Adjusters with uneven top

[mheintz]

If the top of the bass is uneven such that the G-side foot is significantly lower than the E-side foot and an adjustable bridge is installed on the bass, where should the extra height necessary to make the bridge even be? Is it in the top of the foot, the bottom of the foot or the arch or would the G-side adjuster have more threads exposed?

On a related note, would premade adjustable bridges generally have the adjusters installed correctly for a bass with an uneven top? In other words, one could modify the bottom of the foot, the arch or adjust the threads, as the case may be, because you couldn't modify the top of the G-side foot.

[fdeck]

Is it possible that the bridge is in there backwards?

A premade adjustable bridge has to be fitted to the bass. The feet are shaped to fit the belly of the bass and the top is shaped for the desired string heights. Presumably this work is done with an equal spacing on the adjusters, so the two are the same spacing when the job is done.

[mheintz]

Thanks for the response. I'm not asking with respect to my bridge.

I was just reading Traeger's instructions on installing an adjustable bridge and I'm trying to envision how premade adjustable bridges (e.g., Kolstein) come up with the same result on an uneven top as a fixed bridge that is custom fitted with adjusters. If I'm understanding Traeger correctly, he fits a bridge without adjusters and to find the top of the adjusters, he draws a line parallel to the top measuring from the edge of the top. If the G side were a bit sunken relative to the edge of the top compared to the E side, then it seems to me that the G foot would either need to be taller (either at the bottom or top) or there would need to be more threads visible on the G foot. Assuming that the same amount of threads are visible on the E and G side, then the bottom of the G foot must either be thicker or the top of the G foot must be thicker. As I understand it, for premade adjustable bridges, only the thickness of the bottom part of the foot is reduced when fitting the bridge.

I may have this all backwards. At the end of the day, I'm wondering if the premade Bridges (e.g., Kolstein) can really achieve the same fit (if not the same result) as custom-installed adjustable bridges on basses with irregular arches or sunken tops.

[fdeck]

Aha, now I understand. And I would not mind knowing the answer too. My bass certainly falls in the "uneven top" category. I fit the bridge before cutting it apart to install the adjusters a few years later. And I came up with what I thought was a good trick for making the gaps flat and parallel with the holes all lined up nicely, but I have no idea of the mainstream technique.

[forester]

you are on the right track... a premade setup will address most irregularities as is..the fitment normally made at the bottom of the feet.since the sizing has been predetirmined you sacrifice the eveness you desire by compensating in either threadlength of the adj. or the thickness of foot to square the bridge with a significant drop on the treble side as you describe. if you want even threadlength/even foot thickness you would have to shorten the (leg) on the bass side (that predetirmined thing)but..now you have to deal with the installed thread (did they put it in the foot? or the bridge?) either way you have to make amends for molesting it. an uncut bridge can be sized to compensate on the treble side by leaving additional length on the leg when installing adj.

normal disclaimer applies:

[mheintz]

Thank you, forester. Very helpful.

[Matthew Tucker]

Originally Posted by mheintz

I was just reading Traeger's instructions on installing an adjustable bridge and I'm trying to envision how premade adjustable bridges (e.g., Kolstein) come up with the same result on an uneven top

I think the thing you have to remember is that Traeger's book only shows how HE or his colleagues do things. And he's very clear and up-front about that. He does not show the ONLY way to do things (and some might claim not even necessarily the BEST way)

I have no issue with his book at all, it's a useful reference to look at when planning any bass work, and a lot of what he says is valid and useful, and sometimes thought-provoking ... but just don't use it as a bible.

Cutting a bridge with uneven legs to compensate is just one approach. Widing up one adjuster way more than the other is another. Another approach might be to try to restore the arching to where it "should" be ... I think that in the end, you have to decide what's important to you and what your budget will stand.

Every luthier has their own personal preferences, and that's what sets them apart from each other. You go to the luthier you trust.

[mheintz]

Good point. Thanks MT.