Stewmac shims

For help with setups and other technical issues.
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schoolie
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Re: Stewmac shims

Post by schoolie » Fri Nov 20, 2020 4:51 pm

Put a 1.0 and 0.25 in my AVRI Jag. I like the sound with the higher break angle...and the strings clear the trem screws.

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Norrin Radd
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Re: Stewmac shims

Post by Norrin Radd » Tue Nov 24, 2020 7:42 pm

I’m putting together my 1st JM partscaster. Is a shim recommended for optimal setup? And if so, what is the rationale? Sorry for the n00b questions. :whistle:

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Larry Mal
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Re: Stewmac shims

Post by Larry Mal » Tue Nov 24, 2020 8:25 pm

Norrin Radd wrote:
Tue Nov 24, 2020 7:42 pm
I’m putting together my 1st JM partscaster. Is a shim recommended for optimal setup? And if so, what is the rationale? Sorry for the n00b questions. :whistle:
Not at all.

So, Jazzmasters were kind of designed around the concept of heavy strings, jazz players tend to use those and when the Jazzmaster was released there weren't any lighter sets as we understand them today.

The bridge tends to want more pressure on it than what today's light string gauges provide. Adding a shim gets you there.

Now, you might use a different bridge like a Mustang or a Mastery, which don't need as much pressure to keep the saddles in place like a traditional Jazzmaster bridge.

However, some Fenders are made with shallower neck pockets, and so you might not be able to get the action low as you might like it. You'll know because the bridge hits the top of the guitar, and you still wish you had lower action. This is when you need a shim, also.

Me, I took a cue from Gibson and other set neck guitar makers, who absolutely have to put an angle on those necks otherwise the entire guitar might not work and you can't really fix it. So over the years I came to conclude that a neck angle is best on all guitars, so I just put shims on my Fenders anyway.
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Norrin Radd
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Re: Stewmac shims

Post by Norrin Radd » Wed Nov 25, 2020 7:27 am

Larry Mal wrote:
Tue Nov 24, 2020 8:25 pm
Norrin Radd wrote:
Tue Nov 24, 2020 7:42 pm
I’m putting together my 1st JM partscaster. Is a shim recommended for optimal setup? And if so, what is the rationale? Sorry for the n00b questions. :whistle:
Not at all.

So, Jazzmasters were kind of designed around the concept of heavy strings, jazz players tend to use those and when the Jazzmaster was released there weren't any lighter sets as we understand them today.

The bridge tends to want more pressure on it than what today's light string gauges provide. Adding a shim gets you there.

Now, you might use a different bridge like a Mustang or a Mastery, which don't need as much pressure to keep the saddles in place like a traditional Jazzmaster bridge.

However, some Fenders are made with shallower neck pockets, and so you might not be able to get the action low as you might like it. You'll know because the bridge hits the top of the guitar, and you still wish you had lower action. This is when you need a shim, also.

Me, I took a cue from Gibson and other set neck guitar makers, who absolutely have to put an angle on those necks otherwise the entire guitar might not work and you can't really fix it. So over the years I came to conclude that a neck angle is best on all guitars, so I just put shims on my Fenders anyway.
Hey - thanks for the info! That makes a lot of sense. As a guy who has pretty much played mostly Stratocaster‘s and telecasters, do you think it makes sense to maintain the same gauge strings as I am used to, or would you recommend an increased gauge size due to the nature of the jazzmaster? I currently use 9 - 46s on my Strats & Teles. I’m thinking a 10- 52 set for the jazzmaster might be the way to go? Plus a shim? FWIW, I’m used to having to install shims. One of my Strats, the one that actually plays the best, has a StewMac .25 in it.

Thanks for any advice! I’m actually really excited to get this thing together once all the parts arrive! :w00t:

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Larry Mal
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Re: Stewmac shims

Post by Larry Mal » Wed Nov 25, 2020 8:03 am

Norrin Radd wrote:
Wed Nov 25, 2020 7:27 am


Hey - thanks for the info! That makes a lot of sense. As a guy who has pretty much played mostly Stratocaster‘s and telecasters, do you think it makes sense to maintain the same gauge strings as I am used to, or would you recommend an increased gauge size due to the nature of the jazzmaster? I currently use 9 - 46s on my Strats & Teles. I’m thinking a 10- 52 set for the jazzmaster might be the way to go? Plus a shim? FWIW, I’m used to having to install shims. One of my Strats, the one that actually plays the best, has a StewMac .25 in it.

Thanks for any advice! I’m actually really excited to get this thing together once all the parts arrive! :w00t:
No, you might read in places that you have to use different gauges with Jazzmasters but that's bad and outdated advice.

With a proper setup, and a proper understanding of how to set up your offset, you can use any string gauge you might feel comfortable with. I always have personally.

When I say "proper setup", though, that might involve a shim in order to increase the pressure on the saddles, or you might consider a Mustang type bridge which is much easier to set up than the stock Jazzmaster kind with all the individual hyper-adjustable saddles, which I've never liked. There's a lot of bridge choices out there now and the only one that needs all this extra precautions with tends to be the original, vintage kind, and that's the only kind there was for decades, so a lot of what you read on the internet fails to take into account all the new equipment that simply wasn't around for most of the Jazzmaster's history.

But you should take the mindset of being able to use whatever strings you prefer and then make your guitar accommodate that, rather than have to adjust yourself around your guitar. No need to do that.

Let us know how you get on!
Back in those days, everyone knew that if you were talking about Destiny's Child, you were talking about Beyonce, LaTavia, LeToya, and Larry.

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Re: Stewmac shims

Post by HarlowTheFish » Wed Nov 25, 2020 12:29 pm

Norrin Radd wrote:
Wed Nov 25, 2020 7:27 am
Hey - thanks for the info! That makes a lot of sense. As a guy who has pretty much played mostly Stratocaster‘s and telecasters, do you think it makes sense to maintain the same gauge strings as I am used to, or would you recommend an increased gauge size due to the nature of the jazzmaster? I currently use 9 - 46s on my Strats & Teles. I’m thinking a 10- 52 set for the jazzmaster might be the way to go? Plus a shim? FWIW, I’m used to having to install shims. One of my Strats, the one that actually plays the best, has a StewMac .25 in it.

Thanks for any advice! I’m actually really excited to get this thing together once all the parts arrive! :w00t:
To get a nicely dialed-in setup that works as designed, a shim is basically required unless you get a body with a pre-angled neck pocket or get extremely lucky with pocket/neck depth and it just sits in a good place. So basically just get one, odds are you'll need it - a set of the 0.5deg ones is pretty good (you can stack them if you need to), or one set of 0.5 and one of 0.25deg will give you the most flexibility.

As far as using heavier strings, you don't need to per se if you have a good setup, but you might want some because the compliance of the strings is different on the offsets, and while the tension is the same (as measured in lbs/kg) as a Strat or Tele, because there's more total string length to stretch, the whole thing feels a bit softer to play. So not needed necessarily, but you might want them anyway - try your usual set and see how you like it, you might want it to feel a bit different or more similar to how your Strats and Teles do.

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Norrin Radd
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Re: Stewmac shims

Post by Norrin Radd » Wed Nov 25, 2020 5:17 pm

Larry Mal wrote:
Wed Nov 25, 2020 8:03 am
But you should take the mindset of being able to use whatever strings you prefer and then make your guitar accommodate that, rather than have to adjust yourself around your guitar. No need to do that.

Let us know how you get on!
Will do! I suppose I should start my own thread over in the projects forum. I'll report there as the pieces come in and she gets herself together!

Too everyone - thanks for all your help & advice!

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timtam
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Re: Stewmac shims

Post by timtam » Wed Nov 25, 2020 5:24 pm

Norrin Radd wrote:
Tue Nov 24, 2020 7:42 pm
I’m putting together my 1st JM partscaster. Is a shim recommended for optimal setup? And if so, what is the rationale? Sorry for the n00b questions. :whistle:
First question ... you're planning on using the rocking bridge, right ? The setup requirements for a fixed bridge like Fender's AOMs or Mastery are somewhat different.

Assuming rocking bridge, what you are trying to achieve is sufficient string-saddle downforce. That can be achieved in several ways. In an ideal world we would have a calculator for what combination of things get you to where you need to be downforce-wise. No single factor like heavier gauge strings are absolutely necessary - you can get by with regular gauges if you do other things right. It also depends to some extent on how hard you play (whether strings stay in their grooves .. Mustang-style bridges have deeper grooves if you play heavy, but don't usually have radius adjustment), and how much you plan on using the trem.

Sufficient string-saddle downforce gives you the string-saddle friction necessary for consistent trem function, and also to minimise potential sources of bridge rattle. That often requires an angled neck pocket (built into some modern models, or via a tapered shim), to get the bridge high enough for good string break angle - along with sufficient string gauge (string tension) that break angle is what gets you good downforce on the rocking bridge.

It sounds a bit complicated but it's really no more complex than say setting up a floating strat trem, or the myriad inconclusive discussions about Les Paul top-wrapping/break angles/stop bar height. The principles are actually more straightforward than for those.

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