Post by Michael Thames » Thu Apr 11, 2013 4:28 pm

I found a piece of off-cut of Stewmac CF rod, 1/8" x 3/8" (Stewmac don't seem to list a 5mm x 9.5mm, which would be 3/16" x 3/8"). I measured its Young's modulus at 105.8 GPa (or 15.3 Million psi). Using Hurd's spreadsheet (which, currently, I have no reason to doubt, but I haven't done a line by line check - imperial units are such a pain...) with the CF used in the usual way with twin bars (example #2) in a typical mahog/ebony neck config I got ~13% increase in stiffness.
We are supposed to believe your 15.3 mpsi over the engineer who actually makes the stuff at 19.6. Trevor, why don't you get with the times?

One positive trend is a steady up ward momentum in your specs. We'll see just how far they elevate when Jim presents his findings.

BTW, here are Jim's specs.

1) Cedro/ebony 1
2) Cedro/ebony/CF 1.92
3)Cedro/ebony/HM CF 2.09
4)Mahogany/ebony 1.40
5)mahogany/ebony/CF 2.14
6)mahogany/ebony/ HM CF 2.30

Michael Thames

Re: CF rods and computing neck stiffness

Post by Michael Thames » Thu Apr 11, 2013 4:37 pm

Comparing two 200 + page hardback books that I can only assume took a lot of time & research to produce to some glossy semi pornographic magazine (In a Dentist's Office) is a bit of a slap in the face, don't you think?
I wasn't condemning Trevor's book, I'm sure it has a lot of useful information in there, and I'll take your word for it about the guitar porn, I'm a sucker for that stuff. I just hope that the info in there is better researched than the stuff he puts up on guitar blogs, and articles he writes for the Guild of American Luthiers.

BTW, I'm going to write a book too, it will be about 5 pages long with lots of guitar porn, for those easily seduced.

Michael Thames

Re: CF rods and computing neck stiffness

Post by Michael Thames » Thu Apr 11, 2013 4:46 pm

One reason the discussions elsewhere fell apart was that people where talking about different scenarios for CF reinforcement
The Stewmac product promoted is a 5mm x 9.5mm bar with instructions to place it flush with the neck surface.

That is a pretty common scenario for people using it "for insurance"

Michael here has talked about using 5mmx14mm, 10mmx 14mm and 6.34X13mm and also placing it further to the back of the neck.

I just reran the calcs in the spreadsheet using a higher modulus for the CF (18) and for a 5x 9.5 bar and a 6.34x13 both set flush

For the Honduras mahogany listed this gave me about 11%stiffness increase for the small bar and 35% for the larger
For Cedro the increase was greater 15% and 54%

Placing the bar further back in the neck even by a few mm would probable produce a much greater increase

It would be good if we could see the truth in both positions-
Jeff, yes these seem to be a more realistic set of numbers thanks for running these! They still fall short of Jim's specs for whatever reason which I don't know. I think Jim has some other perimeters to add perhaps, maybe something not covered in Hurd's program.

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Re: CF rods and computing neck stiffness

Post by jeffhigh » Thu Apr 11, 2013 5:01 pm

What Bar size have you used?
Where is it located?
What neck width have you used ( I used 2.25" as typical of the middle of the fretboard)

Michael Thames

Re: CF rods and computing neck stiffness

Post by Michael Thames » Thu Apr 11, 2013 5:07 pm

Or Better yet get your brilliant physicist to sign up and create a positive discussion on this forum rather than a "debate". Debates are so agressive and formal and this isn't really a very formal place (some of the members might even be in their undies). I can't add or subract anything from the science of this "debate" but I could discuss ettiquette and propriety at length with you if you like or Jane Austen or Badgers or some equally insignifigant topic.
Yes, I've tried to get Jim signed up here believe me, but Jim debates and corrects others faulty science all day long, and quite frankly has no interest in debating people about this. He does have a healthy appetite for truth, and efficient science...... it's his passion. He told me he will present his findings and that's it.

Jim hasn't read a word of this, even though tonight I had my iPhone with me and tried to show him this thread, he had zero interest in it. Sorry but I tried.

Michael Thames

Re: CF rods and computing neck stiffness

Post by Michael Thames » Thu Apr 11, 2013 5:28 pm

jeffhigh wrote:What Bar size have you used?
Where is it located?
What neck width have you used ( I used 2.25" as typical of the middle of the fretboard)
Oh Man, I'm laying in bed now, and the neck dimensions are in the other room....... if I get up I'll wake up my wife and that would not be good.

Jim did write them down on the paper with those specs, I forgot to post those sorry, I'll do it tomorrow.

I believe the bar size was 5 X 13 mm which are what I have, I actually had cut them down to 13mm because they were much thicker. Can't remember where I bought them, I think if memory serves it was Dragon plate.

I put them as deep as I can, my necks are 22 mm or sometimes 21.5 under the 1st fret, and 24 or 23.5 at the 9th fret. I leave a couple mm's for safety so I don't go through the neck with the rod.

The width dimensions I gave Jim were 52 mm at the nut, tapering to 63 at the 12th fret, and a consistent 23 mm's total thickness. He noted the taper in the neck and rounded it off to 23mm's

Jim did mention like you did that setting them as deep as possible makes a huge difference. If I know Jim, he'll provide those specs too. Now if we add two of these bars at the same place and dimensions imagine how high the stiffness goes. For me it's no more trouble insetting two bars than it is just one, just a couple more runs on the table saw, it's just a little more expensive.

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Re: CF rods and computing neck stiffness

Post by nnickusa » Thu Apr 11, 2013 5:40 pm

Michael, mate. Your guitars are really nice. Your questioning the veracity of any published statements is accepted. BUT, you rock up here spoiling for a fight. The so-far mythical Jim Martin hasn't andor won't make an appearance to substantiate your comments with the proper math.

As stated, I haven't read Trevor's books, but plenty have, not only on ANZLF, and they are regarded as the next best thing, from what I've seen written about them.

If I was you, I'd fuck off if all you want is a fight over one paragraph out of 800 or so pages, or else, show where, why, and how exactly Trevor is wrong. Mate, this kind of discussion and attack is better suited to places like the gear page, where crappy name-calling and vague assertions don't seem to be out of the ordinary.

Michael, I looked at your work, and would like to see more, but this forum has a bit more decorum than you are, at present, showing.......

I'd suggest you come back here with a grown up attitude and a grown up sense of humour. State your case clearly and concisely, and you'd likely foment a rational and logical discussion of your position.

In the event that the elusive Mr. Martin finishes his analysis, I'm sure that all here would be interested in seeing it......

Seriously, mate, this forum isn't a hate-mongering place. It's full of really nice, helpful people you mightn't meet elsewhere. Treat it as such....

I'm done with this thread
I wish I was half the man my dog thinks I am....

Cheers,
Nick

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Michael Thames

Re: CF rods and computing neck stiffness

Post by Michael Thames » Thu Apr 11, 2013 5:51 pm

nnickusa wrote:Michael, mate. Your guitars are really nice. Your questioning the veracity of any published statements is accepted. BUT, you rock up here spoiling for a fight. The so-far mythical Jim Martin hasn't andor won't make an appearance to substantiate your comments with the proper math.

As stated, I haven't read Trevor's books, but plenty have, not only on ANZLF, and they are regarded as the next best thing, from what I've seen written about them.

If I was you, I'd fuck off if all you want is a fight over one paragraph out of 800 or so pages, or else, show where, why, and how exactly Trevor is wrong. Mate, this kind of discussion and attack is better suited to places like the gear page, where crappy name-calling and vague assertions don't seem to be out of the ordinary.

Michael, I looked at your work, and would like to see more, but this forum has a bit more decorum than you are, at present, showing.......

I'd suggest you come back here with a grown up attitude and a grown up sense of humour. State your case clearly and concisely, and you'd likely foment a rational and logical discussion of your position.

In the event that the elusive Mr. Martin finishes his analysis, I'm sure that all here would be interested in seeing it......

Seriously, mate, this forum isn't a hate-mongering place. It's full of really nice, helpful people you mightn't meet elsewhere. Treat it as such....

I'm done with this thread
Nick have you been drinking mate? This makes two nasty little posts by you, you sound like an angry drunk. Sober up lets talk tomorrow.

Michael Thames

Re: CF rods and computing neck stiffness

Post by Michael Thames » Thu Apr 11, 2013 6:01 pm

The so-far mythical Jim Martin hasn't andor won't make an appearance to substantiate your comments with the proper math.
Nick, like I've been saying all along, Jim will publish his finding this weekend, he wants to get everything right before his debut. He doesn't want to publish bad specs like Hurd, and Trevor Gore, then have to clean up his mess, and do damage control, Jim is not that kind of scientist...... he gets things right the first time around. Nick you can wait another day or two for good sound science can't you?

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Re: CF rods and computing neck stiffness

Post by Trevor Gore » Thu Apr 11, 2013 6:16 pm

Michael Thames wrote: What are you talking about......unsubstantiated numbers like the correct rating for CF used for decades for truss rods...... you mean those false numbers? Then I kindly point out to you ebony doesn't float? You mean that kinda stuff?
Well, the ebony density doesn't come into this calculation, which you've already been told. As for the CF modulus, like any other manufactured product it's subject to variation in both the design of the composite (intentional) and the variation in the process (unintentional). When you can measure it, why not? Then you know what you've actually got. Even if you use 20Mpsi for the CF modulus, and poke that into Hurd's program, you still only get a ~16% increase in stiffness for a standard config neck.

But, what I was really talking about was this:
Michael Thames wrote:OK here are the preliminary findings, these are computed for a cedro neck depth of 23 mm total...... combining a 6mm ebony fingerboard, a 17 mm cedro neck contoured to shape, with a CF rod 13 X 6.35 mm low modulus (19.6 mpsi) it will increase the neck stiffness by 92%. Introducing a high modulus CF rod (24.6 mpsi) same dimensions will increase the stiffness by 109%.
which you've added to with this:
Michael Thames wrote:BTW, here are Jim's specs.

1) Cedro/ebony 1
2) Cedro/ebony/CF 1.92
3)Cedro/ebony/HM CF 2.09
4)Mahogany/ebony 1.40
5)mahogany/ebony/CF 2.14
6)mahogany/ebony/ HM CF 2.30
Until we see how Jim has calculated these, just quoting numbers means nothing. They're just unsubstantiated numbers.

Hurd's analysis and program have been published and available since 2004, if not before, and I'm still waiting for someone to prove it wrong. You put numbers in, you get answers out and for the standard config the answer is the same whatever modulus number you use for the CF composite, namely, it makes barely any difference, because the standard config, using Stewmac CF, has the CF pretty much on the neutral axis. Put the numbers in and see for yourself.

Put the CF way off the neutral axis and it makes a difference. I don't think there's any disagreement about that, but that's not how most people use it. They use it as Stewmac suggests.

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Re: CF rods and computing neck stiffness

Post by ozwood » Thu Apr 11, 2013 7:17 pm

Michael,

I have been watching from the sidelines, trying hard not to get involved, mostly ......well... erm ...... because I find the whole formulas and maths thing a little :roll: .

But anyway what I do know is Trevor has made a huge contribution to Australian Lutherie, he has and still does take time to generously answer our questions ( witnessed by his section on this forum), he runs a course to complement his book, I found was worth every cent , because it was priced to be affordable to all, pretty much Just covering Trevors time and expenses.

I have since run Into Trevor at The AGMS dinner , and he still was gracious enough to take the time to explain some stuff I did not understand .

I have sent him an Email since seeking help with a problem , he again promptly assisted me.

Maths is not my strong point , but if I get into trouble with a calculation I know I can call Jeff or ask Trevor and they will help me, never once has anyone on this forum scoffed at a question I have asked , rather offering some suggestions on how I might do things better , which I eagerly take on board , I think my guitars sound pretty good and look OK as well, I owe a lot of my success to Trevor and his books.

My point is , this is the culture of this forum, sure from time to time we have some vigorous debates , But I find it just a little......I guess the word is Rude that you Rock up.......... and your first and only contribution is to .........It seems to me anyway............attempt to humiliate Trevor amongst his peers.............. well it's hardly supprising , given our respect for Trevor and his work, you have received the response you have , perhaps what you should have done was wait for final numbers, send a polite email to the effect of .

Dear Trevor ,

I notice in your Book , that you use Hurd's program, however this information has come to light , what are your thoughts ?

I'm sure Trevor , being the enquiring, yet humble man he is would have done his due dilligence and had a good look at it .

Just a suggestion .

Regards,
Paul .

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