Double Bass Help with low B breaking double bass

[UTmfUT]

Hey all, earlier this year I had a professional repair my grandfather's 5 string Kay Swingmaster. Love the bass and have loved learning to play, but at the title states, the low B string keeps breaking. It has broken two times total, once with the string installed by the shop (the shop is out of state from me) and the other by a string (for 3/4 bass) I bought and installed.

A little bit of observation and research has led me to the problem, that the string is wrapping around the peg and breaking below the silk top. Can anyone help point out what is the best solution? Is there a way to shorten the string? Is the bass actually a 1/2 size and do they even make 1/2 size low b strings?

Thanks for any help in advance!

 

[Eric Hochberg]

Is the string catching at the nut?

 

[UTmfUT]

It's breaking where the string wraps around the tuning peg. From what I can tell it isn't catching at the nut, but I have been having issues getting the low string to have high enough action to not buzz...and I don't know if the issues are related.

 

[Eric Hochberg]

It's breaking where the string wraps around the tuning peg. From what I can tell it isn't catching at the nut, but I have been having issues getting the low string to have high enough action to not buzz...and I don't know if the issues are related.

Is there a sharp edge at the string hole that's cutting it? Is the string rubbing against the cheek of the pegbox? Is it catching at the bridge?

I don't think the low string height of the B string would cause breakage. Sounds like the bass needs a better setup.

Do you have bridge adjusters?

 

[UTmfUT]

It's breaking where the string wraps around the tuning peg...it's not on the sharp edge of peg, but where it's going down to the neck. This photo is small, but hopefully shows the issue. Didn't want to put the full size image to distort everything.

As I'm very new to this, are there any good set up resources you'd recommend? Thanks so much for your help so far!

 

[Eric Hochberg]

It's breaking where the string wraps around the tuning peg...it's not on the sharp edge of peg, but where it's going down to the neck. This photo is small, but hopefully shows the issue. Didn't want to put the full size image to distort everything.

As I'm very new to this, are there any good set up resources you'd recommend? Thanks so much for your help so far!

View attachment 2873565

Do a search for setup in this forum. Tons of info.

You haven't answered the other questions I've asked, so... Also pictures of the bass would be good. Pegbox, bridge, neck...

 

[Steven Ayres]

All Kay fivers were designed for high C rather than low B. That said, the simplest solution, and the one I use on both my Kay fivers, is to change the peg order so that the low string is at the top of the box rather than the bottom. This reduces the break angle on the nut and the resulting tension in the box. I presume that the nut and bridge are already cut for larger strings, that's really the only setup issue unless you're going for low action, in which case you'll need a fingerboard bevel or two.

 

[UTmfUT]

Do a search for setup in this forum. Tons of info.

You haven't answered the other questions I've asked, so...

The string is not catching at the bridge or at the pegbox and there are no bridge adjusters. From what I can tell, it's the original bridge and the bass was manufactured pre-WW2.

 

[Eric Hochberg]

that's really the only setup issue unless you're going for low action, in which case you'll need a fingerboard bevel or two.

Bevel? or do you mean planing? For low action you need a fairly straight board with little scoop in the mid section.

 

[Steven Ayres]

From what I can tell, it's the original bridge and the bass was manufactured pre-WW2.

If you can share the serial number and model designation, I can confirm the approximate build date and provide you more detail on the model. We'd invite every Kay owner contact us and participate in the Kay Bass and Cello registry at Kaybass.com.

 

[UTmfUT]

All Kay fivers were designed for high C rather than low B. That said, the simplest solution, and the one I use on both my Kay fivers, is to change the peg order so that the low string is at the top of the box rather than the bottom. This reduces the break angle on the nut and the resulting tension in the box. I presume that the nut and bridge are already cut for larger strings, that's really the only setup issue unless you're going for low action, in which case you'll need a fingerboard bevel or two.

I was wondering about this when my dad took the bass to the shop (again out of state). We called around and and got in touch with a member of the local symphony and took it to the place they take their bass. The bass was then set up for a lower register. When I get a replacement string, I will try changing the peg order and see if that helps.

 

[Steven Ayres]

Bevel? or do you mean planing?

Well, both, in that a Romberg bevel is made with a plane. A B requires a pretty deep "scoop."

 

[UTmfUT]

If you can share the serial number and model designation, I can confirm the approximate build date and provide you more detail on the model. We'd invite every Kay owner contact us and participate in the Kay Bass and Cello registry at Kaybass.com.

One of the issues we ran into is, we can't find the serial number. There is the "Kay" signature on the back of the headstock, but we could not find a number. According to family lore, my grandfather bought this in the 1930s just after he turned 18. He passed away nearly 20 years ago and so we can't go to the source.

Where are some areas I can look for a serial number?

 

[Eric Hochberg]

A B requires a pretty deep "scoop."

Not necessarily. Good modern setups can do wonders for easy playing.

 

[UTmfUT]

Looks like I found it...the serial number is 7037

 

[Steven Ayres]

Where are some areas I can look for a serial number?

There's only one place, and that's inside the back opposite the bass-side f-hole. Almost all Kays have a paper tag glued inside as well as the serial number either handwritten in pencil or inkstamped. Pencilled marks can be very light and hard to see, possibly obscured by finishing spray. If you can't find a number, I can likely tell you the specific model from a photo.

I see you found it. Do you have a model designation as well? We have an M-1W #7037, registered years ago to a Jim K. It's not particularly unusual to see the same number on two basses (in one case, even three), but usually these are misreadings.

 

[Ludwig]

If you would like to try a 1/2 B string, there is only one I know of, a Thomastik Superflexible low B for half size.

 

[UTmfUT]

I've got it right here. There's no model designation that I can see:

 

[Steven Ayres]

We have pics of M-1W #7037 on file from 2002, and that one has a build tag inside, so given that yours doesn't and you called it a Swing Master, I'm guessing you have a different bass. Serial-number duplication was not all that rare on the Kay line. Can you share some photos? The members might also like to see some detail on your pegbox in thinking about the problem you presented.

 

[UTmfUT]

Here are some more pics. Previously I was able to play the low B without it buzzing, but where I've adjusted to now it's taught with the fingerboard. I'm about to leave for a week to see my family, but here are some pics to bide the time.

I'm about at the point where I will dig around and try and find a local shop to get it set up. I'd rather not do anything to mess this up. Here are the thumbnails for the sake of post size.