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Nov 28, 2020 - 7:09:48 PM
1572 posts since 4/13/2017

I have been fascinated by the ball bearing tone ring system as of lately, and I have some questions regarding its design.

  1. What is the whole purpose for having the tone ring suspended as it is?
    1. How is tone transferred into the rim and into the neck?
    2. What purpose do the springs serve?
  2. Why use springs instead of a solid material?
  3. What would happen if one were to use solid rod in place of the springs and ball bearings?

I'm sure that as I receive answers for these questions, I will have more questions. 

I'm just sort of curious about this whole system. 

Nov 28, 2020 - 7:52:20 PM
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1448 posts since 4/13/2009

This information  in this link is similar to Roger Siminoff's explanation in "How to Set Up The Best Sounding Banjo," but Siminoff places more emphasis on the "floating tone chamber" rather than skin head adjustment.   https://www.banjowizard.com/bbconv.htm

Siminoff's book has been out of print for some time.

Nov 28, 2020 - 8:11:33 PM
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Bill Rogers (Moderator)

USA

24250 posts since 6/25/2005

Do a BHO search on “Ball Bearing Banjo”. You’ll find plenty to read (and plenty to ignore).

Nov 29, 2020 - 1:09:26 AM

Emiel

Austria

9704 posts since 1/22/2003

The springs do not function in keeping the skin head tight. Loys Loar's in idea was (as published by himself) that the tonering could vibrate freely.

Nov 29, 2020 - 6:51:50 AM

RB3

USA

889 posts since 4/12/2004
Online Now

Below is a link to documentation of a patent for a ball bearing tone ring.

Ball Bearing Tone Ring Patent

Nov 29, 2020 - 7:13:40 AM

1705 posts since 6/2/2010

I find it odd that Gibson gets the credit for inventing the ball-bearing tone ring. My ~1915 Lange made banjo has a tone ring that sits up on ball-bearings.

Of course mine doesn't have the springs and or holes in the tone ring so there are enough differences for Gibson to get a patent.

Anybody know if Lange had a patent for a ball-bearing tone ring prior to the Gibson patent.

Nov 29, 2020 - 11:14:09 AM

13612 posts since 10/30/2008

Emil, I'm going to take a crack at the reasons for the spings and washers in the Gibson ball bearing rig.

Imagine the tolerances involved in drilling hemispherical-bottomed holes in which nestle 60 ball bearings (I forget their exact radius but let's call it 3/8" for discussion). All of these ball bearings have to have tops at EXACTLY the right height for the tone tube to sit on top of every one. With no high ones or low ones. High ones will lift or deform the tone tube. Low ones (for instance, the neighbors of high ones) will have a gap. A formula for buzzing and rattling!!!!!

To keep all those ball bearing tops at EXACTLY the same height on an 11" diameter wooden surface you would require (let's guess at precision at least the width of a banjo 1st string, call it 0.010"):

PERFECT planarity of both the top and bottom surfaces of the wooden rim -- variation much less than 0.010". Meaning, where the drill bit is going to work (the top) and where the rim sits on a firm metal surface (the bottom). Then the depth of the bit into the wood as regulated by the drill press has to be fanTASTically precise, again, less than 0.010". This was performed by humans in those days, I'm sure. A hair too deep into the top of the wood rim and you've got a gap and a rattle.

I believe THAT is the reason for the washers and springs. The stiff springs assure that the ball bearings do not sink down "too" far and ruin the "suspension" of the tone tube. The washers provide a tiny bit of "give". Others have reported here that the number of washers per hole varies on any one banjo.

That's my theory and I'm sticking to it.

Nov 29, 2020 - 12:22:30 PM

8050 posts since 8/28/2013

I pretty much agree with Dick Bowman. Earlier Gibsons had a "tone tube" which rested on ball bearings in shallow holes, but had no springs. These were leveled using thin shims beneath the bearings, which had to have been very time consuming and therefore, expensive. Springs would have eliminated some of the fitting process and saved a bit of time and money.

Nov 29, 2020 - 2:14:44 PM

13342 posts since 6/29/2005

Going back 55 years to when I started being interested in banjos, in Harrisburg, PA, I knew some guys who had played in string bands in Philly, like those in the Mummer's parade—there were only skin heads back in their day—plastic heads started around 1958(?) and changed everyting.

They told me that the purpose of the ball bearings on springs was to keep tension on the head in humid weather—these guys marched in parades and played outdoors where it might even rain, so saging heads was a big deal to them—set your action low, then it rains and your head softens—end of game unless you have extra bridges in your pocket.

There is no evidence that Gibson really intended that, and they didn't advertise it, but it was widely believed by string band players at a point in time, and it made sense to me, at least as an idea with merit

Think about it—you can float the tone ring on ball bearings sitting on the rim to minimize the contact with the rim, but why the heavy springs?  it has to be to be pushing up against the bottom of the skin head to maintain the tension, otherwise, there is no point to the springs.

Edited by - Ken LeVan on 11/29/2020 14:24:48

Nov 29, 2020 - 2:20:02 PM
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11012 posts since 10/27/2006

The trapdoor 3 had ball bearings but no springs. The 4 and 5 has springs.

A lot of Lloyd Loar's writings on acoustics fall into the "I think this so it must be true" category and have little to no scientific basis.

Nov 29, 2020 - 2:26:53 PM
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13342 posts since 6/29/2005

quote:
Originally posted by mikehalloran

The trapdoor 3 had ball bearings but no springs. The 4 and 5 has springs.

A lot of Lloyd Loar's writings on acoustics fall into the "I think this so it must be true" category and have little to no scientific basis.


A lot of of banjo conventional wisdom falls into that category.

Nov 29, 2020 - 4:41:47 PM
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8050 posts since 8/28/2013

A lot of everything's conventional wisdom falls into that category.

It does seem more prevalent with banjos, though; tone ring systems and rims in particular.

I hold one person most responsible for conventional wisdom: the well known Ms. Ann Ecdote. She's the one with the most reliable evidence, and scientists and their studies  be damned!

Nov 29, 2020 - 7:37:58 PM
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beegee

USA

22089 posts since 7/6/2005

The self-adjusting feature is just a myth. Gibson was trying to compete with Lange, especially the Paramount system.

The die-springs sat upon a small thick washer with another one on top. There was a small dimple on one side that gave the ball-bearing a slightly larger seat. I have often found paper shims in the bottom of some of the holes, perhaps as a means of leveling the ball-bearings.

I have a spring here that I am trying to find a source for. I just haven't pursued it diligently yet.

Nov 30, 2020 - 9:03:56 AM

11012 posts since 10/27/2006

quote:
Originally posted by beegee

The self-adjusting feature is just a myth. Gibson was trying to compete with Lange, especially the Paramount system.

The die-springs sat upon a small thick washer with another one on top. There was a small dimple on one side that gave the ball-bearing a slightly larger seat. I have often found paper shims in the bottom of some of the holes, perhaps as a means of leveling the ball-bearings.

I have a spring here that I am trying to find a source for. I just haven't pursued it diligently yet.


Good luck with that. Others have tried but I don't recall the results.

Those springs remind me of automotive overhead valve springs but much smaller, of course.

Nov 30, 2020 - 10:01:17 AM

248 posts since 6/15/2006

This is only speculation. I could imagine that at b.b.b. will sound sweet and pleasant, but will also lack power, but I have never been close to one (hope I will some day). I think that a ball bearing with stiff rods instead of springs, would be a little like other banjos with "floating" tonerings - sweet sounding but with some power.
A banjo building friend of mine had made at tubaphone like banjo, but thought it sounded more bright than he had wanted, so instead of having the tonering directly on the wood, he let the ring rest on one layer of rubber from a bicycle hose. He was very happy with the result, and it is still there, but if you ask me I think it is against all rules. Steen

Edited by - steen on 11/30/2020 10:02:27

Nov 30, 2020 - 11:43:03 AM

beegee

USA

22089 posts since 7/6/2005

quote:
Originally posted by mikehalloran
quote:
Originally posted by beegee

The self-adjusting feature is just a myth. Gibson was trying to compete with Lange, especially the Paramount system.

The die-springs sat upon a small thick washer with another one on top. There was a small dimple on one side that gave the ball-bearing a slightly larger seat. I have often found paper shims in the bottom of some of the holes, perhaps as a means of leveling the ball-bearings.

I have a spring here that I am trying to find a source for. I just haven't pursued it diligently yet.


Good luck with that. Others have tried but I don't recall the results.

Those springs remind me of automotive overhead valve springs but much smaller, of course.


They are die-springs. I am just reluctant to send it of to a company to have it matched. The dimensions are not a problem. just the compression factor.

Nov 30, 2020 - 12:04:13 PM

13342 posts since 6/29/2005

quote:
Originally posted by beegee
quote:
Originally posted by mikehalloran
quote:
Originally posted by beegee

The self-adjusting feature is just a myth. Gibson was trying to compete with Lange, especially the Paramount system.

The die-springs sat upon a small thick washer with another one on top. There was a small dimple on one side that gave the ball-bearing a slightly larger seat. I have often found paper shims in the bottom of some of the holes, perhaps as a means of leveling the ball-bearings.

I have a spring here that I am trying to find a source for. I just haven't pursued it diligently yet.


Good luck with that. Others have tried but I don't recall the results.

Those springs remind me of automotive overhead valve springs but much smaller, of course.


They are die-springs. I am just reluctant to send it of to a company to have it matched. The dimensions are not a problem. just the compression factor.


My guess is that Gibson got them as a stock item from some spring company, and they probably had some use at that time—same thing as Martin using sled runner stock from the nearby Flexible Flyer company to make their T-bars for neck reinforcement.

Here's a spring company that grinds the compression springs to exact length—I'd bet a company like that could match the Gibson springs without having a sample in hand if they knew what they were going to be used for and had accurate dimensions to work from.

http://www.fennellspring.com/products.html#compression

Nov 30, 2020 - 12:27:28 PM
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beegee

USA

22089 posts since 7/6/2005

quote:
Originally posted by Ken LeVan
quote:
Originally posted by beegee
quote:
Originally posted by mikehalloran
quote:
Originally posted by beegee

The self-adjusting feature is just a myth. Gibson was trying to compete with Lange, especially the Paramount system.

The die-springs sat upon a small thick washer with another one on top. There was a small dimple on one side that gave the ball-bearing a slightly larger seat. I have often found paper shims in the bottom of some of the holes, perhaps as a means of leveling the ball-bearings.

I have a spring here that I am trying to find a source for. I just haven't pursued it diligently yet.


Good luck with that. Others have tried but I don't recall the results.

Those springs remind me of automotive overhead valve springs but much smaller, of course.


They are die-springs. I am just reluctant to send it of to a company to have it matched. The dimensions are not a problem. just the compression factor.


My guess is that Gibson got them as a stock item from some spring company, and they probably had some use at that time—same thing as Martin using sled runner stock from the nearby Flexible Flyer company to make their T-bars for neck reinforcement.

Here's a spring company that grinds the compression springs to exact length—I'd bet a company like that could match the Gibson springs without having a sample in hand if they knew what they were going to be used for and had accurate dimensions to work from.

http://www.fennellspring.com/products.html#compression


I don't have any way to measure the compression, which is critical to the mission. I will contact them. Thanks

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