the_devils_tool
Joined: Jul 09, 2018
Posts: 24
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Posted on Jul 12 2020 12:39 PM
I did a search before asking this and didn't find exactly the answer I was looking for so here goes -
I've got some AllParts JM/Jag Vibrato units, the springs are of varying tension. The one guitar that I have that is the smoothest/softest spring actually looks like the spring was chopped almost in half. Instead of buying a specific version spring (Reverend pops up on Gretsch forums too for softer Bigsby action) - has anyone here instead chopped their spring and gotten a softer trem action with less tension?
Car guys used to cut springs on rides before everybody in the world started producing custom springs, so it's entirely possible, just don't know if it's worth hacking up one of my spare springs to try it out.
Thoughts?
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Squid
Joined: Aug 22, 2010
Posts: 1011
Portland, Oregon with Insanitizers
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Posted on Jul 13 2020 11:13 AM
From the viewpoint of physics, the resistance of a spring to a specific force should decrease with the amount of metal involved in the resistance, i.e., the number of spring coils. So your idea should work. I have not tried it.
An obvious problem is that the end of the cut spring must be modified so it will not slip off the holder. It may work better to cut a section from the middle of the spring than remove an end. Then you need to join the two broken parts in the middle. I don't know the best way to do this, but I expect it will wind up being time consuming and add costs, so buying a softer spring seems more economical and practical.
— Insanitizers! http://www.insanitizers.com
Last edited: Jul 13, 2020 11:14:11
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Sonichris
Joined: Mar 06, 2006
Posts: 1872
Wear gloves - I'm in the Rockies
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Posted on Jul 13 2020 01:54 PM
Springs like these have a linear rate - that is, if it takes 10 pounds to move it a half inch, it will take another 10 pounds to move it another half inch. Keep adding weight, and eventually the spring will compress completely. Cutting it doesn't change the spring rate, it just makes the spring shorter.
When people talk about "tightening the spring" really, they are just moving the the whole, already preloaded spring up. They aren't increasing the spring rate - it's what it is.
So, a set of 10-46 strings might compress the spring 1/4", and a set of 12-52's might compress it 1/2". the tremolo adjustment screw just pulls that preloaded spring and collet (and plate with the tremolo arm) closer or further from the top plate depending on the screw position.
You also have to take spring travel into consideration - cutting it will reduce the amount that spring can be compressed, but not the rate.
So, in a case like this, you'd need a softer spring rate, at the same length or maybe slightly longer, depending on the rate. but not shorter.
Does that make sense?
— "You can't tell where you're going if you don't know where you've been"
Last edited: Jul 13, 2020 16:20:36
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raylinds
Joined: Jul 05, 2019
Posts: 141
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Posted on Jul 13 2020 10:14 PM
Sonichris wrote:
Springs like these have a linear rate - that is, if it takes 10 pounds to move it a half inch, it will take another 10 pounds to move it another half inch. Keep adding weight, and eventually the spring will compress completely. Cutting it doesn't change the spring rate, it just makes the spring shorter.
When people talk about "tightening the spring" really, they are just moving the the whole, already preloaded spring up. They aren't increasing the spring rate - it's what it is.
So, a set of 10-46 strings might compress the spring 1/4", and a set of 12-52's might compress it 1/2". the tremolo adjustment screw just pulls that preloaded spring and collet (and plate with the tremolo arm) closer or further from the top plate depending on the screw position.
You also have to take spring travel into consideration - cutting it will reduce the amount that spring can be compressed, but not the rate.
So, in a case like this, you'd need a softer spring rate, at the same length or maybe slightly longer, depending on the rate. but not shorter.
Does that make sense?
Perfect sense. Cutting the spring will not reduce tension.
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the_devils_tool
Joined: Jul 09, 2018
Posts: 24
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Posted on Jul 14 2020 07:34 AM
Appreciate the info - makes sense!
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symbiotic
Joined: Aug 27, 2018
Posts: 12
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Posted on Jul 14 2020 11:51 AM
One more way to phrase it, though I may be too late to help:
The strings exert a given force on the vibrato which is dependent on string guage and the pitch you are tuned to. For the vibrato to be in a balanced, floating position, its spring must be exactly balancing this out. You can change the resting position of the arm by preloading the spring or changing the spring length but once it is set up in a floating, balanced position, it is still exerting the same force to balance the string tension.
If you use a longer arm you will achieve a softer feel through its greater leverage, and it will reduce the amount of pitch change for a given movement at the arm's tip.
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Ben
Joined: Feb 11, 2007
Posts: 591
Encinitas, Ca
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Posted on Jul 15 2020 03:17 PM
Try checking Ace Hardware. They usually have a few drawers of different types and stiffness of springs. You might get lucky and find something just right.
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the_devils_tool
Joined: Jul 09, 2018
Posts: 24
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Posted on Jul 15 2020 05:21 PM
Will do! I'm getting a lot of physics info (which makes sense, even though I'm not a science guy) and most of it is telling me that cutting it won't do much at all.
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synchro
Joined: Feb 02, 2008
Posts: 4108
Not One-Sawn, but Two-Sawn . . . AZ.
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Posted on Jul 15 2020 11:24 PM
the_devils_tool wrote:
Will do! I'm getting a lot of physics info (which makes sense, even though I'm not a science guy) and most of it is telling me that cutting it won't do much at all.
If anything, cutting will make it stiffer. A coil spring is a torsion bar. If you have a torsion bar that you can twist 90 degrees by hand, and cut it to half length, you will only be able to twist it 45 degrees.
— The artist formerly known as: Synchro
When Surf Guitar is outlawed only outlaws will play Surf Guitar.
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ldk
Joined: Nov 08, 2017
Posts: 356
San Francisco Bay Area
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Posted on Jul 20 2020 12:13 AM
I'm not a physicist, but I play one on TV.
By Hooke's Law, the force to compress a spring a distance of x is k times x, where k is a constant dependent on the spring. Two identical springs connected in series have a spring constant of k/2, and a spring cut in half has a spring constant of 2k.
So, if F is the force to compress a spring a distance x, 2F is required to compress half the spring a distance of x.
So, it seems that half the spring is stiffer.
— If I'd stop buying old guitars to fix, I might actually learn to play.
Bringing instruments back to life since 2013.
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Squid
Joined: Aug 22, 2010
Posts: 1011
Portland, Oregon with Insanitizers
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Posted on Jul 21 2020 02:19 PM
ldk I can see you are correct through this example:
Two identical springs in series will stretch twice as much as one spring in response to a given weight. So, half a spring will stretch half as much as a whole spring in response to that weight. It will take twice the weight to stretch the half spring as much as a whole spring stretches.
— Insanitizers! http://www.insanitizers.com
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ldk
Joined: Nov 08, 2017
Posts: 356
San Francisco Bay Area
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Posted on Jul 21 2020 05:39 PM
Squid wrote:
Two identical springs in series will stretch twice as much as one spring in response to a given weight. So, half a spring will stretch half as much as a whole spring in response to that weight. It will take twice the weight to stretch the half spring as much as a whole spring stretches.
Good examples. Very clear.
— If I'd stop buying old guitars to fix, I might actually learn to play.
Bringing instruments back to life since 2013.
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