Thatcher,
That's essentially what I am now doing. The present design is a press
fit of the needle shank into the hole (deep well, actually) in the needle
bar. But the fit must be tight to prevent rattling. This makes the
machining difficult, but more significantly, it makes the needle exchange
difficult because you must use pliers, tweezers, or some similar tool to
hold both the needle bar and the needle shank for both insertion and
removal. Not user-friendly. Specialized tools and/or jigs could be
furnished to make the job easier, but it's still a tedious task. A friend
of mine has experimented with a similar design. His solution is to glue the
needle shank into the needle bar. That works, but getting the worn needle
out of the needle bar is a b*tch. He gets around this by using the
"semi-permanant" osmium Pfanstiehl needles that were popular in the 1940s
and can last for several playings. I don't agree with this because these
needles are too hard, as I've commented before, and must be worn in over
several playings on junk records to form their flats. He removes the needle
by heating the glue with a soldering iron to cause it to flow. Still, very
tedious.
Greg Bogantz
----- Original Message -----
From: "Thatcher Graham" <thatcher at mediaguide.com>
To: "Antique Phonograph List" <phono-l at oldcrank.org>
Sent: Wednesday, February 13, 2008 3:16 PM
Subject: Re: [Phono-L] threaded needles
>
> As an engineer I could not help but to fixate on this "threaded needle
> idea". I agree that threading needles solves the mass issue hence the
> instinctive appeal, but the difficult manufacture is equally discouraging.
> As an alternative, have you considered a sabot?
>
> -Thatcher
>
>
>
> Jon Noring wrote:
>> Greg wrote:
>>
>>
>>> Threading the needle shank and having it screw into the needle bar
>>> is an
>>> option. I hadn't considered that before, but it would pretty well solve
>>> the
>>> extra mass problem. But it would make the needles pretty involved to
>>> manufacture. I'll keep it in mind.
>>>
>>
>> Yes, it would be involved if all the needles are threaded by hand or
>> in small numbers, especially at the diameter being considered.
>>
>> It is intriguing to consider using a very fine threaded rod, if even
>> manufactured in the desired material(s). One would have to grind and
>> polish to create the tip geometry.
>>
>> Which brings up the idea that if a needle is to be especially
>> manufactured, one could consider tipping it with a different material
>> that can be specially shaped (such as spherical or elliptical with
>> no sharp edges at all. It is my understanding that most damage to
>> grooves is due to a tip which is no longer smooth. Maybe the tip could
>> be made from a material of the same hardness as the "grit" used in
>> shellac discs (is it corundum?) to wear down the needle.
>>
>> Just thinking outside the box...
>>
>> Jon
>>
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>>
>
>
>
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