strange question

[Marc Piane]

How much can you let out adjusters (raise) before you run out of threads and run the risk of bridge problems?

[George700DL]

Originally Posted by fingers

How much can you let out adjusters (raise) before you run out of threads and run the risk of bridge problems?

The rule I go by is at least 1/2 the threads in the wood. But I have OCD.

George

[Uncletoad]

The threads on my Cleveland have been out a centimeter for years, which I'm sure is more than half way and everything is fine. I'm not sure how much is left inside, perhaps 5mm or so.

[Marc Piane]

Cool. I'm prolly in the centimeter range myself.

[sjd007]

I installed adjusters last year and from memory the thread is about an inch long, so a centimeter or so should be fine. I imagine most adjusters would be similar dimensions...

Simon

[Chris Fitzgerald]

I ran into this issue a few years back, and it got to the point where I was getting nervous about how high they were jacked up. Eventually (also OCD) I took the bass in to Nnick and he agreed that they were borderline, so he made a shim/extension for the upper part of the bridge and drilled it for the adjusters. No problems since.

[George700DL]

Originally Posted by sjd007

I installed adjusters last year and from memory the thread is about an inch long, so a centimeter or so should be fine. I imagine most adjusters would be similar dimensions...

Simon

The single piece aluminum ones I installed definitely have 1 inch of thread on them, so 1 cm exposed is no biggie. That's about where I'm at.

George

[swingingoodtime]

Originally Posted by fingers

How much can you let out adjusters (raise) before you run out of threads and run the risk of bridge problems?

Hard to say without taking the bridge off, but with your adjusters all the way down (ie with the bridge at its lowest), your adjuster threads can extend no further than the depth of the bridge foot on each side, so that distance, less about 5mm for stability's sake, is the absolute maximum you could ever go ASSUMING that the tip of the thread does in fact almost touch the belly under the aforementioned condition. So maybe be conservative & subtract another 5-10mm again if your foot seems particularly tall? Maybe check the average thread length of commercial designs, too.

[George700DL]

Originally Posted by swingingoodtime

Hard to say without taking the bridge off, but with your adjusters all the way down (ie with the bridge at its lowest), your adjuster threads can extend no further than the depth of the bridge foot on each side, so that distance, less about 5mm for stability's sake, is the absolute maximum you could ever go ASSUMING that the tip of the thread does in fact almost touch the belly under the aforementioned condition. So maybe be conservative & subtract another 5-10mm again if your foot seems particularly tall? Maybe check the average thread length of commercial designs, too.

There is no way to make any assumptions about what's inside the foot, other then the very likelihood that the threaded part of the adjuster is 1 inch, or 2.54cm. You need way more than 5mm of thread inside the foot, otherwise you're running a pretty good risk of the top of the bridge breaking off.

I personally wouldn't go out more than 16 mm or so max, and preferably less. If you're not sure, you can always take the strings off and take out the adjusters to see how much thread there is.

George

[robobass]

It ain't how much thread you see, but how much you don't see that is important!

[Uncletoad]

Originally Posted by robobass

It ain't how much thread you see, but how much you don't see that is important!

Exactly!

[sjd007]

Indeed.

I installed my adjusters with the thread upwards (into the bridge) and the little knobs down (into the feet) so the comments about the height of the feet being the maximum length of the thread doesn't apply to me (or anyone with adjusters installed this way).

I also drilled 6 holes around the "dial" to reduce mass. Not sure if it makes any difference to the sound (theoretically it should), but it sure looks pretty!

Simon

[swingingoodtime]

Originally Posted by George700DL

There is no way to make any assumptions about what's inside the foot, other then the very likelihood that the threaded part of the adjuster is 1 inch, or 2.54cm.

But my point is that there's an absolute maximum that the thread could theoretically be, and if the combined thickness of the foot and the adjuster wheel is LESS than 1 inch, then the amount of available thread must be less than 1 inch too. Going by this, your statement above is in itself a dangerous assumption to make. If it's more than 1 inch, then sure, I absolutely agree that what you can't see is what you can't see, but I wasn't suggesting that the OP definitely run with that maximum length. Hey, I did encourage conservatism…

You need way more than 5mm of thread inside the foot, otherwise you're running a pretty good risk of the top of the bridge breaking off. I personally wouldn't go out more than 16 mm or so max, and preferably less.

Not sure what you mean by 'breaking'; if you mean sliding laterally/sideways so the the main bridge section falls off the top of the foot, then 5mm should be more than sufficient to prevent this. If you mean preventing the upper section of the bridge from tilting to the point of the whole thing collapsing: your bridge simply shouldn't be at that angle to begin with; ideally, the bridge should be perpendicular to the bass belly and the forces should be running vertically through the adjuster into the top, with no horizontal force component. But assuming real world conditions where a small amount of tilt will likely occur (say, 5 degrees), 5mm should be enough to account for this (but no, I wouldn't go any less than this either).

Incidentally, if the 1 inch thread length you're referring to is the absolute length, (ie, not just the amount exposed with the adjuster wheel wound in fully), then, taking the thickness of the adjuster wheel in account and going by my adjuster wheels' thickness of 5mm which I'm assuming (!!) is pretty much standard from what I've seen, at the 16mm max you mention, you've got 4-5mm in the bridge foot.

If you're not sure, you can always take the strings off and take out the adjusters to see how much thread there is.

Totally agree with you on that!

[George700DL]

Originally Posted by swingingoodtime

Not sure what you mean by 'breaking'; if you mean sliding laterally/sideways so the the main bridge section falls off the top of the foot, then 5mm should be more than sufficient to prevent this. If you mean preventing the upper section of the bridge from tilting to the point of the whole thing collapsing: your bridge simply shouldn't be at that angle to begin with; ideally, the bridge should be perpendicular to the bass belly and the forces should be running vertically through the adjuster into the top, with no horizontal force component. But assuming real world conditions where a small amount of tilt will likely occur (say, 5 degrees), 5mm should be enough to account for this (but no, I wouldn't go any less than this either).

I mean that with only five mm in the foot, there is a pretty good lever action going against your interests, and I am not willing to take chances with that. It could be OCD speaking.

Originally Posted by swingingoodtime

Incidentally, if the 1 inch thread length you're referring to is the absolute length, (ie, not just the amount exposed with the adjuster wheel wound in fully), then, taking the thickness of the adjuster wheel in account and going by my adjuster wheels' thickness of 5mm which I'm assuming (!!) is pretty much standard from what I've seen, at the 16mm max you mention, you've got 4-5mm in the bridge !

The 2.54cm is the length of only the threaded part. So if 16mm of the thread is visible, it means that 9.4mm of the thread is in the foot. A mm here or there is not the end of the world, but I keep my adjusters no more than half of the thread out - meaning around 12 or 13 mm.

There are people with way more experience than me who recommend, as a general rule, at least 1/2 of the thread in the foot. I think there are good reasons for that. I fitted a grand total of 1 pair of adjusters, and it took long enough for me to not want to repeat that process any time soon

George

[Jake deVilliers]

Hey now fellas, the problem is that as you get more of your allotted one inch of aluminium threads rising out of the foot of the bridge, there are less and less fragile wooden threads supporting the downward pressure of the strings.

Some bridges might support that pressure with 5/8 of an inch of adjuster threads sticking out, some might not. It depends on the hardness of that piece of wood and also on the size of the pilot hole drilled before tapping.

You kinda have to ask yourself "Do I feel lucky?"

[Matthew Tucker]

if your adjusters look like this its probably OK



... but if you want MORE, it's time to have the bridge seen to by a bass bridge podiatrist.

[Chris Fitzgerald]

Originally Posted by Matthew Tucker

if your adjusters look like this its probably OK



... but if you want MORE, it's time to have the bridge seen to by a bass bridge podiatrist.

Exactly where I was, hence Ddr. Nnick!

[Matthew Tucker]

Same bridge after treatment, set even higher but with maple added to the tops of the feet.



This was an existing bridge; i didn't fit or shape the original feet. They were ugly so I reshaped them a little. The black muck on the E foot is ebony dust from you-know-what.

[George700DL]

Originally Posted by Matthew Tucker

The black muck on the E foot is ebony dust from you-know-what.

That's OK Matthew, my E foot is showing traces of bright red lipstick from you-know-what.

George

[Jake deVilliers]

Originally Posted by George700DL

That's OK Matthew, my E foot is showing traces of bright red lipstick from you-know-what.

George