Gibson bridge radius screw-ups

[Brian Hart]

This is the second time in two week's I've gone to set up a relatively new US made SG and this happens.  The original bridge has a radius of something in the 17 to 18in radius range, nowhere near the factory fretboard radius of 12.  Made for a pretty awful setup before the problem was corrected.  Is this as commonplace as I think it is?

[Russell Vance]

Hello Brian (in absentee),

Couple of things here, have you ever noticed when setting up something like a Strat that the strings get a bit higher towards the bass side of the board to allow for their increasing elliptical path to clear the frets.  

This effectively changes the radius of the strings at the bridge to a somewhat flatter version of the standard 9.5" radius or so, which is what you get when you tilt a flatter radiused TOM to achieve a bit more clearance on the bass side.   It's a nuanced thing and not addressed in the 101's which tend to favor a standard fret radius gauge approach to all ills - I use gauges but understand that a 12" may more suitable to set up a 9.5" radius neck etc.  

What Paul said is just geometry and technical technique combined to give a solution to the problem at hand - hardly elitist stuff or opinion - it's just a quick cut to the chase from someone who has more time on the tools than most of us but very little free time to get the message across.  Breath.

Regards,

Rusty. 

[steven gallagher]

Hi Rusty,

Do strings travel in an elliptical path? Physics books always describe their path as sinusoidal. Of course, there are overtones/harmonics as well, but those are also sinusoidal.

I realize this has probably no effect on guitar setup. Just curious.

[Stewart C Simon]

Gibson's bridges are still made with '50's manufacturing technology.

Cast out of Mazak and poorly machined everything else that creates huge variances in all aspects drastically effecting doing a proper Setup….radius problems, saddles that won't move or stay put, loose screws, etc.

Plus tonally…pot metal isn't exactly a good sonic transfer…

Put a Callaham T.O.M. on it …;-)

[Russell Vance]

Hi Steven,

The sonic frequency generated by a plucked string is sinusoidal (ie: back and forth/up and down in a layman's speak) and the  movement becomes what is known is know as "lambda" or wavelength.  That frequency, in this case is generated by a string subscribing a roughly (its a complex subject) eliptical path if plucked "pure" and generating a frequency dependent on its fretted length.  There are also harmonics generated and string "wobbles" dependent on where the string is plucked but that another story.

Also roughly speaking that's why we put in some elliptical relief in the neck during set-up - to allow the string to travel it's fundamental path without banging into the frets.   There is a whole lot more happening but that just the basics upon which we build our knowledge.

Gotta fly, the guitars (and customers) are on my case.

Regards,

Rusty.

[steven gallagher]

Rusty,

I did a little googling on this subject, e.g. "does a string vibrate in an elliptical pattern", and found the idea quite rampant in luthier circles. I don't know how the idea got started, but it has definitely taken root.

Perhaps Peter Poyser could add a few words.   :-)

[Robbie Collins]

A heavy guitar isn't necessarily a good thing unless you only want the sound of the pickups.  Heavier wood takes a lot of acoustic energy to excite it into resonance.  There is a question as to how the sound of the wood could be captured by any solid body electric guitar but I suppose the bridge and pickups could move very subtly.  In any case, a lighter guitar is better at preventing back problems later on down the line.

[Robbie Collins]

I really like these:

http://www.callahamguitars.com/abr1.htm

[Stewart C Simon]

Me as well…the BEST ABR-1 T.O.M. out there…!!!

I have one on my Firebird VIII, and have installed several of them on LP's and 335's.

They make an amazing difference in clarity, definition, and stability…:-)

[Russell Vance]

Yep, we use their stuff for the occasional clone and it's just plain straight good.   Would recommend this gear on the basis of it's high quality.  Thumbs up.

Rusty.