Jag Jazzmaster Mustang bridge - a thought

[kurski]

Hi all

I just came up with a thought, what if both poles that go to the mouting holes had spherical shape on their tips done to the same diameter that the holes themselves. Anyone thinks this is a good idea to eliminate the stability problems?

[Danley]

Do you mean - instead of the two pointed adjustable screws, a sphere on each pole? When you say instability are you saying your bridge is easily shoved back or forward from center? Not sure what that would accomplish other than more friction at the point where the bridge rocks. I don’t have any problem on any of my half-dozen current Mustangs/Jaguars/Jazzmasters with the bridge not keeping on-center. When I have run into that problem before, it has been on guitars with something crazy going on with the neck angle (btw- only one of my offsets needs a neck shim, all others are shim-less.)

[kurski]

What I mean is: make the end of the shaft to have a sphere on the tip so it still rocks backwards and forward like Leo originally thought but gives it a tight fit. Black screw is still there for height adjustment and the tension it creates against the bottom of the ferrule helps the bridge to come back to the upright position. I can post a drawing if you have difficulties in understanding what I mean. I am surprised nobody thought of this as a ball joint is the best design in engineering when it comes to movement and stability... much like ball joint design in automobile applications

[601210]

Doesn't that just increase friction?

[Danley]

If it was like a ‘self-centering joystick,’ a ball joint might be a bit overkill in that the bridge need only move forward/back - at the same time, it would need the complexity of a self-centering mechanism (which is not a given in automotive ball joints.)

I think part of the beauty of the rocking bridge is its simplicity- engineer out the simplicity and you might as well go with a roller bridge. On top of that (like I mentioned,) although I understand some people have an issue with the bridge sliding around, I do not - or I should say, that problem went away once I just set the guitar up properly.

Last point- Fender also makes nylon bushings that self-center the bridge while not inhibiting the rocking; not really a very engineered solution but apparently effective for those who do have the problem. Points for creativity to you though!

[kurski]

friction of what against what?

[kurski]

I almost agree but... roller bridge does not move while a Fender bridge moves and this changes the intonation thus affects the sound. Also car’s ball joint does not self level i agree but the spring tension of the height strut should do it by itself. I tell you what, I will get a prototype machined and see if it works Then I will sell it to you for shait loads of chips

[Horsefeather]

Do the conventional pointed tips even move around in their cups? I didn't know that was a problem. I know it's not for my Jazzmaster.

[kurski]

My bridge always moves ever so slightly sometimes causing the strings to buzz against intonation screws.

[Horsefeather]

So are the bottoms of the thimbles flat on the inside? I assumed they're funnel shaped (like an inverted cone) to keep the point of the bridge post centered but I haven't been able to find anything actually depicting that.

[Danley]

I’m 90% sure most are coned. I *think* I know the issue he’s talking about, where the bridge rocks too easily when palm-muting etc. and sticks forward/back. At risk of repeating myself again, I don’t have any guitars where that’s an issue (and one of my Jazzmasters is presently in drop D for doom chugging.)

[Horsefeather]

Okay, so the problem we're talking about is not that the bridge posts slide around in the thimbles, rather that the bridge rocks in its intended motion but in such a way that the saddles slide out from under the strings and the bridge ends up stuck in either the forward or backward position?

I've thought about that myself, actually. Not because it's much of a problem for me but simply because I've thought a lot about the goofy nature of this design and how it could be improved. I envisioned some kind of saddles where the string actually gets clamped between two halves so that string and saddle become one assembly. But that's silly because it would probably be bulky and people like access to the tops of the strings for muting.

At the end of each brainstorm is always the same conclusion: The Jazzmaster, Jaguar, and Mustang should have roller saddles. Sitting in a fixed bridge. The only reason it's not currently a slam dunk to make that conversion is that there aren't any TOM-type bridges with the right radius.

But returning to your idea, I think you could achieve a similar effect by slipping a rubber o-ring or two around the bottoms of your posts so that whenever it rocks off center it has to compress them. It would keep them centered pretty well, I bet. And it sounds like that's what Fender provides somewhere, based off Danley's previous post.

[timtam]

The vintage style bridge is designed to 'grip' the strings and rock unimpeded fully forward and backwards as the strings move with trem action. It requires high friction between the string and saddles to achieve this gripping. It achieves the guided rocking on frictionless conical bearings (the conical tips of the bridge height grub screws) sitting in the reverse-conical bottoms of the thimbles. Leo's patent describes all this clearly. Any failure or impediment to this mechanism during trem use results in the bridge not returning to the position it started from, with resulting disordered tuning.

Locking saddles that fix the strings to the saddles would theoretically improve the rocking mechanism, by preventing any sliding of the strings interrupting the require continuous string gripping. The interface between the cone-tipped bridge height screws and the thimble bottoms must remain as near to frictionless as possible.

A fixed, non-rocking bridge requires the opposite to the vintage design - low friction saddles that allow the strings to slide smoothly back and forth over them with trem action.

[kurski]

This is what I'am on about. Tight fit but still rocks back and forward.

image hosting

[jorri]

That introduces more friction. The strings usually give friction problems and that would be two competing friction problems.

However, perhaps we have two different stability problems. Before i changed bridges, the bridge would rock back too freely then get stuck lent toward the neck. I put graphite on the saddles and it became even worse! Now it is hard to push, requiring a bit of force, so i think there is some tuning stability lacking.... This seems to be because there is more friction between string and saddle groove.

Imho a spring mechanism would be better. I dont know the best way to do that, so an engineer can say where to put a spring, or two opposite springs. The problem with that is then string friction must overcome the spring force, so that the bridge rocks, so idk if that would work.

Other stability issues is mostly the screws becoming loose. Or the buzz of moving saddles. Loctite and some different shaped saddles would be the solution (see badass bass bridge vs original bass bridge, they already fixed that on a similar bridge)