Johnny Marr Jag Shims and Setup

[RoséBear]

So I ran into some Johnny Marr jag parts. Need some help putting them together. I have the bridge and tremolo.

The body and neck are Fender Japan, currently with no shim. Would you guys recommend a shim for the Johnny Marr bridge?

Also, the bridge rocks, as per the original design. I had the idea to fit the thimbles with the nylon bushings, included in the American professional guitars, so that the bridge will still rock fairly freely with trem use, but always return back to the zero point. You guys think that’s a good idea?

[jorri]

Shims are about one thing: the bridge height.
They are used supposedly due to tolerances in design.
So it depends how high the bridge is.
Since johnny marr bridge fixes most issues it probably wont unless it ends up nearly touching the body.

And the bridge is meant to rock. It even helps tuning rocking. But its not meant to end up stuck tilted leaning toward the neck, which would be more a reason for stopping it. Up to you, might feel a bit more like a tune o matic.

[Danley]

I’ve never *needed* the nylon bushings; the bridge should stay pretty well put after you initially center it. It should take firm/direct effort to deliberately un-center it. But you can try it without the bushings first, and add them later if you have any problems.

If your action is fine without a shim, you don’t need a shim.

[RoséBear]

Shims are about one thing: the bridge height.
They are used supposedly due to tolerances in design.
So it depends how high the bridge is.
Since johnny marr bridge fixes most issues it probably wont unless it ends up nearly touching the body.

And the bridge is meant to rock. It even helps tuning rocking. But its not meant to end up stuck tilted leaning toward the neck, which would be more a reason for stopping it. Up to you, might feel a bit more like a tune o matic.

Thanks! I thought that shims also effect the tension of the strings on the bridge and break angle?

[timtam]

In an ideal world we would know the string-saddle friction force necessary for reliable continuous gripping of the saddles by the strings during trem use (that ensures that a rocking bridge actually rocks fully and thus returns to where it started). Then we could prescribe a suitable combination of settings for the things that determine that friction (saddle material, groove profile, string break angles, string gauge, string coating).

Obviously we don't really have the capability to determine/measure those easily; except string gauge, and bridge height (a proxy for break angles). So we work with rules of thumb. If you use the trem a lot and the bridge is not returning to where it started (or moving away from neutral with little or no trem use), then your string-saddle friction is probably too low. You can increase that most readily by a higher string gauge and/or increasing string break angle. For both, small changes can have a large effect on friction. Re break angle, if your action is already where you want it, then the options to increase string break angles are a tapered shim or the buzz stop. A tapered shim has the advantage of affecting both front and back string break angles more similarly than the buzz stop, which only affects the back break angle (and will result in somewhat unbalanced fore/aft string forces on the rocking bridge) [the buzz stop also affects the way the 'residual' string region behind the bridge operates]. A shim has the disadvantage of being limited by bridge height - if your bridge is already near its upper limit, then you may not have room for the shim to require it to go higher (to get the same pre-shim action).

In a nut shell, if you think you need a shim (either because you have a problem, or anticipate one) .... try it.

[ChrisDesign]

Shims are about one thing: the bridge height.
They are used supposedly due to tolerances in design.
So it depends how high the bridge is.
Since johnny marr bridge fixes most issues it probably wont unless it ends up nearly touching the body.

And the bridge is meant to rock. It even helps tuning rocking. But its not meant to end up stuck tilted leaning toward the neck, which would be more a reason for stopping it. Up to you, might feel a bit more like a tune o matic.

Shimming a neck is fine if needed. The Fender custom shop shim many neck pockets.

My Jazzmaster Standard's bridge used to buzz a little. I added a Stew Mac .5 degree shim under the neck and this fixed the problem. The problem was the break angle at the bridge was too shallow for my desired action. After I shimmed the neck, the guitar 'feels' more solid, the tone is less 'jangly', and the buzzing is eliminated. I wish I had, in hindsight, used a .25 degree shim instead of a .5 shim.

You should build the guitar and see how the bridge works. Shim with a .25 if your bridge buzzes a little. If it still buzzes, fit a .5 shim.

[Webrocker]

The Marr Jag's neck pocket is routed so that the neck already has a slight (~1°?] angle, so my guess is if you have a standard neck pocket on your body, a shim would help to get the set up where it is at on a Marr Jag.
I had problems getting the best out of a Mastery bridge on a Marr Jag for that reason - due to the pocket routing, I couldn't lower the mastery beyond a certain point, which was way higher than the same Mastery on a non shimmed Jag.

[jorri]

Shims are about one thing: the bridge height.
They are used supposedly due to tolerances in design.
So it depends how high the bridge is.
Since johnny marr bridge fixes most issues it probably wont unless it ends up nearly touching the body.

And the bridge is meant to rock. It even helps tuning rocking. But its not meant to end up stuck tilted leaning toward the neck, which would be more a reason for stopping it. Up to you, might feel a bit more like a tune o matic.

Shimming a neck is fine if needed. The Fender custom shop shim many neck pockets.

My Jazzmaster Standard's bridge used to buzz a little. I added a Stew Mac .5 degree shim under the neck and this fixed the problem. The problem was the break angle at the bridge was too shallow for my desired action. After I shimmed the neck, the guitar 'feels' more solid, the tone is less 'jangly', and the buzzing is eliminated. I wish I had, in hindsight, used a .25 degree shim instead of a .5 shim.

You should build the guitar and see how the bridge works. Shim with a .25 if your bridge buzzes a little. If it still buzzes, fit a .5 shim.

Yes bridge height proportional to break angle.
I do use a shim, but its a Warmoth and they can be quite low.
No problem with one, in fact card does a good job as it compresses (or the mentioned stewmac full pocket, sure, it probably prevents potential warps at heel) but also there is a sort of non-linear trade of with buzz in relation to angle.
Like maybe if its 1° then 2° (break angle) reduces it.or if its 4° then 8° would help as much as the former change- but 8 would be ridiculous and set up with the bridge sticking out like a cello and a bunch of alternate problems. So not much further you can go if its high enough... Certainly would never be a strat bridge angle.