Double Bass Adjuster threads - above or below?

C

CPike

May 28, 2005
344
9
5,031
Dallas, TX
#1
Hey folks,

I'm fitting a new bridge and am about to install adjusters. For years, most basses I have seen have the adjuster threads above the wheel, pointing toward up the strings - but lately I have seen more and more with the threads below, pointing toward the bass. Any luthiers or players out there have a strong opinion either way? Maybe I'll just do one of each, ha ha.

Thanks, Chris
 
#2
CPike said:
Hey folks,

I'm fitting a new bridge and am about to install adjusters. For years, most basses I have seen have the adjuster threads above the wheel, pointing toward up the strings - but lately I have seen more and more with the threads below, pointing toward the bass. Any luthiers or players out there have a strong opinion either way? Maybe I'll just do one of each, ha ha.

Thanks, Chris
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It's really one of those six of one or a half dozen of the other situations. If you were installing the Full Circle adjusters with the piezo elements in the wheel of the adjuster, there might be an acoustic reason to do it one way or the other, but with ordinary adjusters I don't see any significant acoustic or structural advantage of one way over the other. I usually install them with the threads ups, but only because I like the way they look.
 
#4
I have a theory about why down might be better, but it is just that a theory , so no hard evidence backing this one. So imagine that one day many years down the road your adjusters get really tight from years of wear or whatever and you really have to crank them, are you wanting to crank them up having to kind of pull on them or are gonna want to just turn them with the help of gravity.

Also to me it just seems intuitive to have the down so that right makes it lower and left raises it. just my thoughts on it, but it should be noted that Ive never used ones facing up.
 
#7
BEEF said:
With the threads facing down, wouldn't it be an easier repair if the threads were stripped?
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You would think so.. plugging and retapping a stripped thread doesn't really work that well in my experience.You can make a new foot for the bridge, but lining up the holes can be tricky.
The fact is as you raise the bridge the exposed part of the adjuster is the threaded section.The more of this threaded part showing ,the more it will rock and hence a chance for the bridge top to move or warp if the the threads are up.
 
#8
Mark Carlsen said:
IMHO a threads up bridge tends to warp sooner than threads down into the feet.It all depends on how well the threaded side is tapped and how tight or loose the post end of the adjuster is made.I think most of us out East do it threads down...
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Bill Merchant (NY) installed threads up adjusters on my bass in 1980 and the bridge is still straight as a straight arrow.
 
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#9
Mark Carlsen said:
You would think so.. plugging and retapping a stripped thread doesn't really work that well in my experience.You can make a new foot for the bridge, but lining up the holes can be tricky.
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One of the other luthiers here once suggested that stripped threads in bridges can be restored by building up the (stripped) thread area with several thick coats of super glue and then re-tapping the coated hole. I've tried this on several occasions and I've yet to have one come back with the new threads stripped again. It's sure a lot easier than plugging or making at new foot and the angle of the threaded hole is unchanged. Even in a worst case scenario, this method can keep you playing until you have time to have a new bridge fitted.
 
#10
Thanks to all for the valuable input. I, too, have a threads-up bridge with zero warp, and this bridge is going on 30 yrs old! At one point I thought perhaps the threads-down approach would lessen the twisting of the feet that occur when adjusting the height, since there is so much flat surface contact between the bridge foot and the adjuster wheel. When I raise and lower this bridge I need to keep one hand firmly clamped on the foot to eliminate the twist - even with said surface lubricated with graphite. Has this occurred to anyone else?

Chris
 
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#12
When I raise and lower this bridge I need to keep one hand firmly clamped on the foot to eliminate the twist - even with said surface lubricated with graphite. Has this occurred to anyone else?
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Yes it happens to me with my Upton adjusters (installed threads up). Some people put a swipe of rosin under the bass foot to stop it sliding.
 
#16
Zombie thread revival!

I was talking to a luthier the other day who said he likes to put the adjuster threads up because it makes it easy to measure the distance both sides are out, so it's easy to keep them lined up. I see here that many people feel strongly about going the other direction, but I don't see a ton of discussion of why (except maybe a hint that threads up might be more prone to warping, but a similar amount of anecdotal evidence to the contrary). I do like the idea of being able to measure that my bridge adjusters are set evenly.
 
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#17
Mark_T said:
Zombie thread revival!

I was talking to a luthier the other day who said he likes to put the adjuster threads up because it makes it easy to measure the distance both sides are out, so it's easy to keep them lined up. I see here that many people feel strongly about going the other direction, but I don't see a ton of discussion of why (except maybe a hint that threads up might be more prone to warping, but a similar amount of anecdotal evidence to the contrary). I do like the idea of being able to measure that my bridge adjusters are set evenly.
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Haha...my threads up adjusters bridge (above) is still straight and fine after 45 years! I've always had threads up on my basses so that's what I'm used to.
 
#18
Eric Hochberg said:
Haha...my threads up adjusters bridge (above) is still straight and fine after 45 years! I've always had threads up on my basses so that's what I'm used to.
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I have always installed them threads up, and I do believe there are plenty of good reasons to do it that way. I think, however, that fully describing the reasons would be an onerous task, only of serious interest to a limited number of people, and also "poking a dead horse with a can of worms". So, here's just one reason:

Once you install the adjusters threads down, you have committed to a fixed, non-flexible relationship between the bridge feet, the adjusters, and the top of the bass. The only way to adjust the angle of the bridge is to re-cut the feet. Of course this can be done, but it takes time and is fussy. In contrast, with the threads up and a tiny bit of "play" in the (non-threaded) foot and adjuster relationship, the angle of the bridge is easily adjusted by changing the angle on the top of the foot.

All of the above describes when the bridge is first fitted. Over time, the bass top can change shape and then your bridge will shift from perpendicular. I see many basses that are played for years with a non-perpendicular bridge because of the fixed, non-flexible (threads down) method. Yes, you can adjust this, but only by re-cutting the bridge feet (if there's enough wood left to re-cut).

Disclaimer: This is not an attempt to open said can of worms. I don't have enough time to engage on a picayune discussion of this subject, and will 100% defer to people's right to make their own decisions (including making the wrong decisions!). :laugh:
 
#19
Mine is a bit of an oddball as I have two-part adjusters. The wheel is separate from the threaded stud. So obviously the visible threads are below the wheel, but the threaded part doesn't rotate.

I just realized the Full Circle I just ordered relies on at least one of the two bridge components having threads in the wood. I don't know whether my bridge feet are threaded! The adjusters I have would work the same with unthreaded holes in both sides. I may be running down to the auto parts store and getting a Heli-coil kit.
 
#20
I know some luthiers insist that threads down makes for a more precise install. I don't remember why exactly. My only opinion is that a Full Circle pickup sounds much better when installed threads up. All basses are different, of course, but I installed a FC threads down on a bass and it sounded 'okay'. Kinda thin and not very woody or powerful. Had the bridge changed to threads up and the FC sounded excellent. Fat, punchy and much woodier.
 
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