Bridge positioning

[Tonemeister]

I believe my bridge posts are placed too far back, at the factory, and therefore my scale length is off. I have to have all but the Low E string saddle full forward. I can't actually even get the A string to intonate.

Here's some background.

Bought the guitar new from Sam Ash a couple of weeks ago. It is a Chris Cornell Sig ES335 Dot with Bigsby. Absolutuely awesome guitar. Have not been able to get the guitar to stay in tune at all since I bought it. Tried filing the nut, lubing nut and saddles etc. Didn't work. Then tried going up to 11's which is a supposed better gauge for the Bigsby. Still no dice. Finally resorted to getting a TonePros roller bridge. I widened the nut slots more aggressively this time. In addition I added a little teflon tape to the bridge posts in order to firm that up more. There was a bit of wiggle prior to that. I also adjusted the truss rod to make the neck perfectly flat with less than a mm of relief at the 12th fret. Now I am in a good place with the guitar staying in tune and the guitar seems louder, acoustically, than it did before the mod. My problem is that when I measure the length from nut to the front edge of the 12th fret, I get the same measurement from the front of the 12th fret to the high E saddle when it is all the way at the front of the bridge. This leaves no room for adjustment on most of the strings and in a few cases leaves the string flat at the 12th fret , even though the saddle is all the way forward. Does anyone know how to fix this without relocating the bridge posts?

 

[cmjohnson]

If the bridge location is wrong and you can't intonate it, that guitar needs to be replaced. Nothing less would ever satisfy me.

 

[Tonemeister]

bump for help

 

[SGeoff]

I guess you could get a harminica type bridge. they are wider and will give more adjustment. I would consider, since its basically brand new, taking it back for one that can be intonated correctly.

 

[Tonemeister]

So is there a measurement that I should take from the 12th fret to the bridge posts or something? I don't want to have to take the new roller bridge off and put the old Nashville TOM on there if I can avoid it.

 

[ARandall]

Essentially you should be able to measure the 'advertised' scale length on the low E to the centre of the bridge holes/mounting stud.

 

[Tonemeister]

Essentially you should be able to measure the 'advertised' scale length on the low E to the centre of the bridge holes/mounting stud.

Ok that's what I was thinking too. I'll try that. Thanks.

 

[Ole'Lefty]

NO- the bass "E" string should be longer than the treble"E"( sometimes as much as 3/32nd")- measure from front of nut to center of 12 fret-double it. Then take that number and go to S-Mc free info and the Fretboard/scale calculator- it will tell you the compensation that should be there (though I usually bump that up by at least .030). If your bridge isn't close then it is a real problem- I worry if you have done anything that would void your warranty.

 

[Spotcheck Billy]

Ltdave has posted an excellent bridge locating technique. That might help you a bit. Find it here http://www.mylespaul.com/forums/luthiers-corner/224735-intonation-whats-fuss.html

 

[Jim_E]

First determine the scale length by measuring from the face of the nut to center of the 12th fret and doubling that measurement.

You should have the full scale length from the face of the nut to the treble side E string saddle when it's in the middle of it's adjustment.

You should have that same amount plus at least .125" more on the bass E string side from the face of the nut to the center of the E string saddle when it's in the middle of it's adjustment.

 

[Ole'Lefty]

#8??

 

[Tonemeister]

According to Gibson the scale length is supposed to be 24 3/4". I get 12 1/4" from nut to 12th fret. That would mean the scale is 24 1/2". My measurement from nut to center of bridge post is 24 11/16" (1/16" shy of 24 3/4") So my distance from nut to 12th is shorter than 12th to bridge (treble side). This seems consistent with my problem of not being able to bring the saddle forward far enough. Notes are flat at the 12th fret compared to the open. I guess because when you fret the note the length is longer than half of the string.

 

[Tonemeister]

I worry if you have done anything that would void your warranty.

me too. All I did though was swap out to a roller bridge. I could put the old one back and one would never know. I did put some teflon tape on the posts because they were kind of wiggly ( nothing major) and I widened the nuts slots.

 

[Clyngedal]

Exactly, you widened the nut slots.. Which is non-reversable :/

 

[Tonemeister]

Understood but one would hope that Gibson would own up to the bridge placement issue since that has nothing to do with the nut. I'm not complaining about the nut even though it was poorly cut.

My question is are the above mentioned measurements cause for alarm? Do they warrant a claim?

 

[Ole'Lefty]

Typically Gibsons come out to one of three "actual scale lengths. Imperial+ 24 9/16th", 24 5/8th" and then a leap to actual 24 3/4" supposedly to the center of the travel space of the "middle" saddle. Unless it is a custom shop or Historic or those $$$$$$$ factory LP's one usually will see the shorter actual measured scales. Did you follow my directions on measuring and did you then do a mathematical scale computation. Now the mathematical result usually needs to be massaged somewhat with "compensation." The common bridge that delivers more saddle travel is the Nashville. I have done installation by math BUT I always fudge and set the treble post longer by 2-3 /32nds" and not unusual to see an honest but frightening stout 3/16" set back for the bass post. ( "Stout" is a rural term for big, significant, strong). The odds of stretching it out way too much aren't that great if you don't get ridiculous about it. If your treble "E" saddle was all the way forward and iffy and then the bass "E" saddle was all the way back, and iffy, that is some real crazy bridge installation.

I trust ltdave32's math way to set a bridge and some of us have trapeze tailpieces that we use to empirically position the bridge so it will be within intonation range because the centerpunch for drilling the posts guarantees compensated installation ( on centerline too). I like it because I have had tolerance stackup that did force me to push the limits of saddle position. My fault- should have measured better first and thought about it for a long time before stepping on the drillpress pedal (deadman switch- a good drillpress safety item and reduces contortions lining things up.).

Before you do anything more, really think through these options and ponder that if a guitar store sold me "as truly new" the guitar that you screwed around with, then headstock breakage will reveal its cause by residue and odor from the salesman and you, if I could find you.

 

[Tonemeister]

Typically Gibsons come out to one of three "actual scale lengths. Imperial+ 24 9/16th", 24 5/8th" and then a leap to actual 24 3/4" supposedly to the center of the travel space of the "middle" saddle. Unless it is a custom shop or Historic or those $$$$$$$ factory LP's one usually will see the shorter actual measured scales. Did you follow my directions on measuring and did you then do a mathematical scale computation. Now the mathematical result usually needs to be massaged somewhat with "compensation." The common bridge that delivers more saddle travel is the Nashville. I have done installation by math BUT I always fudge and set the treble post longer by 2-3 /32nds" and not unusual to see an honest but frightening stout 3/16" set back for the bass post. ( "Stout" is a rural term for big, significant, strong). The odds of stretching it out way too much aren't that great if you don't get ridiculous about it. If your treble "E" saddle was all the way forward and iffy and then the bass "E" saddle was all the way back, and iffy, that is some real crazy bridge installation.

I trust ltdave32's math way to set a bridge and some of us have trapeze tailpieces that we use to empirically position the bridge so it will be within intonation range because the centerpunch for drilling the posts guarantees compensated installation ( on centerline too). I like it because I have had tolerance stackup that did force me to push the limits of saddle position. My fault- should have measured better first and thought about it for a long time before stepping on the drillpress pedal (deadman switch- a good drillpress safety item and reduces contortions lining things up.).

Before you do anything more, really think through these options and ponder that if a guitar store sold me "as truly new" the guitar that you screwed around with, then headstock breakage will reveal its cause by residue and odor from the salesman and you, if I could find you.

I do enjoy a nice "Stout" every now and then. In South Boston, where I live, Guinness is the Stout of choice, but I catch your meaning. I must admit I've been working some crazy hours and by the time I've gotten to take my measurements it is about 3am EST (as evidenced by my post times. Ugh) In any event, I hope to really follow your instructions and check the calculations. I read over "ltdave32"'s post and according to his formula I would need to double the (12 1/4" which is what I get from nut to 12th fret.) Then subtract 5/32" to get my treble side post measurement. That would give me 24 11/32". I measured 24 11/16" on my guitar from the nut to a line parallel to the center of the treble side bridge post. That is exactly 11/32" further back than what "ltdave32" suggests. What do you take from that? I'll test out further tonight after checking your post again.

 

[LtDave32]

Ltdave has posted an excellent bridge locating technique. That might help you a bit. Find it here http://www.mylespaul.com/forums/luthiers-corner/224735-intonation-whats-fuss.html

NOTE TO THOSE WHO WISH TO USE MY BRIDGE SETTING METHOD:

I wrote the numbers down wrong. It should be:

1/16" OVER the line on the TREBLE side,

and 5/32" UNDER the line on the BASS side..

Sorry for the mix-up.

Still, this is the way Gibson Authorized Factory Service Centers do it, and it works. Since taught this method, I've used it on every build, and every time it's come out right on the money.

 

[LtDave32]

Typically Gibsons come out to one of three "actual scale lengths. Imperial+ 24 9/16th", 24 5/8th" and then a leap to actual 24 3/4" supposedly to the center of the travel space of the "middle" saddle. Unless it is a custom shop or Historic or those $$$$$$$ factory LP's one usually will see the shorter actual measured scales. Did you follow my directions on measuring and did you then do a mathematical scale computation. Now the mathematical result usually needs to be massaged somewhat with "compensation." The common bridge that delivers more saddle travel is the Nashville. I have done installation by math BUT I always fudge and set the treble post longer by 2-3 /32nds" and not unusual to see an honest but frightening stout 3/16" set back for the bass post. ( "Stout" is a rural term for big, significant, strong). The odds of stretching it out way too much aren't that great if you don't get ridiculous about it. If your treble "E" saddle was all the way forward and iffy and then the bass "E" saddle was all the way back, and iffy, that is some real crazy bridge installation.

I trust ltdave32's math way to set a bridge and some of us have trapeze tailpieces that we use to empirically position the bridge so it will be within intonation range because the centerpunch for drilling the posts guarantees compensated installation ( on centerline too). I like it because I have had tolerance stackup that did force me to push the limits of saddle position. My fault- should have measured better first and thought about it for a long time before stepping on the drillpress pedal (deadman switch- a good drillpress safety item and reduces contortions lining things up.).

Before you do anything more, really think through these options and ponder that if a guitar store sold me "as truly new" the guitar that you screwed around with, then headstock breakage will reveal its cause by residue and odor from the salesman and you, if I could find you.

Lefty, on wrap-tail bridges, don't forget this:

1) Measure the diameter of the tailpiece stud, and cut that measurement in half. Add that half-measurement to the angled, final bridge line. This is where the drill point goes.

2) Because of the angle, the strings will flop over to the treble side of their holes. this will cause the strings to not lay dead-center over the pup pole pieces. Simply shift the final positioning of drilling the studs to the bass side 1/16" (for both studs). This will result in the strings being perfectly aligned over the pole pieces.


I vow to do a picture tutorial on this, for I have a wrap-tail build coming up soon. The same positioning and "angle finding" applies to ABR/adjustable bridges as well, with the only difference being not moving the whole affair over 1/16" to compensate for the strings flopping over. They stay in their saddles on adjustable bridges.

 

[Spotcheck Billy]

I vow to do a picture tutorial on this, for I have a wrap-tail build coming up soon.

I, for one, would be anxious that follow that tutorial. Bring it on!