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Sep 30, 2023 - 11:38:34 AM
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96 posts since 7/7/2014

In Walter Carter’s book "Gibson Guitars; 100 Years of an American Icon" (1994), I wrote the chapter on Gibson Banjos. In that chapter I stated that Gibson engineer George Altermatt invented the ball-bearing tone chamber and was awarded U.S. Patent 1,678,456 for the tone-chamber’s design. During the past two years, while doing the research for my most recent book, "The life and work of Lloyd Allayre Loar," I discovered that it was Lloyd Loar who was responsible for the non-spring, and later spring-loaded ball-bearing tone chambers - not Altermatt. In a somewhat questionable move, and at a rather early period in Loar’s employment at Gibson, the company had Loar transfer his rights to the ball-bearing design to Gibson on August 18, 1922.

Loar’s last day at Gibson was Friday, October 17th, 1924. Nine months later, on September 28, 1925, George Altermatt filed for the U.S. Patent for the spring-loaded ball-bearing tone chamber that Loar deigned. As result, in my opinion Altermatt was just a surrogate, and Loar should get the full credit!


Sep 30, 2023 - 12:10:22 PM

15508 posts since 10/30/2008

Thanks for this information.

Sep 30, 2023 - 12:49:14 PM



1826 posts since 4/12/2004

If that's true, it was a fraudulent patent.

Did you find anything in your research that provided an explanation of the intended purpose of the ball bearing design? If not, do you have an opinion about the intended purpose?

Sep 30, 2023 - 1:19:22 PM

96 posts since 7/7/2014

Hi Wayne...
Yes, I am concerned about the "fraudulent" aspects, too. A patent should be in the inventor's name. But, of course, it is now 100 years after the fact, and none of the principals are around any longer to argue the point. Although paragraph 5 of Lewis Williams' 3-page letter to Loar of January 13, 1921 puts Loar in charge of patent applications, the Assignment of August 18, 1922 took this one away from him.

As to the "purpose" I believe you are referring to the contribution of each of the parts to the instrument's sound (?). The opening second paragraph says "The main objective of the invention is to provide a banjo in which the volume of tone is greater than that of the well-known or standard types of banjos and is at the same time is of pleasing quality." (By "volume" he is referring to amplitude, not cubic space.)

The drawing and body of the patent (three pages) speak to the parts and what they are. The 15 claims of the patent only refer to the parts and how they fit to or work with each other. There is no other description of HOW the parts work or HOW they contribute to greater tone or amplitude.


Sep 30, 2023 - 2:34:13 PM
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1352 posts since 11/10/2022

laughTheres some good news though. I am somewhat new to banjos, have never heard of Altermatt, and am under the impression that Loar invented the BB system from my searches through bho archives. So history seems to be on track at least at the bho.

Sep 30, 2023 - 8:25:47 PM

12929 posts since 10/27/2006

Originally posted by RB3

If that's true, it was a fraudulent patent.

Did you find anything in your research that provided an explanation of the intended purpose of the ball bearing design? If not, do you have an opinion about the intended purpose?

LL wrote extensively about his discoveries and inventions. I don't know if anyone has posted it in one place, however.

Much of his writing presents opinion as scientific fact but you do get to know what he thought and why. 

Edited by - mikehalloran on 09/30/2023 20:26:14

Oct 7, 2023 - 5:31:03 AM
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8473 posts since 9/5/2006

i was also told this spring ball bearing design was to help keep head tension at its proper setting to allow for weather changes for the hide heads of the day.

Oct 7, 2023 - 5:46:24 AM

4831 posts since 9/12/2016

I've never been up close with a ball bearing--but do wonder if they possess a reverb effect

Oct 7, 2023 - 8:32:43 AM

644 posts since 2/21/2005

There is a 4 part video presentation by Joe Spann and George Gruhn on YouTube from one of Ben Clark’s banjo gatherings. Part 2 is especially relevant to this discussion as it contains Spann’s opinion of Loar and his role at Gibson. Spann is not a fan.

Oct 7, 2023 - 8:39:45 AM

96 posts since 7/7/2014

Terry... I've heard that as well, but I don't believe it was the intended purpose of the spring-loaded ball-bearing design. I do believe that Loar's focus was on developing a very resilient support for the head with a goal of improved sustain and amplitude.

Tom... My favorite go-to banjo is this RB-3 ball bearing. I've never noticed a "reverb effect" but ball-bearing banjos typically do have a hollow-ish sound (which might be what you are referring to) that is not attributed to arch- and flat-top banjos. But clearly the banjo has great sustain and clarity. The spring-loaded head is sensitive enough that a light attack easily brings it to life, and when driven hard, it has very impressive amplitude. And, for us old geezeers, the banjo is lighter than one with a cast tone chamber and is easy to carry around.


Oct 7, 2023 - 1:01:07 PM



79 posts since 1/26/2008

My theory is that the ball bearing was a response to Paramount mounting a ring on rods, or Fairbanks mounting a ring on a scalloped ring. Ball bearings just seemed better than rods or scallops. I think the spring we to make sure that none of the ball bearings got loose and rattled. Just my guess.

Oct 8, 2023 - 5:12:44 AM



2528 posts since 11/29/2005

The ball bearing spring is super duper stout, I don’t see how it could compress much, and there are lots of them. I have a 26 style 3.

Oct 8, 2023 - 5:20:43 AM
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2188 posts since 4/18/2007

Thank you for your research and information,

Oct 8, 2023 - 12:07:59 PM



932 posts since 3/3/2007

Here is a TB-5, serial number (not FON) 70110-1, possibly the first TB-5 that Loar made. It dates to 1922, just before the release of his renouned F5's. Its a trapdoor, snakehead,10 1/2 in rim. The photo shows the tubular steel tone ring sitting on ball bearings, a bit hard to see, but I didn't want to take it apart! I know of 2 other TB-5s with 701xx numbers, and a GB-5 with 704xx number, which I'd love to see. Can't wait to read your book Roger.

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