12" Neck Radius?

[zcostilla]

A lot of people actually prefer a slightly larger radius bridge on electrics (which would also work for many archtops) because it works out for great matching when the bass side is raised slightly higher above the fingerboard than the trebles. This keeps the D and G strings from sitting noticeably higher off the fingerboard than the B and high e, once you get the low E and high e adjusted for the right height.

Edited to add: I doubt you’ll notice the difference of the radius if the bridge is less than 2” larger than the fingerboard.

[zcostilla]

Thanks for all your comments. Rather than the comparison of one radius to another ( I have quiet a few gtrs with different radii and appreciate the different feel) I am more curious as to, for example, having a fretboard radius of say 10" and a bridge radius of say 12" on one guitar , would a player really notice.
I had calculated that the difference in the height of the curve in the centre for those two radii is only 0.0065". Which is less than a very thin string!!
I have just made a couple of templates with those radii out of business cards (watched on youtube) and seen curved sanding blocks being made. It's helluva fine tolerance to achieve especially if it can't be detected by a player. Cheers.

does that calculation include the differences in heights off the fingerboard to allow for string vibration? Theoretically, if the low E sits 0.010” higher than the high e, with each higher string being slightly closer than the string just below it, then wouldn’t the radius arc measured at the bottom of the strings would naturally be different than the fingerboard radius? And 0.010” is just a random number off the top of my head that sounds close, but it gives you a starting point to calculate.

[garybaldy]

No it doesn't but I could have done it - really geeky now! Clearly if the radius was equal at both ends of the strings then, if the low E was higher than the high E (through bridge adjustment), there would be a pro - rata change in height of the other strings. This may suit some players. And, as you say, for example, if the bridge radius was greater (lower curvature) and with the bass side higher, the middle strings would sit lower. At the end of the day it's not really a case of noticing but more a case of what suits the player.
ps FWIW the background to this thread is that on a new guitar I have the bridge saddle is straight so I made the templates to assertain the f/b radius and then shape the bridge to match. I chose to make a 10" and a 12" hoping it would be one of those. Cheers.

[JaxJaxon]

The Radius of the frets will be the same all the way down the neck unless its a compound radius, so if you want a even matching Bridge radius you shape it to the fret radius. I use a radius sanding block to do it. If you have a tune omatic style bridge you get one the same radius as the frets. The big difference between a 7.5 to a 10 or 12 radius to me is how much easyer it is to do Barr chords on a 7.5 than a 12. Yes a higher radius like 12 or 10 wont fret out as much as on a 7.5 But that can be solved by doing a fret fall away leveling.

[AdvenJack]

I am reading that most people report, that it requires LESS physical effort to hold BAR chords firmly,
(such that all the notes ring clearly) on a SMALLER radius F/B. I know that for myself, when fretting
an 'F' BAR chord at fret one, then lifting my middle finger, ring finger and pinky, keeping the index finger
in place to form the BAR, on a friend's FLAT fretboard classical, it feels like it's most natural to apply pres-
sure on strings 1&6. The strings that feel like they're naturally receiving the second most pressure are
strings 2&5. Strings 3&4 feel like they are the naturally receiving the least pressure, and I must focus
more intently to press down on them satisfactorily. So I suppose the SMALLER radius would make sense
for those who use BAR chords a good percentage of the time. Having ZERO classical guitar instruction,
I believe that those who are most active in that discipline, don't use many BAR chords all-in-all.
Further, I'm reading that plucking strings between the bridge and the tip of the fretboard, and strum-
ming, and using a pick to strike individual strings, is more often reported as easiest done with a zero
radius: saddle, fretboard, and nut. I see that as logical.

[Stefan Eff]

I notice that my 10"-14" compound radius plays a lot smoother than my straight 12" radius guitars.

Same here: compound radius from 10-16“. Great.

Especially with the fat U profile (1“ at the 1st, 1“ at the 12th fret). Not everybodys darling, but I love it!

[doc w]

Here is another bit of data to add to the already confusing mix. I bought a 1935 Gibson L-12 a few years ago with a 6" radius. I recently bought another 1935 L-12 which arrived just a few days ago, and it has a compound radius: 7.25" at the nut, gradually becoming about 9.5" by the 8th fret, and continuing as 9.5" to the end of the board.

I have been paying a lot of attention to the radius on vintage Gibsons and have discovered more than a few L-12's with that very round radius. Don't assume that any vintage 17" Gibson has a 12" radius. A guy in Europe showed me some early advertising for the Super 400. which says that the new version of the Super 400 (1937) is going to have a less prominent curve. So at least some early L-12's and Super 400s do not have a 12" radius. Carter Vintage has two 1936 Super 400s for sale, one with a 9.5 inch radius, and one with less than 7.5 inches. Fascinating. What was Gibson doing in those early years?

The L-12 with the compound radius is pretty easy to play. I have 12's on it now and it is easier to play than my previous L-12, but not by much. I would love to see an L-12 with a 12" radius but I can't afford anymore 1930s Gibson arch tops. As Philip Marlowe once said, complaining, about his cash flow, "my wallet just crawled under a duck."