Difficulty measuring neck radius

rmackowsky

Strat-Talker
Mar 13, 2021
348
North Carolina
I am setting up a cheapo partscaster. No info available on neck radius. Measuring it with both understring and string off radius gauges. I am nearsighted, so glasses off gives me good clear view. I can't tell the difference between 12" and 14". I have tried using sunlight, flashlight, different viewing angles, measuring on different frets, etc. If I had to choose I would say it's 14", only because I THINK their is slightly more light showing towards the center compared to edges when shining flashlight from behind the 12" radius. Then again there MAY be more light on the edges with the 14".

Does anyone have a trick that will provide the reading with certainty?
 

Guy Incognito

Senior Stratmaster
May 14, 2019
3,848
Here and now
I am setting up a cheapo partscaster. No info available on neck radius. Measuring it with both understring and string off radius gauges. I am nearsighted, so glasses off gives me good clear view. I can't tell the difference between 12" and 14". I have tried using sunlight, flashlight, different viewing angles, measuring on different frets, etc. If I had to choose I would say it's 14", only because I THINK their is slightly more light showing towards the center compared to edges when shining flashlight from behind the 12" radius. Then again there MAY be more light on the edges with the 14".

Does anyone have a trick that will provide the reading with certainty?
The trick I've always used is to not waste time and money on radius gauges. Set up for function and feel. Gauges are at best a starting point that you'll end up tweaking to feel anyway.
 

Geoff06

Strat-Talker
Nov 15, 2021
372
Wisconsin
If you're stuck between the 12" and 14", try using a large compass and make a 13" gauge out of a piece of cardstock or easy-to-cut plastic. You could even attach an Xacto knife to a compass to make the cut. If there are any imperfections in it, try again, until you have a smooth curve.

It's also possible that the fretboard radius is uneven, depending on how it was made.

EDIT:
I understand the knowledge and data craving. I have a document with specific details of my instruments and procedures I've come up with for doing certain repairs or alterations. I used to do instrument repair on the side and I kept a log of everything I did.
 
Last edited:

CB91710

No GAS shortage here
Double Platinum Supporting Member
Feb 24, 2019
10,403
SoCal
To set up the saddles to match. Yea I know I can just set the action on each string equally. Part of me just wants to know.
The strings are above the surface of the neck.
If the neck radius is 12", the frets are 1/8", and the strings are 1/8" above the surface of the frets, then the radius at the strings will be 12.25"

The proper way to do it is to adjust the saddles so the strings are a *consistent* height above the frets.
Note, I did not say *equal*
Typical setup is going to be 5/64 on the bass side and 4/64 or a bit lower on the treble side.

You can take 5 guitars at random off the wall, set every one of them to exactly match Fender or Gibson spec, and half of them will play like crap, and the other half will play fine, but have room to improve.
 

rmackowsky

Strat-Talker
Mar 13, 2021
348
North Carolina
Contour gauge.

TP
Great call on the contour gauge. I found it much easier to determine the radius by first using the contour gauge and then using some music nomad radius gauges to compare to the contour gauge result. And you can do it with the strings on.

I included a couple pictures just to show how obvious the two most extreme radiuses (radii?) are. Determining the difference between 12 inch and 14 inch radius is more difficult, but if you use the top curve of the contour gauge (as opposed to the bottom curve in the pics) and hold it up to the light it’s obvious. Couldn’t get a picture of that with only two hands.

At first I thought the contour gauge actually showed the string action, but then realized that the thinner strings will give more so I wouldn’t put any stock in the string contour.

Overall, maybe useless for some people, but fun for tinkerers like myself. I’ve always struggled trying to appease both the mathematical side of my brain and the creative side. When I’m inspired to play and write, the creative side takes over. But sometimes I have to do crap like this to satisfy the mathematical side before I can keep creating.
 

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TConnelly

Strat-Talk Member
Gold Supporting Member
Mar 9, 2016
81
Sandy, Or.
People often say in these threads "Throw away the tools!" "Set it up by feel!" Well that's great, when one is in their 5th decade of playing guitar. Or even their 5th year. Some people who post here might be in their 5th month playing guitar! For these folks saying "set it up by feel" helps NOT ONE BIT! I feel like a lot of folks on here have been playing so long they've lost their frame of reference when it comes to being a new player. Myself being well inside my first decade playing guitar, I can pretty much eyeball it and "set it up by feel" But since my preferred setup is still kind of a moving target I still measure.

Cheers.............................Todd
 

CB91710

No GAS shortage here
Double Platinum Supporting Member
Feb 24, 2019
10,403
SoCal
People often say in these threads "Throw away the tools!" "Set it up by feel!" Well that's great, when one is in their 5th decade of playing guitar. Or even their 5th year. Some people who post here might be in their 5th month playing guitar! For these folks saying "set it up by feel" helps NOT ONE BIT! I feel like a lot of folks on here have been playing so long they've lost their frame of reference when it comes to being a new player. Myself being well inside my first decade playing guitar, I can pretty much eyeball it and "set it up by feel" But since my preferred setup is still kind of a moving target I still measure.

Cheers.............................Todd
Those of us who have been playing for 40 years didn't even know these tools existed when we learned.
We had a screwdriver, allen wrenches, and our ears and fingers.
Some of us had feeler gauges in the garage, but we didn't have the internet to tell us what numbers we should be looking at.

So we adjusted relief JUST ENOUGH to allow the string to ring with a clear tone when plucked in the middle of the neck.
Then we'd drop the action until it buzzed, then raise it back up. We'd spot check a few bends to see if it fretted out, and if it did, we'd raise it a bit more.
Then we'd tune to a pitch pipe or piano, and set the intonation by ear.

We didn't have all of these tools, and we didn't need them.
And none of that required any elite skills, talent, or knowledge. It either buzzed or it didn't.

And other than using an electronic/strobe tuner, that is still exactly how I do a setup today.
I have the gauges and tools, and only use those as a spot-check when done.
 


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