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Crowning saddle height to match fretboard radius

John Coloccia

Cold Supporting Member
Messages
9,580
In practice, if the neck is a simple radius (i.e. shaped like a cylinder, not a cone), setting the bridge to match the fingerboard radius works out. Just take a tunomatic as an example, because without working it the radius is generally set. I would generally set the bass strings bit further from the fingerboard (a fat 1/16", for example), and the treble strings are a bit closer (1/16"...maybe a touch under or dead on). This is just as an example. It works out fine and not really appreciably different than I would set individual saddles on a Fender, for example.

I just did a guitar a few months ago with an LR Baggs piezo tunomatic. It comes with a 10" radius. That's tighter than the 12" radius fingerboard I happen to build. I didn't do anything special, and it plays just as well as anything else I've built. I was prepared to flatten it out, but is was completely unnecessary.

I don't want to say it's not critical, because everything makes a difference, but it's just not that critical. Believe me, before we had radius gauges, radius sanding blocks, fancy neck swinging belt sanders, CNC machins, cheap micrometers, dimensional nut files, and everything else, we built guitars using our eyeballs and our hands to feel what was going on, along with crude metal working files to do frets, nuts and bridges. All those vintage guitars we lust after were built with feel and eyeballs. If you've ever worked on an old LP, you know that fingerboard, fret and bridge radiuses are all over the place, and they still play well.

Again, I'm not advocating sloppiness...we can reasonably do better today so we should, but don't get bent around the axle trying to engineer it to death. If you have a simple radius, generally matching the radius on the bridge works well, and measuring the individual string heights works well too. For a compound radius, forget about the radius and just measure the string heights. Personally, I've tried using radius gauges for the bridge, and just find them to be inconvenient and generally difficult to use, so I measure everything. Not with dial indicators and micrometers. I capo at the first and eyeball my trusty 6" rule at the 17th.
 

VaughnC

Silver Supporting Member
Messages
17,746
I know this isn't proportional, because like Mark I normally don't measure things I just work on the guitar until it feels, plays and sounds right, but:

Would you consider taking a radius guage and checking the radius at the nut (say 7.25) and then seeing if that 7.25 really carried over to the saddles on a guitar out of the packaging? I've tried it a few times and the value is always higher, i.e., the radius is flatter at the saddles. It does NOT match, in my experience.

But sure, I will concede I push the radius even flatter than what I find, normally, out of the box. In just the very simplest terms, while the relative heights of the strings vis a vis one another may stay the same, the spacing between each string grows a lot whether the string array at the nut is 1 + 3/8ths or less or more, and whether the string array at the saddles is 2 + 1/8ths inches or less or as much as 2 + 7/32nds inches. The math is, when the relative heights remain the same but the strings get that much further apart, the radius has changed.
Yup, I agree with this.

However, when setting up a Strat, they all aren't exactly the same. Some need more relief and some need less to play their best...and how the player plays the guitar factors in too. Its that delicate balance between action, relief, and trem setup than can make or break a Strat. But, when looking at the rear of the bridge, I always set the saddles flat to the plane of the body top.
 

RAILhead

(real name is Maury, BTW)
Messages
4,642
For me, it's about having a starting point -- a set of common denominators to use as a take-off. In my 25 years, the way I do it has been working for me and the clients I service. Beyond the generic setup, it then becomes a matter of tweaking each guitar to fit the specific player. There's a reason manufacturers have factory specs: they serve as excellent take-off settings. In my experience, the vast majority of players are content with those settings.
 

Tone_Terrific

Silver Supporting Member
Messages
32,091
Take 2 paint cans (the lager ones) and put them end to end. One is the fretboard and one is the bridge.
Now raise one of them to simulate how the saddles are raised above the level of the nut.
Note how the upper can radius now proceeds to drop towards that of the lower can as one moves around the circumference. This shows how a matched radius of the bridge cannot bring the strings into exact parallelism to the fretboard, nor is it necessary.
The strings fan out at the bridge. The radius must flatten.
I can't supply the specs, but it seems to be quite clear.
 

walterw

Platinum Supporting Member
Messages
37,729
+1

in situations where you do need to describe an exact radius arc at the bridge ahead of time (namely when shaping acoustic saddles), a radius that's an inch or two larger than the board radius works out just right, even when the board itself isn't compounded.
 

Chris Scott

Member
Messages
9,062
Cool thread.

I've been setting up my (and a lot of client's as well) 7.25 rad. guitars with a 9.5 rad. gauge lately with great results.

... call me a contrarian. Go ahead...;)
 

murrayotl

Member
Messages
2
Hey, I can use some help.I had a work accident and now disabled. My wife brought me tools to work on guitars with.Playing for a couple of years now. Have some old guitars trying to fix as a hobby. I spend a lot of time in home due to 14 back surgeries. So I was interested in guitar setups and minor repairs.She got me these understring radius gauges and not sure how to use properly. Thanks for any guidance and help. John
 

John Coloccia

Cold Supporting Member
Messages
9,580
Hey, I can use some help.I had a work accident and now disabled. My wife brought me tools to work on guitars with.Playing for a couple of years now. Have some old guitars trying to fix as a hobby. I spend a lot of time in home due to 14 back surgeries. So I was interested in guitar setups and minor repairs.She got me these understring radius gauges and not sure how to use properly. Thanks for any guidance and help. John
They're the ones with the little handles on them? You can use them a couple of ways.

On a tunomatic, stick them under the strings at the bridge and use that as a guide to file the saddles down to meet that radius. You can lightly push on the strings to see which ones are sitting on the gauge and which ones aren't. Then you can adjust the posts to whatever action you want.

On a guitar with individually adjustable saddle, set the low and high E to whatever action you want, and raise all the strings in between to something that's too high. Then stick the gauge under the strings at the bridge (it will only rest against the low and high E) and bring down the center strings to match the gauge.

Honestly, I find them kind of difficult to use. Other people find them easy to use.
 

macatt

Member
Messages
1,416
Not rude at all and I agree.
For myself; I just do it by eye and feel. I can sight accross the strings and judge the radius.
I usually raise the little E and B strings just a little higher. They seem to ring out a bit better that way.
S Mac
 

Dana Olsen

Platinum Supporting Member
Messages
7,902
Railhead said:
The bridge saddles should *always* match the fretboard radius as closely as possible.
I don't think Railhead is arguing in favor of canting the saddles here, just about the height of each individual saddle. I find that for me mostly the string height follows the fret board radius, with the caveat as Boris points out that the middle strings don't need as much clearance over the frets as the outside strings do because the act of bending the (higher) strings moves the string CLOSER to the fret top during the bend, and the lower string have more excursion when played harder.

That said ....

Boris Bubanov said:
1) the individual style saddles should not be canted but should be parallel to the plane of the guitar body. The string stays put better, and screws stay put also. Saddles press down on the bridgeplate and don't lean against one another and there's less trashy sounds;
I think this is an extremely important point that can't be overstated.

Each string will make better contact with the bridge plate and sustain better when the adjustable 'feet' on both sides of a Strat or Tele (six saddle type) saddle are bearing equal pressure - NOT CANTED, square to the plane of the bridge plate. When there is equal pressure on both feet, that's the most solid contact and is the most optimum adjustment, IMHO.

It makes a huge difference, in my opinion, when all 6 saddles are, er, standing on their own two feet (GRIN)

Thanks, Dana O.
 
Messages
2,176
Take 2 paint cans (the lager ones) and put them end to end. One is the fretboard and one is the bridge.
Now raise one of them to simulate how the saddles are raised above the level of the nut.
Note how the upper can radius now proceeds to drop towards that of the lower can as one moves around the circumference. This shows how a matched radius of the bridge cannot bring the strings into exact parallelism to the fretboard, nor is it necessary.
The strings fan out at the bridge. The radius must flatten.
I can't supply the specs, but it seems to be quite clear.
I'm not convinced.

For instance, the action at the nut on my Les Paul conforms to a 12" radius. The radius at the bridge is 12". Using a ruler to measure the difference in the height of the strings across the 12th fret shows the difference in height between each string is equal, which means the shape of the strings across the 12th fret conforms to the radius of the fingerboard and the bridge.

I performed the same measurements on a 10"-16" compound radius fingerboard. Now obviously the strings will conform to a cone shape and assume a flatter radius as the strings approach the bridge, but with the nut cut at a 10" radius, and the strings forming a 16" radius at the end of the fingerboard, the difference in height between the strings across the 12th fret is equal, just as it is with the LP, which shows me the shape of the strings matches the radii of the fingerboard.
 

Mark Robinson

Platinum Supporting Member
Messages
8,418
I'm not convinced.

For instance, the action at the nut on my Les Paul conforms to a 12" radius. The radius at the bridge is 12". Using a ruler to measure the difference in the height of the strings across the 12th fret shows the difference in height between each string is equal, which means the shape of the strings across the 12th fret conforms to the radius of the fingerboard and the bridge.

I performed the same measurements on a 10"-16" compound radius fingerboard. Now obviously the strings will conform to a cone shape and assume a flatter radius as the strings approach the bridge, but with the nut cut at a 10" radius, and the strings forming a 16" radius at the end of the fingerboard, the difference in height between the strings across the 12th fret is equal, just as it is with the LP, which shows me the shape of the strings matches the radii of the fingerboard.
The issue is that the nut is narrower than the bridge, so that means the chord length of the two arcs are not identical. So if you have the same "rise" at these two chord lengths, the arc with the longer chord length has a longer or flatter radius.
 

guitarcapo

Senior Member
Messages
2,333
The bridge saddles should *always* match the fretboard radius as closely as possible.
If the fretboard has a single fretboard radius along its entire length (cylindrical), the saddle should be a little steeper than the fretboard in radius.

If the fretboard is compound radius, the saddle should be a little flatter than the fretboard radius at the last fret.

Lately the way I set up my acoustics (when single radius) is the used a radiused board to shape the saddle to the same radius as the fretboard.

Then I string up the guitar and let all the wood movement under tension occur.

Then I shave down the bottom of the saddle until I just start hearing buzz playing heavily on the d and G strings.

Then I shave down a little more than this on the saddle top at each end to increase radius there.

Works great....but of course compound radius is better.
 

walterw

Platinum Supporting Member
Messages
37,729
If the fretboard has a single fretboard radius along its entire length (cylindrical), the saddle should be a little steeper than the fretboard in radius.
why steeper? you end up with higher action on the middle strings, but what else does it do for you?

with acoustics i like it slightly flatter regardless, as that seems to work out well with the way the strings spread as they reach the bridge. (i mean "slightly" as in maybe a 15" saddle on 14" frets.)

with electrics i'm just measuring off a certain fret and setting each string accordingly, which works out well regardless of radius, compound or not (even with fender's 7 1/4" curve, which really is too steep; there we're looking at "hillbilly compound radius" like the man said, which with teles also helps to even out the string response over the flat-poled pickup).
 

WahmBoomAh

World Crass Guitarist
Gold Supporting Member
Messages
3,566
can`t say I understand it all ... but it makes one hell of a read ... thanks guys
 

bullfrogblues

Gold Supporting Member
Messages
3,065
I agree with John. My method is to measure and adjust each string to a given height at the 21st or 22nd fret. That automatically matches the radius of the fretboard to the bridge saddles. Fine tune from there to eliminate buzzing.
 

Gannon

Member
Messages
1
In a symmetrical universe full of symmetrical players, that might be the case, but the truth is there are quite a number of professional players that like the saddle radius on electric guitars to be flatter / larger than the radius of the fingerboard. I know a few players that want the strings flat (zero radius) regardless of the fingerboard radius.
Yep, the bridge should be set to match the radius. 9.5" fretboard = 9.5" bridge. 12" fretboard = 12" bridge. 10"-16" radius = the closest natural progression, which I would still keep at 16", but 20" would be erectly fine.
I reset my password to leave this comment!!! The truth is, is that this piece of info saved me. I would have never tried the 20" radius guage, and it is exactly what this 2001, USA strat needed......Plus a few tweaks on the B and E string, but just saying, this gets a person MUCH closer than the 9.5" or the 12" radius guage!! That is my two cents!!
Cheers, and thank you for saving me all day, and maybe more figuring it out for my self or reading on the comp for days!!
 

Ray175

Member
Messages
393
Agree with many comments and points made. The exception I make is for slide - personally I prefer all 6 strings to be at the same hight for sliding chords on several strings. YMMV.
 




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