Double Bass should i get a new bridge?

[jmpiwonka]

my bass is a shen SB200 willow (3/4 size).

i have a bridge from upton that has a span of 150mm, well i just measured it and it is 148mm now.
the outside edge of my bassbar sits only 66m from the centerline of my top plate.
i had adjusters installed recently, there are a few things i don't like....
1. the adusters are installed so that the threads go into the bridge towards the crown, they are not threaded into the feet like normal.
2. i wanted the guy to cut out very little wood so i could have the string height i wanted without the adjusters turned alot, i was left with a 4mm g string height with the adjusters down all the way and i wanted 6mm.
3. after i turned the adjusters to get my string height back now the bridge feet are just a little tilted towards the scroll, so they are not making full contact with the belly, pushing on the bridge crown only moves the top portion of the bridge on the adjsuters and the feet remain in the same position.
4. i also feel the bridge is a little thick too.

my main concern is the feet contact and position.
i could have the feet refitted a little, but i only wanted the adjusters to play with string heights and figure out where i like it, i don't plan on moving them now....i think i might go back to a solid bridge and just make sure the string heights are nailed.

so THE BIG QUESTION: the outside of the bridge foot sits at 72mm from the centerline of the belly currently.....the foot is 39mm long and 23mm wide...is this foot sitting over the bassbar???

the option i'm thinking about is ordering a despiau bridge from lemur with a 138mm span....do you think that is what i need to do?

 

[KSB - Ken Smith]

First, you have the Bass so just feel the Bar and see if it's under the foot of the edge of the Bridge.

Next, I have had Adjusters put in both ways. Each luthier has his idea what's best. I have never had a problem either way. What's done is done!

Now, it is winter, the Bridge adjusters should be up a bit. In the Summer, you will have to lower them when the back swells and the FB tilts slightly to the Top. At this time, you lower them to the desired height. There is no perfect height for a Bass. A Bass can move slightly at any time from heat, cold, humidity or lack of it.

Bridge too thick? It can still be thinned. If Upton made the Bridge for you, then call and discuss it with them. Pics would be good for them as well as us. It's easier to see the problem than read a bunch of numbers and try to make a decision.

 

[Eric Rene Roy]

sounds like our stock bridge...uncut...and we did not install the adjusters because a) we put threads down and b) we personally don't believe in selling unfit bridges with adjusters already in it. Unless you are the #1 best luthier in the whole universe, the feet just will never fit quite right.

jmpiwonka, when we cut a bridge, we thin the feet and sometimes trim the toes and heel a bit...depending on the geometry of the bass on the bench. The stock bridges we sell are a raw material. Various widths are available...but we find 150mm will fit most basses. Some need wide...and some need narrow. The Westover bass is being setup now and we just received a VERY wide bridge for it as the geometry of the bass is different than the "standard" bass we run across.

Wish you would have contacted us sooner...we could have exchanged the bridge before you started work on it.

 

[jmpiwonka]

eroy its not that big of a deal to me. i expected the luthier to recognize something like that and fix it.

the edge of the bridge foot does run past the bassbar about 6mm.

i live in texas ken, the temperature today was 87 degrees and the humidity is 41%....there is not much of a winter here, i think i was wearing short sleeves on christmas day.

i know the bridge can be thinned but, i'm wondering if the edge of the bridge foot should only extend to the end of the bassbar.
is this something that is fixed by ordering a narrower bridge or having a luthier cut the feet down?

 

[arnoldschnitzer]

The bridge foot should extend outward past the bass bar edge. Ideally the bass bar should sit just slightly outside the bridge leg. This is generally accepted practice, though some makers and shops do it differently.

 

[jmpiwonka]

The bridge foot should extend outward past the bass bar edge. Ideally the bass bar should sit just slightly outside the bridge leg. This is generally accepted practice, though some makers and shops do it differently.

so my foot extending past the bassbar a little is fine...the way it is now the centerpoint of the bridge foot should be still be sitting over the bassbar.
if thats the case i'll most likely just have the luthier see if he can fix the fit on the feet a little bit.
they are just tilting on the scroll side of the feet some, i could maybe slide a thin piece of paper under the edge (not very far under though), thats about the amount they are lifted.
like i said before trying to adjust the top of the bridge has no effect on the way the feet sit.

 

[peasandhoney]

have you changed strings lately? it could be that the bridge is fitted fine and that when pulling the strings up to tension, the bridge was pulled over alittle as well. if the gap is only on one side or the other (fingerboard side or tailpiece side, not right or left), it is often because of a tilt. i havent see the bridge, so i couldnt tell you what your bridge is doing this but i can tell you i see this in our shop all the time (atleast once a week if not more). any gaps under your feet are robbing you of tone and volume so it should be something taken care of soon. good luck.

 

[jmpiwonka]

i have changed strings quite a few times and there is enough graphite in the slots for me to be able to move the bridge crown back and forth a little even with the strings under full tension.....doing this has no effect on the position of the feet. i am not going to move the crown alot as i feel that is a good way to crack my bridge legs where the screws are threaded in.
the feet did fit real well before the adjusters were installed in my bridge....so basically moving the bridge angle back to straight used to work, but now that i have adjusers it does not.
it seems that the same flexibility that is letting me move the upper portion of the bridge and still have the feet tilt a little should allow the feet to sit flush on the belly whether the upper bridge is angled or not, that is not the case though.

 

[jmpiwonka]

The bridge foot should extend outward past the bass bar edge. Ideally the bass bar should sit just slightly outside the bridge leg. This is generally accepted practice, though some makers and shops do it differently.

arnold, thanks for the reply.
can you clarify this though, this reads like you forgot to put a "not" in there somewhere.

if the bassbar should sit outside of the outer most part of the bridge foot then i think a little narrower bridge is the best way to fix this......i'm gonna post some pics when i get home.

 

[jmpiwonka]

ok i took some pics.

 

[jmpiwonka]

this is atleast real close to where the bassbar runs along the top. where the ruler runs.

and there is one of the bridge profile, where i put the green line is where the center of the heart is in the bridge and that width is 15mm.

 

[bribass]

i have changed strings quite a few times and there is enough graphite in the slots for me to be able to move the bridge crown back and forth a little even with the strings under full tension.....doing this has no effect on the position of the feet. i am not going to move the crown alot as i feel that is a good way to crack my bridge legs where the screws are threaded in.
the feet did fit real well before the adjusters were installed in my bridge....so basically moving the bridge angle back to straight used to work, but now that i have adjusers it does not.
it seems that the same flexibility that is letting me move the upper portion of the bridge and still have the feet tilt a little should allow the feet to sit flush on the belly whether the upper bridge is angled or not, that is not the case though.

Often on bridges w/ adjusters there can be a little play or wiggle room of the crown or top part of the bridge towrds the scroll or the tailpiece. This is because the shaft of the adjuster that is not threaded (in your case in the bridge feet) can have a bit of lubricant or a bit of paper or some soft substance to act as a type of bushing so the adjuster can be turned. Most of the time this is in the crown side of the legs and not the feet so the crown is kind of floating on the non threaded part of the adjuster feet. I suppose it could be the same w/ the threaded side up. If this were the case and there IS some play , that could explain why the feet can have that gap while resting on the top even w/ the crown straight and perpendincular to the top. If there is no "play" and the crown cannot wiggle one way or the other, it could be that the threads were tapped at slightly the wrong angle. I'm no luthier, but I've done minor adjustments on my bridges for years regarding their angle.

I think I would try placing a soft weight over the sound post area to keep it from falling (Arnold S. uses a small sack of buckshot for this purpose) and loosen the strings enough so I could set the feet flush against the top and see if the crown can be pulled straight while keeping the feet flush. I would not take all the tension out of the strings. just enough to do this while be very careful not to move the feet side to side. (mark their position first w/ a grease pencil)
If the crown cannot be staightened while the feet stay flush (not enough play) then I would conclude that the angle of the threads that were drilled into the bridge feet was off.

Sound right to you Arnold?

Probably best to have a luthier try this operation for you.

BG

 

[jmpiwonka]

i'm thinking the adjusters were threaded at the wrong angle.
i could take it back to him and have him fine tune the feet, but i'm mainly wondering if a narrower bridge would make a benefit (now that you can see where the feet are and approximately where the bassbar runs).
if a narrower bridge would benefit i'll just have a new bridge cut with my preferred string spacing and string height.....i didn't know where i wanted when i had the bridge cut and the luthier made my g string too low and spacing way too wide.....so i had the adjusters installed and the bridge thinned a bit by a different luthier and now the feet are giving me a bit problems i guess. the bass DOES sound better now.

i did tilt the bridge to where it was definately angled towards the tailpiece but the feet stayed in the same position, i also took the bridge off and checked the fit of the adjuster shafts and they are tight

 

[jmpiwonka]

i guess i could angle sand the top of each bridge foot where the face of the adjuster sits......but that will be a pain in the butt to get right.

 

[arnoldschnitzer]

arnold, thanks for the reply.
can you clarify this though, this reads like you forgot to put a "not" in there somewhere.

if the bassbar should sit outside of the outer most part of the bridge foot then i think a little narrower bridge is the best way to fix this......i'm gonna post some pics when i get home.

JMP, you read my post backwards; the bridge foot extends OUTSIDE the bass bar edge. Your bridge appears to be sitting in the right place. However, the fit looks NG.

 

[jmpiwonka]

ok, thanks.
i'll have the luthier look at the feet when i get some time.

 

[KSB - Ken Smith]

When you sand anything, it is easy to roll the edges. Use a sharp luthiers type knife when you fit your next bridge. Also, leave a little more meat on the feet edges. The problem you have seems to be self inflicted.

 

[jmpiwonka]

lol, that problem is inflicted by the luthiers in town.......
i was *kinda* considering the idea of fitting one myself.....but then i have to go buy some files, some knifes, and some planers i guess...but it would be real satisfying to get it right.