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  1. #1
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    Default Edison Phonograph Thread

    A good friend collects old sound producing play boxes and has several Edison style phonographs.
    Where possible, the boxes are brought back into operational status, and it is fascinating when he demonstrates a horizontal wax cylinder.

    The task he has asked me to do is screw a small holder of some sort into a larger 'thinga-ma-jingy'.
    Perhaps it is the holder for the pick into the end of the trumpet.
    The photo shows the two items.

    Phonograph compr.JPG

    The thread is a puzzle.
    It is about 0.060" diameter.
    It has been compared to a UNC 0/80 tap, specified as 0.060", but it is finer.
    Tried a ISO 1.4/0.3 tap, about 86 tpi, but it is finer than that also.

    Cannot see into the hole well enough to see if its threaded.

    Edison was a cunning businessman, perhaps he used a proprietary thread.
    Any suggestions ?

    Keep well,
    John.

  2. #2
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    Default

    Have you tried BA threads? They were used on instruments all over. After that as you suggest, you are looking at 'specials'

    Michael

  3. #3
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    Default

    If it is not a special thread used by the manufacturer I would hazard a guess that it might be a Thury thread. This was a Swiss thread widely
    used in the late 19th century/early 20th century mainly by clock makers and instrument makers. The phonograph application would be similar to these.The BA series of threads are derived from these Thury threads and should be interchangeable.
    British Association Screw Threads | BA Thread Chart | Apollo International

    It looks as though an 11BA thread might fit your description. BA dies are still available, but 11BA is fairly uncommon. Two old stock ones left here though @ $19 each.
    https://www.minibearings.com.au/stor...dbt015b/?v=943

    Frank.

    Michael posted while I was typing this.

  4. #4
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    Default

    Michael,
    Thanks for the comments.
    BA thread is unlikely considering it is Edison in the US, possibly predating the introduction of BA threads (1903 in the UK).

    11 BA is 0.059 " dia and 81.9 tpi, so not a match.
    12 BA is 90.9 tpi, but only 0.051", so also not a match.

    I will try and sort out just where the small holder was acquired, then hope I can get a specification/description/guide as to what it is.
    I live in hope that if I can penetrate the phonograph collectors cadre, I can define the thread,

    The hole will let a 1 mm drill through, but not a 1.1 mm, so tapping to the screw thread is an option (if I can get a tap for that size).

    Keep well,
    John

    franco posted while I was typing.

  5. #5
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    Default

    If you are talking 1mm, you may find this would suit, https://www.mektronics.com.au/bernst...1-pieces.htmlI have no Idea where you would buy separate taps, I use these and sometimes one like this for jewellery Makinghttps://www.jewellerssupplies.com.au/product/26907-thread-cutting-screwplate-set-0-8-2-0mm

  6. #6
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    melbourne australia
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    Default

    Quote Originally Posted by electrosteam View Post
    I live in hope that if I can penetrate the phonograph collectors cadre, I can define the thread,
    John,
    Wouldn’t your friend be the person to help you with that? Surely he must have contacts?

    I can’t help with the thread I’m afraid. Sounds very unusual.

  7. #7
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    May 2015
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    Richmond
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    Quote Originally Posted by electrosteam View Post
    Michael,
    Thanks for the comments.
    BA thread is unlikely considering it is Edison in the US, possibly predating the introduction of BA threads (1903 in the UK).

    11 BA is 0.059 " dia and 81.9 tpi, so not a match.
    12 BA is 90.9 tpi, but only 0.051", so also not a match.

    I will try and sort out just where the small holder was acquired, then hope I can get a specification/description/guide as to what it is.
    I live in hope that if I can penetrate the phonograph collectors cadre, I can define the thread,

    The hole will let a 1 mm drill through, but not a 1.1 mm, so tapping to the screw thread is an option (if I can get a tap for that size).

    Keep well,
    John

    franco posted while I was typing.
    If you know someone with a Optical Comparator you could most likely come up with the pitch without straining the eyes or best guessing too much.

    D

  8. #8
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    Quote Originally Posted by OldRustyToolie View Post
    If you know someone with a Optical Comparator you could most likely come up with the pitch without straining the eyes or best guessing too much.
    I can do that at work if you run out of options

  9. #9
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    Richmond
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    Quote Originally Posted by elanjacobs View Post
    I can do that at work if you run out of options
    I just posted to remind John that we can check it here for him. We are only 25 minutes apart so no probs checking, we just have to make a time. He must have forgotten about the comparator in my workshop.

    D

  10. #10
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    OldRustyToolie,
    Thanks, I might take you up on the optical comparator, a good excuse to get some of the locals to a lunch.

    Got onto my friend, who told me we are dealing with a "Reproducer" and gluing is not an option.
    The screw must be removed to fit a gasket (of some kind).
    The screw is one of a number acquired from the US several years ago, source now lost.
    He is a member of a forum and will make inquiries.

    Checked the screw against a 12 BA screw.
    About 6 pitches of the unknown = 5 pitches of the 12 BA.
    So, pitch is about (90.9) X 6/5 = 109 tpi.

    Keep well,
    John.

  11. #11
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    Richmond
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    Quote Originally Posted by electrosteam View Post
    OldRustyToolie,
    Thanks, I might take you up on the optical comparator, a good excuse to get some of the locals to a lunch.

    Got onto my friend, who told me we are dealing with a "Reproducer" and gluing is not an option.
    The screw must be removed to fit a gasket (of some kind).
    The screw is one of a number acquired from the US several years ago, source now lost.
    He is a member of a forum and will make inquiries.

    Checked the screw against a 12 BA screw.
    About 6 pitches of the unknown = 5 pitches of the 12 BA.
    So, pitch is about (90.9) X 6/5 = 109 tpi.

    Keep well,
    John.
    Would be great to catch up John. Miss the monthly lunches. St Marys still no chew n spew. What about Penrith RSL. Still closed?

    D

  12. #12
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    I think I have identified the thread.

    Horological Waltham #1 is 0.059 " and 110 tpi.

    Now to find a tap.

    Keep well,
    John.

  13. #13
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    Quote Originally Posted by electrosteam View Post
    Now to find a tap.
    AHAHAHAHA

    Seriously though, good luck; I reckon you'll either have to make one or have one made, if you're lucky a watchmaker might have one. Do you know the angle?

    As a side note, it would seem that Waltham threads are specified in metric diameter and imperial pitch for some reason https://pocketwatchdatabase.com/guid...olof-ohlson/92

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