Pre-stretching tailgut

[dpappas]

Hello MN!

I have a tailpiece that I’m going to try out on my violin.  It’s a little shorter so it might increase my after length since my current tailgut is pretty short already and there is no room for adjustment.

I’m suspending the tailpiece by a few old strings and have a 10 lb weight tied to the tailgut to “pre-stretch” the nylon tailgut.  I know David Burgess has a jig to stretch cello tailgut, so this is a makeshift version of it.  

My goal is to minimize the stretch so when my luthier swaps it out the length will be close to what I want.  Of course there is wrapping around the button and settling over the saddle as well, I’m just trying to eliminate a variable.  

Does anyone else else do this?

 

[Don Noon]

10 pounds is way below the tension of a string set, so I don't think you're doing all that much.

I posted a photo of my tailgut pre-stretcher in this post, at the bottom.

[dpappas]

Don,

that’s a great rig, thank you.  I figured 10 lb is not close enough but tonight it was about testing the rig itself.  I need to figure out the loading and add weight. 

[carl1961]

4 hours ago, Don Noon said:

10 pounds is way below the tension of a string set, so I don't think you're doing all that much.

I posted a photo of my tailgut pre-stretcher in this post, at the bottom.

Awesome tool, as always you come up with the neatest tools, what is the pounds you set the jig at? and do you gradually tighten and how long have you learned to stretch it before you happy?

[Don Noon]

I have only used the pre-stretcher once so far, and then shortly before I was going to use the tailgut, my wife needed the luggage scale to take on a trip... so, not a good test.

Another annoyance is that the scale resets every time you turn it on, so to get a good reading of the actual tension, it needs to be completely loosened.  It's impossible to see how much the tension relaxes over time.

I put on more tension than the gut will see in use, generally 60 lb would do it.  If you have one end of the gut fixed and load the other end, then you'd only need 30 lb.

[dpappas]

Don,

 

as always, you are a great source of information.  

 

Dimitri

[Bill Yacey]

Is it necessary to pre-stretch the nylon tailgut? It seems to settle down fairly quickly in my experiences. Natural gut is a different story.

[David Burgess]

25 minutes ago, Bill Yacey said:

Is it necessary to pre-stretch the nylon tailgut? It seems to settle down fairly quickly in my experiences. Natural gut is a different story.

On violins, the nylon tailguts can settle down rather quickly.

On cellos,  my pre-stretching regimen also  resulted in stretching in the threaded region, so the thread pitch between the the nut and and the nylon no longer matched. The outcome was that shortening the length would screw up the threaded portion of the nylon. So I no longer use the Sacconi-type tail adjusters on cellos.

This will eventually happen on violins and violas too, but it takes a lot longer.

[The Violin Beautiful]

I’ve been using Kevlar cord for new setups lately. We had a number of cello guts fail at the nylon threads. There were also some violin customers who came in complaining about the violin slipping out of tune during playing; it turned out the tailguts were beginning to fail on those, too.

The Sacconi guts are still hard to beat for ease of installation and cost, but I’m moving away from them on nicer violins, on which I can spend a few extra minutes tweaking things. 

[Bill Yacey]

37 minutes ago, David Burgess said:

On violins, the nylon tailguts can settle down rather quickly.

On cellos,  my pre-stretching regimen also  resulted in stretching in the threaded region, so the thread pitch between the the nut and and the nylon no longer matched. The outcome was that shortening the length would screw up the threaded portion of the nylon. So I no longer use the Sacconi-type tail adjusters on cellos.

This will eventually happen on violins and violas too, but it takes a lot longer.

Perhaps the thing to do is thread the adjusters on as far as they will go, stretch the tailgut, and then adjust to length. This would pre-stretch the majority of the length, and still maintain the thread pitch. After adjustment to length, there might be a little more stretch taking place, but it would be minimal, I would think.

Edit: As a side note, I got some nylon tailguts from somewhere, probably some Chinese clones of the Sacconi type. Initially I thought they were stretching considerable, as the instrument was flat day after day, until I heard a popping noise immediately after re-tuning. Apparently the threaded adjuster sleeves were jumping over the threads in the nylon material. After some checking, it was found they all did the same. All went into the garbage.

[dpappas]

A question for Don:

When you are setting the tailpiece, I know you prefer to minimize parasitic vibrations, and therefore keep the tailpiece as close as possible to the saddle.  I take that to be "as close without touching" but I wasn't sure if that's what you meant, or if there was a specific length you shoot for.

[Don Noon]

1 hour ago, dpappas said:

A question for Don:

When you are setting the tailpiece, I know you prefer to minimize parasitic vibrations, and therefore keep the tailpiece as close as possible to the saddle.  I take that to be "as close without touching" but I wasn't sure if that's what you meant, or if there was a specific length you shoot for.

Even with pre-stretching, the nylon guts stretch after installation.  Maybe there's a fast relaxation.  So I do put them on as short as possible without the tailpiece touching the saddle, and then it gets a bit longer after that.  

If the tailgut is really "as short as possible", I would worry that it would stiffen up the tailpiece torsional vibration and bring it up into a range where it would be noticeable.  But if there's 5mm or more of gut free length, then I have found annoyances with the vibration of the end of the tailpiece.  So I try to keep it under 5mm.

[dpappas]

Thanks for the range, Don!

[Marty Kasprzyk]

I suspect that tail chord stretching is one cause of bridge bending.  Another cause could be string stretching.

In either case gut, or nylon strings and tail chords could cause bridge bending and modern synthetic fiber core strings and tail chords (Kevlar, steel braid) should reduce this problem although it is difficult to make predictions especially about the future.