Bridge placement

[john09121]

I've noticed recently that my e string was too close to the edge of the finger board, so my hand would occasionally mute it when I played up the neck. To fix the problem, I loosened up the string and pushed the bridge over a few mm to the left (if you're facing the front of the instrument), and made it so the G string and E string each had equal space from the edge of the fret board. Strangely, after I've made this adjustment, I've found that the bridge is now closer to the left f-hole than it is to the right, despite the fact that the strings are centered on the fret board. What's more, though I could definitely be imagining things, there seems to be a slight drop in tone quality.

Could this mean that my neck is warped? It seems unlikely since I bought the instrument (an F5-G) new less than a year ago. I'd be very disappointed if this were the case because I love this mando!

I know I should be comparing the harmonic to the fretted note at the 12th fret when I'm adjusting in the dimension parallel with the strings. But what about the dimension perpendicular to them? Should it be centered? Or is it normal to have the bridge slightly to one side?

I'll try to post some pictures as soon as I have access to a camera.

Thank you!!

[Markelberry]

Don't know that I am qualified but,when the bridges on my mandolins are placed correctly the distance from the feet to sound hole treble or bass is fairly equal to that of the fingerboard,meaning they all pretty well alighn. If your s does not I would take it to a qualified shop for a pro opinion.

[fumblfingers]

I am a Newby but could the tail piece be out of alignment?

[Dale Ludewig]

Twelfth fret harmonic to fretted note: that's right. Side to side, you are doing fine. The strings should be centered left to right on the fingerboard. If you're pulling the string off the side of the board or having other problems because it's too close to the edge, well that's no fun. I wouldn't worry about if the bridge is slightly closer to one f-hole than the other. If the action is all fine up and down the neck, I would doubt that it's warped. It wouldn't hurt to take it to a good luthier.

[Pete Summers]

I wouldn't worry about the lateral position of the bridge if the intonation is correct and the strings centered on the fret board.

I have had many fiddles over the years where the bridge set slightly closer to one f hole than the other. That's not uncommon on factory made instruments where the position and shape of f holes is not precisely cut, or the tailpiece is slightly off center.

In fact, I have a Gretsch mandolin where the neck is mounted slightly off dead center to the body, making the bridge slightly closer to the left f hole. The strings, bridge and tailpiece line up though, and it plays and sounds great.

I think these kinds of flaws are fairly common and probably don't present a problem. I doubt you'd see this on a high dollar hand crafted mandolin, but sometimes the factory jobs are less than perfect in construction.

[EdHanrahan]

... I think these kinds of flaws are fairly common and probably don't present a problem. ... sometimes the factory jobs are less than perfect in construction.

Even the iconic Loar-signed Gibsons are known to be a bit asymmetrical in body & neck alignment; that has been discussed here extensively, though I'm not really qualified to comment further.

I recently found that my '94 Flatiron, somewhat similar to the F-5G, has the neck slightly misaligned, sending the G string over the edge despite re-centering the bridge every year or two. The "economical" solution, rather than re-setting the neck, will be to move the tailpiece about 1/8'' toward the treble side, even though it's now "properly" centered on the body. (Some might not approve of that, but...)

So the various "don't worry" comments above do seem reasonable to me. Hey, you're not alone!

What's more ... there seems to be a slight drop in tone quality.

It's possible (probable?) that re-aligning the bridge has moved it away from the portion of top-arch to which it had been fit, upsetting the bridge-to-top pressure. May need to have the foot re-set in its new position.

[john09121]

Thanks for all the feedback, guys. This community really blows me away every time I come here with a question. I've been advised to post some pictures, so I'll hopefully have those up by the end of the day.

It's possible (probable?) that re-aligning the bridge has moved it away from the portion of top-arch to which it had been fit, upsetting the bridge-to-top pressure. May need to have the foot re-set in its new position.

That was my first thought. Though, to the naked eye, the bridge appears to be pretty flush with the top. I live about two hours from Nashville and was considering bringing it to the Gibson factory. I'm really reluctant to return or replace it, because I've played other f5-gs and didn't like them nearly as much. I'm otherwise quite fond of this mandolin.

[avaldes]

Did you check the grooves on the bridge? Maybe they are not equally spaced and centered.
I think if you sight with one eye from the nut to the tailpiece, the strings should angle out slightly to the bridge, then in to the tailpiece. If this is not symmetric, it should be apparent.

[Tobin]

Sighting down the neck is tricky. With thicker strings on one side, action being perhaps higher on the bass side, and the bridge being cocked at a slight angle for correct intonation, it will create an optical illusion to where it looks lopsided when it may not be. Perhaps a more measured approach would be in order. Maybe a raised string line from center of nut to center of tail piece?

[Willie Poole]

If it was mine I would try a different bridge saddle with the slots cut to where the strings were all riding where they are supposed to all along the fingerboard, I have a mandolin that had the same problem but mine was on the G string, it slipped off of the finger board at times so I made a new saddle with the slots cut to allow the string to stay on the fingerboard...Not a big deal and also you can leave the bridge where it is supposed to be to get back to the sound you liked....

[EdHanrahan]

Yeah but... If you bought it new less than a year ago, it should still be under warranty (I assume that Gibson's is lifetime to the original owner?). It would be far better to have it "officially" corrected now, regardless of Gibson's specific remedy, than have a later and more serious warranty issue denied because of aftermarket modifications. Otherwise, what's the point of paying a premium for factory-new rather than one that's been gently used, and maybe de-bugged, for a few years?

Just a side note: I commented above that my Flatiron's neck was misaligned. I still find it hard to believe that I, or the folks that did the last set-up (a well-known shop in Brooklyn), never noticed that when the strings were properly aligned with the neck, the string pull between the bridge & tailpiece was blatantly unbalanced. Instead of the two outer and inner pairs forming symmetrical V's between the neck and the tailpiece (that is the A & Ds form a symmetrical V, while the Es and Gs form a wider V around them), the D strings actually angle slightly toward the Gs, forming a single offset V, while the Es & As angle more sharply toward the Ds than they should. I don't recall anyone here noting that issue before, at least since '07, but it could be worth verifying.

[Tobin]

Not to overanalyze the subject, but I would actually think that it would be ideal for the bridge to be slightly off-center. Since the tension is not the same on all four courses, having the bridge perfectly centered with mirrored break angles would lead to a net force that isn't balanced. The bridge would want to wander to one side over time until the opposing forces are balanced. I would think that if a mandolin were engineered to balance the resultant forces from the string angles at the bridge, it would have to be slightly off-center, and the neck would have to be realigned to follow it.

I doubt that's what's going on here, but I wonder if any luthiers have ever taken that into consideration.

[Ivan Kelsall]

Not to forget that the OP moved the bridge in the first instance because the E strings were too close to the edge of the fingerboard. After having moved it,he then found that the bridge was slightly more to one side than the other. As others have indicated,that's no big deal. It might simply indicate that the 'f' holes themselves might not be concentric about the lateral centre line. What's puzzling is that the tone has suffered if the bridge is now correctly positioned.
Willie has a good point & it might be a good idea to check that the bridge slots are = / = about the bridge centre & not a bit to one side. If they are to one side,i'd sand the bridge saddle carefully to remove the slots,mark them out correctly & re-cut them.It usually only takes a shallow groove to get the strings to stay in place,then they'll bed in over time & form their own groove - at least that happened when i fitted a flat CA bridge to a contoured f/board mandolin - i also had to sand the top to the correct contour. The bridge could then be repositioned back where it was,the saddle raised a bit to compensate for the sanding down & hopefully the original tone would reappear.
Our 'newbie' colleague "fumblfingers" might have a point as well - is the tailpiece pointing correctly up the centre line of the mandolin or is it off to one side ?. My very first 'cheapo' mandolin's t/piece was over to one side.The fixing holes were ok because when i fitted an Allen t/piece to it,it was fine. It was the tin t/piece that was twisted.
My bottom line though is that if the Mandolin is still under warranty,unless you want to try to correct any problem yourself,i'd contact Gibson & hope that Dave Harvey would take a look at your mandolin - that is if you're willing to do without it for a while.
Having read re.some of the results of Mr Harvey's care & attention,i'd go that way myself,
Ivan