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View Full Version : Vintage Bridge Placement - Wrong from the start



Bazz Jass
Jun-11-2021, 7:02am
It's been my observation that the bridge of a vintage Gibson oval hole has to be well south of the pickguard to intonate correctly, and inevitably there is an indentation of where the bridge used to rest.

I first encountered this in the 90s, with a band members mid teens F4. The type where the pickguard has a pin that goes into the hole in the bridge. To intonate even close to being in tune at the octave, the bridge had to be so far south of the pickguard that the pin cleared the hole completely.

I see the same with my own F4, and many others listed. Exhibit A - bridge well clear of the pickguard, marks on top from original position:

194641

Exhibit B - bridge is flipped so that it doesn't have to be so far south of the guard:

194642

Curious to know why the bridges were originally placed wrong by today's standards - guessing different string tension or something?

With a bridge in original position, hard against the guard, these instruments play completely out of tune with modern strings.

Hendrik Ahrend
Jun-14-2021, 8:37am
Jass, please allow to suggest to never trust the "original" bridge position. A mandolin may have been set up incorrectly from scratch, but may just as well have changed/moved a bit from the permanent tension over the years; one may call that phenomenon "bridge creep". Also, a good number of Gibson fretboards had mal positioned "off" frets originally. Hence, Chris Thile did not keep his original fret board on his first Loar F5. (Believe his second Loar underwent the same treatment.)

Turning the bridge top around should have the opposite effect on intonation BTW, that is moving the bridge further up. (I wonder what's the story in Exhibit B.) Also, turning around the bridge top should screw up the string spacing, which gets usually wider towards the bass strings.


IMHO (and from about 45 years of experience in playing and set-up work), the bridge has to be in the "right" position, if you want good intonation. The first notes to be checked would be the octaves, but 7th fret positions are also interesting. A compromise may be necessary. Fortunately our ears are quite forgiving.

Don't worry about the position of the pick guard towards the bridge and have fun picking.:)

jimmy powells
Jun-15-2021, 4:50am
I don't think string tension/modern strings comes into this. The pickguard 'pin' which goes through the bridge may have seemed appropriate at the time but I dare say some of them were maybe slightly out of place, causing them to be short. It was the 'design of the time' but would have been improved with a longer pin rather than a longer pickguard.

Mandolin bridges out of position has been a constant occurrence in the hundreds I've handled. Not a problem, apart form the obvious colour issue whereby a bridge has been on for 50 years or more and when placed correctly, there is a line showing a lighter colour. A little annoying in what can often be an otherwise beautiful top.

Bazz Jass
Jun-15-2021, 3:11pm
I often wonder how a mandolin bridge could be in the wrong place for so many (up to 100) years. I guess a lot of owners never played past the fifth fret?

Shifting the bridge to the correct position seems like about the easiest home adjustment one could make!

:whistling:

MikeEdgerton
Jun-16-2021, 10:57am
You're assuming two things. That the instrument was played and that the player knew it was out of tune. I can assure you that even in this day and age of electronic tuners you still run into people playing out of tune instruments that don't know the instrument is out of tune. Go to any bluegrass jam and stand on the fringes. You'll find them :)

Bazz Jass
Jun-16-2021, 2:50pm
You're assuming two things. That the instrument was played and that the player knew it was out of tune. I can assure you that even in this day and age of electronic tuners you still run into people playing out of tune instruments that don't know the instrument is out of tune. Go to any bluegrass jam and stand on the fringes. You'll find them :)

lol! You bet :) Given those old vintage Gibson tuning head gear ratios, and lack of electronic tuning help, it becomes clear there must have been MANY out of tune Gibson mandolins....

Hendrik Ahrend
Jun-17-2021, 11:36am
Be careful, "those old vintage Gibson tuning" machines (Waverly actually) work perfectly well on my two vintage Gibsons. Just sayin' :)

HoGo
Jun-18-2021, 1:18am
I'd say many folks used light strings and didn't play much above 7th fret so they didn't feel the need to adjust the bridge to perfection (even though the Gibson brochures described the process AFAIK)

Hendrik Ahrend
Jun-18-2021, 7:51am
... even though the Gibson brochures described the process AFAIK) They did well, e. g. in the 1923 Handbook.

Bazz Jass
Jun-30-2021, 3:58am
Just had a quick look at the catalog from the day.

https://acousticmusic.org/wp-content/uploads/2016/02/Gibson-1921-Catalog-M.pdf

Every mandolin image shows the bridge hard against the pickguard. This couldn't have intonated properly with today's strings. Without exception, every "in tune" teens/early twenties Gibson oval hole mandolin I've encountered has had the bridge moved away from the guard. Generally exposing marks in the finish where the bridge had been hard against the edge of the guard as shown in the catalog.

194944

194945