# How to Measure Neck Radius?



## Doug B (Jun 19, 2017)

I've never done this before, but how do you measure neck radius?

Thanks


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## Bubb (Jan 16, 2008)

Print these and cut them out. Need a Set of Neck Radius Gauges? | Pickguardian


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## davetcan (Feb 27, 2006)

Bubb said:


> Print these and cut them out. Need a Set of Neck Radius Gauges? | Pickguardian


That's what I use, work great. It should be noted that the difference is extremely subtle.


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## cboutilier (Jan 12, 2016)

Use a compass to trace a circle at a common size.


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## Doug B (Jun 19, 2017)

Bubb said:


> Print these and cut them out. Need a Set of Neck Radius Gauges? | Pickguardian



Thanks, but I was asking how to actually measure the radius of any given neck with a tape measure, not how to use a template.


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## Adcandour (Apr 21, 2013)




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## Chitmo (Sep 2, 2013)

Doug B said:


> Thanks, but I was asking how to actually measure the radius of any given neck with a tape measure, not how to use a template.


Sounds like you may be confused as to what the neck radius is. Are you confusing it with the scale maybe?


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## Greg Ellis (Oct 1, 2007)

I found this article on the Fender site helpful:

What Is Fingerboard Radius?


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## Wardo (Feb 5, 2010)

cboutilier said:


> Use a compass to trace a circle at a common size.


That’s the usual kinda BS you always get from engineers and if you listen to them you’ll find yourself out on a side road in the middle of nowhere with a varmint rifle and trying to lasso the North Star with a flat wound string ... lol


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## Chitmo (Sep 2, 2013)

Wardo said:


> That’s the usual kinda BS you always get from engineers and if you listen to them you’ll find yourself out on a side road in the middle of nowhere with a varmint rifle and trying to lasso the North Star with a flat wound string ... lol


While fixing a 17 year old Honda!


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## Wardo (Feb 5, 2010)

Chitmo said:


> While fixing a 17 year old Honda!


With vice grips and hammer..lol


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## cboutilier (Jan 12, 2016)

Wardo said:


> That’s the usual kinda BS you always get from engineers and if you listen to them you’ll find yourself out on a side road in the middle of nowhere with a varmint rifle and trying to lasso the North Star with a flat wound string ... lol





Chitmo said:


> While fixing a 17 year old Honda!


I'm only half an engineer. And my Honda is 26 years old!


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## Wardo (Feb 5, 2010)

cboutilier said:


> I'm only half an engineer. And my Honda is 26 years old!


There is an evil demon lurking in the Honda; it will posses you and the Honda will start getting younger while you get exponentially older ... lol


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## cboutilier (Jan 12, 2016)

Wardo said:


> There is an evil demon lurking in the Honda; it will posses you and the Honda will start getting younger while you get exponentially older ... lol


We're the same age, but it has aged better than me.


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## Bubb (Jan 16, 2008)

Doug B said:


> Thanks, but I was asking how to actually measure the radius of any given neck with a tape measure, not how to use a template.





Chitmo said:


> Sounds like you may be confused as to what the neck radius is. Are you confusing it with the scale maybe?


Yeah ,you can't measure it with a tape measure.
The radius of a neck is actually just the curve of the fingerboard and frets across the neck.
That link to the Fender site that Greg E posted above is a good clear explanation.


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## Guest (Mar 8, 2018)

You could use a tape measure if you cut the neck off at the 12th fret.


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## Doug B (Jun 19, 2017)

Chitmo said:


> Sounds like you may be confused as to what the neck radius is. Are you confusing it with the scale maybe?


Not the scale, but I was confused as to terms. Old vintage necks are usually said to be 7.5", right? What does that measure-back to front? Yet newer necks are said to be 14-16"? I better quit before I totally confuse myself!


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## Doug B (Jun 19, 2017)

Wardo said:


> That’s the usual kinda BS you always get from engineers and if you listen to them you’ll find yourself out on a side road in the middle of nowhere with a varmint rifle and trying to lasso the North Star with a flat wound string ... lol


Sounds like my first and last time using a GPS!


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## Chitmo (Sep 2, 2013)

Doug B said:


> Not the scale, but I was confused as to terms. Old vintage necks are usually said to be 7.5", right? What does that measure-back to front? Yet newer necks are said to be 14-16"? I better quit before I totally confuse myself!


My best simple description is that the radius refers to the roundness or curve of the fret board. Small number = more curved..... bigger number = more flat


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## davetcan (Feb 27, 2006)

cboutilier said:


> Use a compass to trace a circle at a common size.


He'd need a beam compass.


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## davetcan (Feb 27, 2006)

Doug B said:


> Thanks, but I was asking how to actually measure the radius of any given neck with a tape measure, not how to use a template.


You can't.

Given the arc length and chord length, what is the radius? - Math Central


Trust me, print off a damn template.


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## davetcan (Feb 27, 2006)

Player99 said:


> You could use a tape measure if you cut the neck off at the 12th fret.


Not really. At least not without a lot of string and patience. Or you could trace the profile and go from there, at which point you'd wish you'd printed off the fucking template.


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## Guest (Mar 8, 2018)




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## davetcan (Feb 27, 2006)

Yep. Good luck figuring that shit out with a tape measure 



laristotle said:


>


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## Ronbeast (Nov 11, 2008)

davetcan said:


> Yep. Good luck figuring that shit out with a tape measure


It’s possible, but after all of the time and effort to figure it out, you’d basically be at the same step you’d be at if you just printed the template.

I’m gonna side with Davetcan on this one; print the template.

P.s. the different templates are also helpful when setting the string arc on strats, just an fyi.


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## davetcan (Feb 27, 2006)

Now you've got me curious. The only 2 things you can measure with a tape measure are the arc length and the chord length (width of fingerboard). How do you get from there to the actual radius?

If you could accurately also measure the height of the segment then you'd have a shot. Still much more involved than a tape measure though, LOL.



Ronbeast said:


> It’s possible, but after all of the time and effort to figure it out, you’d basically be at the same step you’d be at if you just printed the template.
> 
> I’m gonna side with Davetcan on this one; print the template.
> 
> P.s. the different templates are also helpful when setting the string arc on strats, just an fyi.


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## Ronbeast (Nov 11, 2008)

davetcan said:


> Now you've got me curious. The only 2 things you can measure with a tape measure are the arc length and the chord length (width of fingerboard). How do you get from there to the actual radius?


It’s not taking a direct measurement with the tape, and I agree with you 100% about printing the templates, so here’s my raw homebrew method; I know it’s not the best way, it’s just a way that you COULD do it, if in a pinch.

If it’s a 12” radius, set the tape measure to 12” and lay it on a large piece of paper with a dot marking the centre of the sheet. Rotate the tape measure 360 degrees and follow the clasp with a fine point pencil. When your circle is drawn, cut it out and discard it; we want the piece of the paper with the circles radius cut into it. 

You can use this method to make templates of all standard sizes, the only problem is it’s infinitely easier to just print them off online because somebody else has already put in the work.

Obviously this method assumes you’re steady with a tape measure and it can’t be used for a compound radius.

For myself; I just print the templates online. I just have this thing where I like proof of concept and to see where these design choices come from.


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## davetcan (Feb 27, 2006)

So just for fun I did this.

Tools of the trade (ditched my drafting board many years ago)










I assumed a 2" wide neck just to make things easy. Marked the center line and the used the beam compass to scribe 2 intersecting arcs from the intersections of the "edge of the fingerboard". I did this for a 7.5" radius and a 9" radius. 










Please note that the two arcs are almost exactly on top of each other. Makes you wonder what all the fretboard radius fuss is all about doesn't it. 










Also please note that I can't do any of this with just a tape measure in one hand and a guitar neck in the other.


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## davetcan (Feb 27, 2006)

Ronbeast said:


> It’s not taking a direct measurement with the tape, and I agree with you 100% about printing the templates, so here’s my raw homebrew method; I know it’s not the best way, it’s just a way that you COULD do it, if in a pinch.
> 
> If it’s a 12” radius, set the tape measure to 12” and lay it on a large piece of paper with a dot marking the centre of the sheet. Rotate the tape measure 360 degrees and follow the clasp with a fine point pencil. When your circle is drawn, cut it out and discard it; we want the piece of the paper with the circles radius cut into it.
> 
> ...


So you're making a template


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## Bubb (Jan 16, 2008)




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## Ronbeast (Nov 11, 2008)

davetcan said:


> So you're making a template


Yes, as we’ve agreed, that’s the easiest way. I’m sure there is some way of figuring it out with roundabout trigonomics and a measuring tape, but I value my time and hitting “print” makes life easier in this case.


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## Steadfastly (Nov 14, 2008)

I am wondering if there is some tool similar to a set of collapsible "feeler" gauges that would work on a neck so when you pressed it against the neck, it would collapse and form a concave in the shape of the convex of the neck. 

You could quite easily do this with play putty and then measure the diameter of the circle.


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## vadsy (Dec 2, 2010)

Steadfastly said:


> I am wondering if there is some tool similar to a set of collapsible "feeler" gauges that would work on a neck so when you pressed it against the neck, it would collapse and form a concave in the shape of the convex of the neck.
> 
> You could quite easily do this with play putty and then measure the diameter of the circle.


wonder no more Steadly! here you go,..
Understring Radius Gauges | stewmac.com

I suggest having them shipped to the border and picking them up yourself to save 3 or 4 bucks but waste a day putzin around

edit - here is another one, just in case googling is hard Radius Gauges | stewmac.com


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## Guest (Mar 8, 2018)

Steadfastly said:


> tool similar to a set of collapsible "feeler" gauges


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## Bubb (Jan 16, 2008)

Steadfastly said:


> You could quite easily do this with play putty and then measure the diameter of the circle.


With putty ?lol 
Hard to keep soft putty in the exact shape,see Dave's post as to how close the shapes really are.
Think that is easier than cutting out a pre-made template ?

The profile gauge that @laristotle posted is the ideal tool,but you still have to go through the process of measuring.,and unless you are a cabinet maker or finishing carpenter you probably don't have one.


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## Steadfastly (Nov 14, 2008)

Bubb said:


> With putty ?lol
> *Hard to keep soft putty in the exact shape*,see Dave's post as to how close the shapes really are.
> Think that is easier than cutting out a pre-made template ?
> 
> The profile gauge that @laristotle posted is the ideal tool,but you still have to go through the process of measuring.,and unless you are a cabinet maker or finishing carpenter you probably don't have one.


Putty only gets soft when it gets warm from using it for awhile. .I could do this quicker than using a template. Just make sure the quantity of putty is large so it retains its shape.


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## vadsy (Dec 2, 2010)

Steadfastly said:


> Putty only gets soft when it gets warm from using it for awhile. .I could do this quicker than using a template. Just make sure the quantity of putty is large so it retains its shape.


brilliant,,. can I buy this putty at my local hardware store or do I have to have it shipped?


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## Guest (Mar 8, 2018)

Anyone remember their high school calculus?
I'm sure there's a formula there somewhere.


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## Bubb (Jan 16, 2008)

Steadfastly said:


> Putty only gets soft when it gets warm from using it for awhile. .*I could do this quicker than using a template.* Just make sure the quantity of putty is large so it retains its shape.


So,to be clear,you could..
1) get putty,
2)form it to the fingerboard
3)remove from fingerboard
4) draw 4-8 different circles
5 )find a match with your putty

Do this faster than matching the curve one of 2 precut,measured and marked templates.(which you can save and use anytime after)

You are amazing


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## vadsy (Dec 2, 2010)

laristotle said:


> Anyone remember their high school calculus?
> I'm sure there's a formula there somewhere.


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## Bubb (Jan 16, 2008)

laristotle said:


> Anyone remember their high school calculus?
> I'm sure there's a formula there somewhere.


Hell I barely remember high school. Period.


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## vadsy (Dec 2, 2010)

Bubb said:


> So,to be clear,you could..
> 1) get putty,
> 2)form it to the fingerboard
> 3)remove from fingerboard
> ...


imagine what he could do with a compass and a slide rule


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## Bubb (Jan 16, 2008)

vadsy said:


> imagine what he could do with a compass and a slide rule


Get Gibson back on track ? B#(*


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## vadsy (Dec 2, 2010)

Bubb said:


> Get Gibson back on track ? B#(*


he could do that in his sleep, no tools required, but he chooses not to


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## davetcan (Feb 27, 2006)

There isn't.



laristotle said:


> Anyone remember their high school calculus?
> I'm sure there's a formula there somewhere.


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## Guest (Mar 8, 2018)

I would use chocolate chip cookie dough.


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## Guest (Mar 8, 2018)

davetcan said:


> There isn't.


If you know the height, width and length of the partial circumference there must be. That's why I recommended cutting off the neck at the 12th fret.


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## davetcan (Feb 27, 2006)

Player99 said:


> If you know the height, width and length of the partial circumference there must be. That's why I recommended cutting off the neck at the 12th fret.


Well there are all kinds of ways given the correct, and enough, information, but getting back to the OP, he asked if he could just do it using a tape measure. The correct answer is no. 

You could also use this - scroll down about halfway.

Online calculator: Circular segment


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## Chitmo (Sep 2, 2013)

vadsy said:


> he could do that in his sleep, no tools required, but he chooses not to


Worst part about all this banter about Steady is that he doesn't see any of it. He's got 90% of the forum members blocked!


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## Steadfastly (Nov 14, 2008)

Bubb said:


> So,to be clear,you could..
> 1) get putty,
> 2)form it to the fingerboard
> 3)remove from fingerboard
> ...


Okay, maybe not quite as fast but if I had the materials on hand, I could do it in about five minutes.


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## vadsy (Dec 2, 2010)

Chitmo said:


> Worst part about all this banter about Steady is that he doesn't see any of it. He's got 90% of the forum members blocked!


unfortunate for him, he’s really missing out


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## LanceT (Mar 7, 2014)

Steadfastly said:


> Okay, maybe not quite as fast but if I had the materials on hand, I could do it in about five minutes.


As suggested, if you use cookie dough, you could also bake some cookies after.


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## Guest (Mar 8, 2018)

The easiest way, unless it's a really obscure guitar, is to google your guitar's specs.


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## Bubb (Jan 16, 2008)

Steadfastly said:


> Okay, maybe not quite as fast but* if I had the materials on hand*, I could do it in about five minutes.


There's the rub,in post #2 I provided the link for the templates.
I didn't have the link for silly putty .



laristotle said:


> The easiest way, unless it's a really obscure guitar, is to google your guitar's specs.


Well ya,but then we wouldn't have 4 pages of this.
Whatever this is .


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## Doug B (Jun 19, 2017)

Chitmo said:


> My best simple description is that the radius refers to the roundness or curve of the fret board. Small number = more curved..... bigger number = more flat
> 
> View attachment 179857



Thanks, Chitmo. Perfect concise explanation. (Unlike the Wannabee engineers.


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## Ronbeast (Nov 11, 2008)

Doug B said:


> Thanks, Chitmo. Perfect concise explanation. (Unlike the Wannabee engineers.


It’s a good explanation, but it doesn’t answer your question of how to measure the radius with a measuring tape.

You can crap on the “wannabe engineers” all you want, but you asked for the help. It’s not our fault that the answers aren’t perfectly tailored to you.

I see at least two or three different options for you to find the information you seek; I’m sure even the almighty google would be happy to regurgitate it for you.


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## cboutilier (Jan 12, 2016)

davetcan said:


> There isn't.


Don't forget you can iterate the equation using the common radii until you get a solution. You can measure the chord length, arc length, and then assume the radius to be (7.25, 9.5, 10, 12, 14).


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## davetcan (Feb 27, 2006)

cboutilier said:


> Don't forget you can iterate the equation using the common radii until you get a solution. You can measure the chord length, arc length, and then assume the radius to be (7.25, 9.5, 10, 12, 14).


We don't like assumptions


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## cboutilier (Jan 12, 2016)

davetcan said:


> We don't like assumptions


The assumption is only an educated starting point for an iterative calculation.


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## davetcan (Feb 27, 2006)

cboutilier said:


> The assumption is only an educated starting point for an iterative calculation.


OK, let's assume you know the radius is 10". What dimensions would you need to confirm it? A tape measure will give you the width of the fretboard (chord length). I still think you're going to need the segment height to determine arc length. That is not going to be easy with a tape measure, especially given the subtle differences between the radii, and the rolled edges. 

Is/are there easier dimensions to take that I'm not thinking about?


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## BSTheTech (Sep 30, 2015)

I have radius templates. Ship me your guitar with a pre-paid return label and I'll let you know B#(*

Or check Ebay/AliBaba for knock off versions of these for 1/4 the price.

Understring Radius Gauges | stewmac.com


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## cboutilier (Jan 12, 2016)

davetcan said:


> OK, let's assume you know the radius is 10". What dimensions would you need to confirm it? A tape measure will give you the width of the fretboard (chord length). I still think you're going to need the segment height to determine arc length. That is not going to be easy with a tape measure, especially given the subtle differences between the radii, and the rolled edges.
> 
> Is/are there easier dimensions to take that I'm not thinking about?


I'd use a piece of string to measure the arc length of the fret


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## davetcan (Feb 27, 2006)

cboutilier said:


> I'd use a piece of string to measure the arc length of the fret


So you wouldn't need the height? Forgive me, I haven't had to think for about 3 years 

edit - if you know the width, or chord length + radius + arc length then you can determine the height. Still can't measure it though.

Perhaps we should open a geometry thread, LOL.


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## cboutilier (Jan 12, 2016)

davetcan said:


> So you wouldn't need the height? Forgive me, I haven't had to think for about 3 years
> 
> edit - if you know the width, or chord length + radius + arc length then you can determine the height. Still can't measure it though.
> 
> Perhaps we should open a geometry thread, LOL.


I'll have to dig out my old calculus notes. I'll do the math this weekend and see what I come up with.


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## davetcan (Feb 27, 2006)

cboutilier said:


> I'll have to dig out my old calculus notes. I'll do the math this weekend and see what I come up with.


No,no, no, you can only use a tape measure, LOL.

Or if you also have a calculator

Chord length given the length & radius of an arc - Math Central


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## davetcan (Feb 27, 2006)

@Doug B , hopefully you're ignoring all of this crap, sorry


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## cboutilier (Jan 12, 2016)

davetcan said:


> No,no, no, you can only use a tape measure, LOL.
> 
> Or if you also have a calculator
> 
> Chord length given the length & radius of an arc - Math Central


I think I can calculate the radius with measured values. Give me a few moments to get home and I'll see what I come up with.


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## davetcan (Feb 27, 2006)

cboutilier said:


> I think I can calculate the radius with measured values. Give me a few moments to get home and I'll see what I come up with.


If I still had my CAD station ............


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## cboutilier (Jan 12, 2016)

davetcan said:


> If I still had my CAD station ............


No need. I have a napkin.

180A=2R(pi)(sin^-1(C/2R))

Where A is the measured arc length, R is the unknown Radius, C is the measured chord length.


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## davetcan (Feb 27, 2006)

cboutilier said:


> No need. I have a napkin.
> 
> 180A=2R(pi)(sin^-1(C/2R))
> 
> Where A is the measured arc length, R is the unknown Radius, C is the measured chord length.


I rest my case  (get a template)


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## cboutilier (Jan 12, 2016)

I just proposed this problem to my guitarist friend with a Masters in Applied Mathematics.


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## davetcan (Feb 27, 2006)

LOL, excellent. I was going to suggest you grab one of your Teles and test your formula. Assuming you're dealing with a 7.25 Radius and either 1 5/8 or 1 11/16 nut width you should be able to solve for "A" and see how close you get to a tape measurement of the neck arc length.


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## cboutilier (Jan 12, 2016)

davetcan said:


> LOL, excellent. I was going to suggest you grab one of your Teles and test your formula. Assuming you're dealing with a 7.25 Radius and either 1 5/8 or 1 11/16 nut width you should be able to solve for "A" and see how close you get to a tape measurement of the neck arc length.


Thats the plan when I get home.


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## davetcan (Feb 27, 2006)

cboutilier said:


> Thats the plan when I get home.


Assuming a 1.625 neck and 7.25 radius I get a arc length of 1.628.

Assuming a 1.625 neck and 9.5 radius I get a arc length of 1.627.

Good luck 

edit - at the extreme 16" radius the result is 1.625. - the "2R's" in the equation essentially cancel each other out but given the very short chord length and the quite large radii I would have expected the arc lengths to be very close to the chord lengths. I think your formula is good, it's just too close to be of any use for measurement with a tape measure.

It always surprises me how easy it is to "feel" the difference as opposed to seeing it


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## cboutilier (Jan 12, 2016)

davetcan said:


> Assuming a 1.625 neck and 7.25 radius I get a chord length of 1.628.
> 
> Assuming a 1.625 neck and 9.5 radius I get a chord length of 1.627.
> 
> ...


I figured that would be the case in a practical application.


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## Guest (Mar 10, 2018)

davetcan said:


> Assuming a 1.625 neck and 9.5 radius I get a chord length of 1.627.


And where can anyone buy a tape measure with those increments?


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## cboutilier (Jan 12, 2016)

laristotle said:


> And where can anyone buy a tape measure with those increments?


A machinists ruler is marked in 32nds and sometimes 64ths


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## davetcan (Feb 27, 2006)

laristotle said:


> And where can anyone buy a tape measure with those increments?



I just edited my post, should have said "arc length", the chord length is the neck width


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## Guest (Mar 10, 2018)

Dave just answered my question.
I have a half dozen from my dad and gramps.
Technology's sure come a long way. doh!


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## cboutilier (Jan 12, 2016)

laristotle said:


> Dave just answered my question.
> I have a half dozen from my dad and gramps.
> Technology's sure come a long way. doh!


Like I told my students when they saw their first measuring tape: its a ruler on a roll.


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## Bubb (Jan 16, 2008)




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