AVRI Trem Lock Button Setup

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baseggio
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AVRI Trem Lock Button Setup

Post by baseggio » Sat Nov 03, 2018 12:53 pm

I've been in the process of upgrading my Squire J Mascis Jazzmaster for a while and I finally got an AVRI Trem installed in it. It feels quite a bit heavier and the way it holds the (new) arm in is much nicer. So far so good.

I set about to set it up and configure it according to this article https://offset.guitars/the-goodies/sett ... lo-system/. Basically, if I understand correctly, the idea is to loosen the adjustment screw just enough that you can slide the lock button in with the tremolo barely engaged. Doing this means that when you engage the lock, you only get to operate the tremolo one way, but you'll be in tune. Sounds handy if you break a string or just happen to get out of tune in the middle of a song.

So I set about to do this and even at its loosest setting, I still have to really jam on the tremolo to get the lock button to engage. To the point where the adjustment screw is actually starting to come up out of the tremolo assembly.

Now, the article I linked does contain this key note:
Note: Some vintage systems seem to have very strong springs, so that the “balanced” position will not be possible even with the tension loosened as far as possible. This happens usually with string sets lighter than .11s (.10s on the JM).
I'm using 10's. Am I just hosed on getting the lock button to work?

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Danley
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Re: AVRI Trem Lock Button Setup

Post by Danley » Sat Nov 03, 2018 1:01 pm

I use 9s on my Jaguar (AVRI vibrato) and the lock button works.

I use 9s on my Jazzmaster (MIJ) and the lock button will not work- string tension is not sufficient.
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Re: AVRI Trem Lock Button Setup

Post by solfege » Sat Nov 03, 2018 2:14 pm

I use 10s on my JM and my Jag. Both have AVRIs now. Works on both of them. Maybe shim the neck a little?

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Re: AVRI Trem Lock Button Setup

Post by baseggio » Sat Nov 03, 2018 2:21 pm

solfege wrote:
Sat Nov 03, 2018 2:14 pm
I use 10s on my JM and my Jag. Both have AVRIs now. Works on both of them. Maybe shim the neck a little?
Ooh, hadn't thought of that! I know that helps with break angle and keeping E strings in place, but why would that help with the trem? Just more tension on the strings?

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Re: AVRI Trem Lock Button Setup

Post by timtam » Sat Nov 03, 2018 4:20 pm

baseggio wrote:
Sat Nov 03, 2018 2:21 pm
solfege wrote:
Sat Nov 03, 2018 2:14 pm
I use 10s on my JM and my Jag. Both have AVRIs now. Works on both of them. Maybe shim the neck a little?
Ooh, hadn't thought of that! I know that helps with break angle and keeping E strings in place, but why would that help with the trem? Just more tension on the strings?
That may well help. Logical sequence something like this ? ...

Shimmed neck
Increased neck angle
Higher bridge
Greater string break angle over bridge (and downforce on bridge)
Greater string angle at trem
Greater mechanical advantage of strings over trem
More of the existing string force going towards rotating trem downwards (greater string torque on trem)
Front of trem plate sits lower in trem cavity
Lock easier to engage

Heavier strings work in the same way (greater string force on trem).

You still have to move the trem down by the same physical distance to engage the lock. It should just be easier. But if your spring screw is still near its endpoint before the lock engages that could still be an issue ?
"I just knew I wanted to make a sound that was the complete opposite of a Les Paul, and that’s pretty much a Jaguar." Rowland S. Howard.

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Re: AVRI Trem Lock Button Setup

Post by solfege » Sat Nov 03, 2018 7:22 pm

What timtam said.

It occurred to me b/c my jag body has a pretty serious neck angle in the pocket and my MIJ JM that I just put another AVRI trem on had it's neck shimmed when a friend redid the nut and set it up -- and I always set my trems up in the very traditional way: lock button would keep the strings in tune if one broke.

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Re: AVRI Trem Lock Button Setup

Post by Danley » Sat Nov 03, 2018 9:00 pm

Quicker by far to string the guitar with it engaged; less re-tuning.
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Re: AVRI Trem Lock Button Setup

Post by baseggio » Sun Nov 04, 2018 4:59 am

Danley wrote:
Sat Nov 03, 2018 9:00 pm
Quicker by far to string the guitar with it engaged; less re-tuning.
I thought of that too. You only get one direction of tremolo, but I'm not a huge tremelo user and going lower is mostly what I'd want.

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Re: AVRI Trem Lock Button Setup

Post by baseggio » Sun Nov 04, 2018 9:38 am

I'm also wondering if putting the spring from the JM JM trem unit would help, since it's not as tight. Or would that just be sacrificing something good from the AVRI trem?

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Re: AVRI Trem Lock Button Setup

Post by Gevalt » Mon Nov 05, 2018 9:07 am

baseggio wrote:
Sat Nov 03, 2018 12:53 pm
I finally got an AVRI Trem installed in it. It feels quite a bit heavier
How can the AVRI trem be heavier? It's half the thickness, and unless my upgrade experience was wrong, that Squier sumbich is heavy.
baseggio wrote:
Sun Nov 04, 2018 9:38 am
I'm also wondering if putting the spring from the JM JM trem unit would help, since it's not as tight. Or would that just be sacrificing something good from the AVRI trem?
I switched out the spring in my VI 3 years ago and noticed nothing, so put it away. I'll sell you my tested AVRI spring for $5.00USD plus stamps.

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Re: AVRI Trem Lock Button Setup

Post by kgbAttack » Tue Nov 20, 2018 1:40 pm

timtam wrote:
Sat Nov 03, 2018 4:20 pm
baseggio wrote:
Sat Nov 03, 2018 2:21 pm
solfege wrote:
Sat Nov 03, 2018 2:14 pm
I use 10s on my JM and my Jag. Both have AVRIs now. Works on both of them. Maybe shim the neck a little?
Ooh, hadn't thought of that! I know that helps with break angle and keeping E strings in place, but why would that help with the trem? Just more tension on the strings?
That may well help. Logical sequence something like this ? ...

Shimmed neck
Increased neck angle
Higher bridge
Greater string break angle over bridge (and downforce on bridge)
Greater string angle at trem
Greater mechanical advantage of strings over trem
More of the existing string force going towards rotating trem downwards (greater string torque on trem)
Front of trem plate sits lower in trem cavity
Lock easier to engage

Heavier strings work in the same way (greater string force on trem).

You still have to move the trem down by the same physical distance to engage the lock. It should just be easier. But if your spring screw is still near its endpoint before the lock engages that could still be an issue ?
I have just replaced the Squier Vibrato with a spare AVRI Vibrato, and following the guideline I was trying to adjust the trem lock screw but I am not sure I'm doing it ok as I keep tightening the screw but the lock seems to engage with no obstacles yet. Did I go to far? :unsure:

Image

Image

Image

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Re: AVRI Trem Lock Button Setup

Post by timtam » Tue Nov 20, 2018 4:09 pm

kgbAttack wrote:
Tue Nov 20, 2018 1:40 pm
I have just replaced the Squier Vibrato with a spare AVRI Vibrato, and following the guideline I was trying to adjust the trem lock screw but I am not sure I'm doing it ok as I keep tightening the screw but the lock seems to engage with no obstacles yet. Did I go to far? :unsure:
If you haven't used a lockable trem much before, just how far down that lock button is supposed to move can be hard to determine if it's not working right. With the screw loosened all the way the lock should slide in and out easily. Sometimes it's worth taking the trem off and playing with the lock out of the guitar to feel and see (underneath) how it should work.

It's hard to tell from your pics, but if you have tightened the spring screw too far, it's possible that the lock is in this position now, where it can still move a little ....
Image

.. instead of the correct screw position, where the lock can move back and forth much more, and further down into the true locked position ..
Image

https://offset.guitars/the-goodies/sett ... lo-system/
"I just knew I wanted to make a sound that was the complete opposite of a Les Paul, and that’s pretty much a Jaguar." Rowland S. Howard.

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Re: AVRI Trem Lock Button Setup

Post by kgbAttack » Wed Nov 21, 2018 1:48 am

timtam wrote:
Tue Nov 20, 2018 4:09 pm
kgbAttack wrote:
Tue Nov 20, 2018 1:40 pm
I have just replaced the Squier Vibrato with a spare AVRI Vibrato, and following the guideline I was trying to adjust the trem lock screw but I am not sure I'm doing it ok as I keep tightening the screw but the lock seems to engage with no obstacles yet. Did I go to far? :unsure:
If you haven't used a lockable trem much before, just how far down that lock button is supposed to move can be hard to determine if it's not working right. With the screw loosened all the way the lock should slide in and out easily. Sometimes it's worth taking the trem off and playing with the lock out of the guitar to feel and see (underneath) how it should work.

It's hard to tell from your pics, but if you have tightened the spring screw too far, it's possible that the lock is in this position now, where it can still move a little ....
Image

.. instead of the correct screw position, where the lock can move back and forth much more, and further down into the true locked position ..
Image

https://offset.guitars/the-goodies/sett ... lo-system/
Thank you! so I tried again this morning and it appears that the lock engages well (and cannot really use the vibrato upward), however the collet rest position looks more like the first image than the position perpendicular to the vibrato as in the second image.

I drop the E string to C# often so this is gonna be a big help for me!

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Re: AVRI Trem Lock Button Setup

Post by oid » Wed Nov 21, 2018 2:57 am

Increasing the height of the bridge actually decreases mechanical advantage and unbalances the system. We get the greatest mechanical advantage with the force applied at 90 degrees to the lever, the strings are the load, not part of the lever, with the spring being the load on the other side of the teeter totter. The arm of the lever the strings act upon is perpendicular to our guitars top, so for optimum mechanical advantage we would want the strings parallel to the top of the guitar, but that is not practical, we need some down force on the bridge so we accept less than perfect and dick around with the spring tension to get us as close to balanced as we can get. Increasing the height still could help, if the trem is not sitting on the pivot properly, a little upward pull from the strings may help get it seated and keep it there. Giving the part the strings anchor on a push downward or pulling up on it can solve this issue as well, it is not hard to knock the trem out of alignment with the pivot, especially when there is no string tension to balance out the spring.

The above graphic does not show the pivot at all correctly.
Image
If you look at this one you can see the trem rests on the corner of the pivot, not the face and there is an area with a sharp bend in the tremolo that the pivot sits against. If the pivot is moved off this spot we get issues, we have unbalanced the teeter totter. Push the string end of the trem into the body and now the spring has a longer lever and more mechanical advantage pushing the front of the trem up, along with the collet, pull it out and the opposite, the front and collet dives under. Sometimes the point the pivot bears against is less than perfect and it can get knocked out very easily, sometimes the pivot wears and becomes rounded, same result and sometimes either the pivot or the bend is wrong and it never works correctly. The design of the tremolo means we can not actually pull it out to far, the curve beneath the pivot and the load will pop it back, but we can push it in and out of align. It is a complex little system.
Logic gates based on billiard-ball computer designs have also been made to operate using live soldier crabs of the species Mictyris guinotae in place of the billiard balls.

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Re: AVRI Trem Lock Button Setup

Post by timtam » Wed Nov 21, 2018 4:04 am

oid wrote:
Wed Nov 21, 2018 2:57 am
Increasing the height of the bridge actually decreases mechanical advantage and unbalances the system. We get the greatest mechanical advantage with the force applied at 90 degrees to the lever, the strings are the load, not part of the lever, with the spring being the load on the other side of the teeter totter. The arm of the lever the strings act upon is perpendicular to our guitars top, so for optimum mechanical advantage we would want the strings parallel to the top of the guitar, but that is not practical, we need some down force on the bridge so we accept less than perfect and dick around with the spring tension to get us as close to balanced as we can get. Increasing the height still could help, if the trem is not sitting on the pivot properly, a little upward pull from the strings may help get it seated and keep it there. Giving the part the strings anchor on a push downward or pulling up on it can solve this issue as well, it is not hard to knock the trem out of alignment with the pivot, especially when there is no string tension to balance out the spring.

The above graphic does not show the pivot at all correctly.
Image
If you look at this one you can see the trem rests on the corner of the pivot, not the face and there is an area with a sharp bend in the tremolo that the pivot sits against. If the pivot is moved off this spot we get issues, we have unbalanced the teeter totter. Push the string end of the trem into the body and now the spring has a longer lever and more mechanical advantage pushing the front of the trem up, along with the collet, pull it out and the opposite, the front and collet dives under. Sometimes the point the pivot bears against is less than perfect and it can get knocked out very easily, sometimes the pivot wears and becomes rounded, same result and sometimes either the pivot or the bend is wrong and it never works correctly. The design of the tremolo means we can not actually pull it out to far, the curve beneath the pivot and the load will pop it back, but we can push it in and out of align. It is a complex little system.
You've got me thinking more on the mechanical advantage. But based on the usually downward angle of the lever arm (the part that extends above the body) to the pivot, the ideal string angle (for 90deg pull) would be down into the body, not parallel to it, ie even more impractical. Pushing down on the trem will take the lever-to-string angle even further from the ideal 90degs. Pulling up on it gets it closer to the ideal 90deg pull. So pure mechanical advantage in terms of leverage varies through the trems range, as does string tension, thus changing the balance.

The effect of the string tension is twofold: (1) to exert a torque (dependent on angle of pull) on the trem around the pivot (balanced by the spring), and (2) to exert compressive force on the pivot, increasing friction somewhat.

You are right about the pivot edge drawings from that website. The best pics I've seen of how it should be are figure 4a in Leo's original patent (if you look very closely) and this pic of the Mastery trem's pivot .. and now your drawing. ;) The end of the plate is not square, as it is only supposed to ever pivot on the upper edge, which is deliberately favoured in the angled way the plate edge is cut (on the better trems) ...
http://www.offsetguitars.com/forums/vie ... t#p1507248
Image
"I just knew I wanted to make a sound that was the complete opposite of a Les Paul, and that’s pretty much a Jaguar." Rowland S. Howard.

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