Jazzmaster String Breakage Theory

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Horsefeather
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Jazzmaster String Breakage Theory

Post by Horsefeather » Sun Feb 16, 2020 4:18 pm

I'm sure this has been discussed many times but I haven't found any definitive answers for the question why does it happen.

That is, after the protruding screw issue has been resolved.

I just broke my second high E in a very short period and I'm not bolting this thing back together (it's apart for other reasons) without a corrective measure in effect. I'm sick of dealing with all this JM bullshit. If I didn't love the tone so much I'd send it on down the river.

Anyway, this photo shows that the break occurred well back from the screw area and it's also clear of the hole where a burr might have acted upon it.

My theory is that the breakage is due to twisting forces. I think working the vibrato twists the string and wears it out. The string twists but the ball end doesn't so that point where mine broke becomes the stress area. That looks like a spiral type fracture to me, rather than a simple tension bust.

I suspect that the reason it happens to some guitars and not others is that it depends upon the alignment of the strings. Being the variable design that the stock bridge is, the line of the string north of the bridge is able to be pulled non-parallel with the line of the string between bridge and vibrato in increasing increments. I think the non-parallel arrangement might be what introduces twist.




Image


Then again, every Jazzmaster already has this non-parallel alignment built in, since the strings angle down from the bridge to the vibrato already.

However, the built-in break angle is probably not equivalent in its effect to the angle created by string spacing because the former follows the grooves while the latter pulls across them.

I also wonder if the fact that the bridge moves along with the string and is effectively locked to it rather than letting the string run across it with a roller contributes to the build up of torsion in the string. My Mustang conversion that uses roller saddles hasn't ever broken a string..

Anyone have any thoughts?



Image
Last edited by Horsefeather on Sun Feb 16, 2020 4:27 pm, edited 1 time in total.

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andy_tchp
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Re: Jazzmaster String Breakage Theory

Post by andy_tchp » Sun Feb 16, 2020 4:23 pm

Shit strings. Use something else.
"I don't know why we asked him to join the band 'cause the rest of us don't like country music all that much; we just like Graham Lee."
David McComb, 1987.

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timtam
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Re: Jazzmaster String Breakage Theory

Post by timtam » Sun Feb 16, 2020 4:57 pm

The offset trem is somewhat unique in subjecting the string to bending forces at that location. If you look at other trem designs, they mostly bend the string elsewhere. The usual first suggested fix is soldering that section of string to strengthen it. If they existed, roller ball ends would probably also help; it's arguable whether oiling the ball ends to encourage the string to slide on the ball end could help.

Roller saddles may be helpful on a fixed bridge, as they discourage the string-saddle friction that could allow differential tension developing across the different string sections (ie trem to bridge, bridge to nut). But that would likely be heard as tuning problems - eg if the main string section returned flat after trem action because high saddle friction caused it to stick a little on the saddle, the string section from bridge to saddle would then be under higher tension (ie sharp). Normal rocking bridge function on the other hand requires high saddle friction, and normal rocking encourages maintenance of equalized string section tensions.

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Re: Jazzmaster String Breakage Theory

Post by Horsefeather » Sun Feb 16, 2020 5:32 pm

Note that I wasn't talking about the stock rocking bridge creating a differential in tension between each length of string but torsion. That is, the string twists when the vibrato is used and isn't able to untwist itself like it might with a roller bridge. And yeah--I'm talking about a fixed bridge with roller saddles.

But maybe you're right that it isn't twisting action in the string but bending action down near the ball. I wonder if it would pay to ensure that the ball end is oriented so that the two bits of the loop are in line vertically.

I've also envisioned using a small metal rod through all the ball ends that would serve as an axle and allow them to rotate with the vibrato action. It would need tiny standoffs, though, and mid-span support to remain straight and hold the ball ends away from the holes in the plate.

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Re: Jazzmaster String Breakage Theory

Post by jvin248 » Sun Feb 16, 2020 8:20 pm

.

Helps having a picture of your broken wire.

Assuming you have taken care of the screw head problem already;

Get a small rat-tailed file (Harbor Freight has sets for $3) and file the edges of the through holes where the strings go through the back flange.
You want those nice and smooth. They are probably sharp from the stamping press plus hardened by the chrome.

The string holes where the "8mm" dimension shows in this diagram. I used what I could find on a quick google image search.

Image


.

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Re: Jazzmaster String Breakage Theory

Post by adamrobertt » Sun Feb 16, 2020 10:21 pm

I've never had string breakage issues with an offset vibrato. Guess I'm lucky?

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Re: Jazzmaster String Breakage Theory

Post by Severed Hand » Sun Feb 16, 2020 10:54 pm

Just solder the twist before the ball end on the string

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Re: Jazzmaster String Breakage Theory

Post by Horsefeather » Sun Feb 16, 2020 11:53 pm

Soldering the string isn't an option I'm looking at. I would like to find a remedy for the root cause rather than slap a band-aid on it.

I find it ludicrous that this bridge/vibrato system has been around for over half a century and still suffers from these various debilitating deficiencies. It says a lot about Fender's lack of passion and drive. Leo would not have let this continue.

The Duesenberg Les Trem II is becoming very tempting...

I'm going to try fixing the bridge in place and installing roller saddles like on my Mustang and see if breakage is arrested.

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Re: Jazzmaster String Breakage Theory

Post by JVG » Mon Feb 17, 2020 2:09 am

Horsefeather wrote:
Sun Feb 16, 2020 5:32 pm
But maybe you're right that it isn't twisting action in the string but bending action down near the ball. I wonder if it would pay to ensure that the ball end is oriented so that the two bits of the loop are in line vertically.
I’ve also wondered if the orientation of the ball end has an effect. Difficult theory to test, though.

Also, without wanting to descend into a string brand war, have you had this problem with multiple brands? I stopped using D'Addario on offsets due to breaking or unravelling near the ball, and have had much less trouble with other brands. (BTW i’m still happy with D'Addario on my non-offsets).

Cheers!
J.

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Re: Jazzmaster String Breakage Theory

Post by loveinathens » Mon Feb 17, 2020 2:11 am

JVG wrote:
Mon Feb 17, 2020 2:09 am
Horsefeather wrote:
Sun Feb 16, 2020 5:32 pm
But maybe you're right that it isn't twisting action in the string but bending action down near the ball. I wonder if it would pay to ensure that the ball end is oriented so that the two bits of the loop are in line vertically.
I’ve also wondered if the orientation of the ball end has an effect. Difficult theory to test, though.

Also, without wanting to descend into a string brand war, have you had this problem with multiple brands? I stopped using D'Addario on offsets due to breaking or unravelling near the ball, and have had much less trouble with other brands. (BTW i’m still happy with D'Addario on my non-offsets).

Cheers!
J.
Which brands do you use on your offsets now?

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Re: Jazzmaster String Breakage Theory

Post by JVG » Mon Feb 17, 2020 2:16 am

I haven’t got a ‘favourite’ brand, but lately i’ve been using GHS and Curt Mangan, and have had no string breakage problems.

Cheers,
J.

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Re: Jazzmaster String Breakage Theory

Post by andy_tchp » Mon Feb 17, 2020 2:36 am

andy_tchp wrote:
Sun Feb 16, 2020 4:23 pm
Shit strings. Use something else.
*Cough*
adamrobertt wrote:
Sun Feb 16, 2020 10:21 pm
I've never had string breakage issues with an offset vibrato. Guess I'm lucky?
This. Seriously. Plenty of us don't have this issue. I've used GHS Nickel rockers (and occasionally 'Boomers') with success, probably for over a decade now?

Other people here on OSG have reported excellent results (in the many, many numerous threads on this subject) with D'Addario's 'NYXL' strings that have reinforcement of the ball end. Ditto with Fender 'Bullets' which omit the ball end entirely.
"I don't know why we asked him to join the band 'cause the rest of us don't like country music all that much; we just like Graham Lee."
David McComb, 1987.

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Re: Jazzmaster String Breakage Theory

Post by jvin248 » Mon Feb 17, 2020 5:01 am

.

See if you can post a picture of the string holes on the bridge side and ball end side of that back flange of your trem while holding the position of the broken string to see where that lines up.

Are you finding any burrs or sharp edges at those string holes?

Always the single string or multiple strings?

.

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Re: Jazzmaster String Breakage Theory

Post by Horsefeather » Mon Feb 17, 2020 1:48 pm

I don't pay much attention to what strings I use. I think this set is D'Addario. They're 12 flats. It's only the high E that breaks and when it did the first time it was replaced with whatever brand it was that Guitar Center stocks their singles drawer with and I recall it wasn't D'Addario.

But the issue isn't "shit strings," it's the design of the vibrato.

I've already established that the break in the string pictured is forward of where it might have been rubbing on the hole in the plate. I am confident it's due solely to forces within the string but where those are coming from is the mystery. From this photo of the string before it broke, it appears that break occurred on the bottom of the two string bits. (athough I'm not sure if this is the current string or the previous one that broke so this isn't conclusive at all)

Image

I'm working on overhauling my setup, though. I'm going to swap in the second set of Kahler roller saddles I have. They're narrow, at just 2" E-E spacing, so I think I'm also going to sub in an import vibrato string plate to replace the American one I'm running now, as the import has narrower spacing.

After thinking more about the orientation of the ball ends, I'm now of the mind that arranging the two bits of string coming off the end and through the hole so that they're in line not vertically but horizontally is the way to go. I think it's the vertical arrangement that would cause greater stress.

Anyway, I'm redoing things.

I was just at the hardware store for screws and saw some aluminum channel extrusions that got me thinking about making an entire replacement bridge piece that would have simple bolt holes at either end rather that the threaded posts, which would allow me to bolt it directly to the guitar body after filling the existing holes there. I'd like to have the strings as close to the body as possible because it's much more comfortable to me. These Kahlers end up taller than the stock saddles so any reduction in height elsewhere is welcome.

This post is morphing into a bridge mod project but I still think it might be related to the string breakage problem.

Image
Last edited by Horsefeather on Mon Feb 17, 2020 1:58 pm, edited 1 time in total.

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Pepe Silvia
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Re: Jazzmaster String Breakage Theory

Post by Pepe Silvia » Mon Feb 17, 2020 1:58 pm

I run Ernie Ball RPS Slinkies to fix this issue. I have never had a breakage like this since.

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