I'm still doing the body, but I'm thinking ahead.
Now most guitars seem to have coated steel wire which naturally provides a robust and heavy tailpiece. The same opinions seem to refer to nylon as the material provided with most of the beginner cellos but kevlar being a preferred alternative.
I can see that the weight of the tail will affect the string-bridge relationship with steel being heavier and kevlar being lighter with less stretch. I'm leaning towards kevlar as it's lighter, lower stretch and it's rated well over the 90Kg of the design.
I don't think there's much in it but I figured I'd ask.
It'll be into a dense wood tailpiece.
archtop tail gut material - nylon / steel / kevlar?
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Nick Kitchener
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Alan Carruth
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Re: archtop tail gut material - nylon / steel / kevlar?
The weight of the tailpiece certainly matters, but I doubt the weight of the tailgut has much of a primary effect.
In the simplest model, with a hinge at the lower end, the tailpiece is a mass that pivots at one end and is held up by a spring (the back strings) at the other. It 'flaps' up and down at a pitch that is determined by the strength of the spring, the mass, and the location of the center of moment of the system. It exerts a vertical force on the bridge at that pitch. The shorter the back strings and the closer to the bridge the center of moment is the more force is coupled to the bridge. I more complex models with a tailgut the tailpiece can also twist from side to side. You have to take into account the spread of the two ends of the tailgut on it's saddle.
On my first archtop Classical guitar I used a very light tailpiece. The resonant pitch was high, as expected. As an experiment I added mass to it as close as possible to the bridge. When the tailpiece resonance approached the 'main air' pitch of the guitar it could couple strongly with the vertical motion of the top. I took the instrument to a friend's shop to show it to him, but he was not in. His partner, who is a good Classical player, was playing it when my friend walked in. He asked about the added weight on the tailpiece, so I reached over and removed it. "Who turned off the speaker!?", he exclaimed. It can make a difference.
In the simplest model, with a hinge at the lower end, the tailpiece is a mass that pivots at one end and is held up by a spring (the back strings) at the other. It 'flaps' up and down at a pitch that is determined by the strength of the spring, the mass, and the location of the center of moment of the system. It exerts a vertical force on the bridge at that pitch. The shorter the back strings and the closer to the bridge the center of moment is the more force is coupled to the bridge. I more complex models with a tailgut the tailpiece can also twist from side to side. You have to take into account the spread of the two ends of the tailgut on it's saddle.
On my first archtop Classical guitar I used a very light tailpiece. The resonant pitch was high, as expected. As an experiment I added mass to it as close as possible to the bridge. When the tailpiece resonance approached the 'main air' pitch of the guitar it could couple strongly with the vertical motion of the top. I took the instrument to a friend's shop to show it to him, but he was not in. His partner, who is a good Classical player, was playing it when my friend walked in. He asked about the added weight on the tailpiece, so I reached over and removed it. "Who turned off the speaker!?", he exclaimed. It can make a difference.
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Nick Kitchener
- Posts: 112
- Joined: Mon Oct 30, 2023 5:37 pm
Re: archtop tail gut material - nylon / steel / kevlar?
Food for thought.