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Bell-Tainter A-Frame Machine Questions

Posted: Sat Aug 12, 2017 10:45 pm
by Rexophone
I have recently been enjoying studying pictures of the Columbia Bell-Tainter A- Frame Graphophones from The Compendium, Hazelcorn's guide, and various Internet sources. I have a few questions for you lucky folk who own such machines.

On the A Frame spring and electric machines I can see the spring-loaded half nut extending upward from the post which keeps the carriage properly aligned, but I do not understand how the half nut engages and how the reproducer is lifted. From some writing I believe that you grab and manually lift the reproducer and this somehow disengages the half nut. Just how does this work?

Looking at patent information and lithographs from the 1880s it seems that both the reproducer carriage and recorder carriage in the earlier treadle models were completely removed when not in use. Is the half nut in these units fixed such that the weight of the carriage when placed on the feed screw automatically engages the half nut?

The Type III treadle machine uses a complex carriage which incorporates both the recorder and reproducer. The recorder can be swung up and down when needed but I don't quite get how the reproducer is engaged. I also don't understand exactly how the half nut is brought into play when either is used.

Sorry for the questions, but I am fascinated with the mechanical evolution of these machines and I'm sure many of us would be interested to know more as well. Since I don't expect to run across any of these at a local yard sale I thought I would ask you all.

Many thanks!

Steve

Re: Bell-Tainter A-Frame Machine Questions

Posted: Sun Aug 13, 2017 11:01 pm
by phonogfp
On the Type C treadles and later Bell-Tainter derivatives (Types C, E, F, I, K, R, U), the trunnion is flipped back to disengage the feedscrew and lift the reproducer from the face of the record. Here's a Type U with its reproducer lowered and raised. Note the half-nut is depressed and disengaged when the reproducer is lifted.
Utrunnion1.JPG
This is a clumsy arrangement, necessitating the removal of a horn (perhaps even ear tubes) prior to raising the reproducer. The ferrule for the horn/ear tubes is pointing backwards when disengaged. You can see why Thomas Macdonald moved to the lift lever centered in a trunnion with no vertical movement for the later models.

George P.

Re: Bell-Tainter A-Frame Machine Questions

Posted: Mon Aug 14, 2017 10:38 am
by Rexophone
George,

Thanks so much for the explanation and photos. There are few photos out there that really made it clear just how the mechanism works. As you say, Mr. MacDonald inherited some curious mechanisms that he had to work with.

Thanks again,

Steve

Re: Bell-Tainter A-Frame Machine Questions

Posted: Mon Aug 14, 2017 11:13 am
by alang
OK, so now I have a stupid question: I assume that the lower bar is the feedscrew and that the half nut is inside that plunger. What I don't see are any threads on the feedscrew (which could be due to my bad eyesight). Or am I missing the point completely?

Thanks
Andreas

Re: Bell-Tainter A-Frame Machine Questions

Posted: Mon Aug 14, 2017 11:23 am
by phonogfp
alang wrote:OK, so now I have a stupid question: I assume that the lower bar is the feedscrew and that the half nut is inside that plunger. What I don't see are any threads on the feedscrew (which could be due to my bad eyesight). Or am I missing the point completely?

Thanks
Andreas
No questions are stupid, Andreas! :)

The feedscrew is hidden inside the upper horizontal sleeve - much like later conventional Graphophones. The lower rod is simply a stabilizer, working in much the same fashion as the slot in Type A/AT/AO/HG/AG (etc.) castings stabilized the trunnions in later machines.

The half-nut has its threads on the upper surfaces, just like later models.

George P.

Re: Bell-Tainter A-Frame Machine Questions

Posted: Mon Aug 14, 2017 11:38 am
by alang
Thanks, I guess I'll need to get myself a Graphophone sometime. I did not know.

Andreas

Re: Bell-Tainter A-Frame Machine Questions

Posted: Mon Aug 14, 2017 12:49 pm
by phonogfp
alang wrote:Thanks, I guess I'll need to get myself a Graphophone sometime. I did not know.

Andreas
Maybe this shot showing most of the gear train from the pulley will make things more obvious.
Uwide.JPG
As for not having any Graphophones in your collection... Shame on you! :lol:

George P.

Re: Bell-Tainter A-Frame Machine Questions

Posted: Mon Aug 14, 2017 4:43 pm
by Rexophone
Andreas,

Not to worry. Although not having a Graphophone is a serious malady, it is entirely treatable by a quick visit to the Yankee Trader page. In fact I am sure there are many well-qualified practitioners reading this page right now who can help work you through this difficulty.

Steve

Re: Bell-Tainter A-Frame Machine Questions

Posted: Tue Aug 15, 2017 3:48 am
by Lucius1958
Rexophone wrote:Andreas,

Not to worry. Although not having a Graphophone is a serious malady, it is entirely treatable by a quick visit to the Yankee Trader page. In fact I am sure there are many well-qualified practitioners reading this page right now who can help work you through this difficulty.

Steve
Start with a single dose: if symptoms do not improve, increase dosage as needed.

Re: Bell-Tainter A-Frame Machine Questions

Posted: Tue Aug 15, 2017 9:06 am
by alang
It's not that I refuse treatment, just haven't found a medication I like and was able to afford yet :lol:

Also, my wife somehow thinks I'm already over-medicated :o

Andreas