[Phono-L] Some questions aboutOrthophonicreproducers--restorability, reproductions

Dan-K edisone1 at verizon.net
Thu Jan 31 06:25:45 PST 2008


Wheel-bearing grease worked for one of my Orthophonics!


----- Original Message ----- 
From: "Greg Bogantz" <gbogantz1 at charter.net>
To: "Antique Phonograph List" <phono-l at oldcrank.org>
Sent: Thursday, January 31, 2008 4:42 AM
Subject: Re: [Phono-L] Some questions 
aboutOrthophonicreproducers--restorability, reproductions


    The desired motion of the bearing balls is infinitesimally small.  The
needle tip is moving maybe a few thousandths of an inch peak to peak at
most.  Translated to the rotational motion at the bearing, this is mere
thousandths of a degree.  The later Victor design was to use oiled leather
as a packing ring.  The use of any kind of elastomer more than accommodates
the tiny motion of the bearing balls.  It is far more important to keep the
balls set tightly in the space between the needle bar pivot pin and the
outer bearing race.  Any slop in this space will result in a rattling noise
in the audio.  Any kind of elastomer used as a packing ring is more
desirable than using a stiff washer as it accommodates the tiny variations
in the ball diameters and the race diameters which can cause the individual
balls to sit in the tapered race area at slightly varying depths and reduces
this bearing slop to nil.  The minuscule motion of the balls is more than
accommodated by the flex in the elastomer.

Greg Bogantz



----- Original Message ----- 
From: "Ron L'Herault" <lherault at bu.edu>
To: "'Antique Phonograph List'" <phono-l at oldcrank.org>
Sent: Wednesday, January 30, 2008 10:27 PM
Subject: RE: [Phono-L] Some questions about
Orthophonicreproducers--restorability, reproductions


I've wondered about the use of rubber against the ball bearings.  Wouldn't
that interfere with their rotational function?  Wouldn't a Teflon or brass
ring backed by rubber be a better option?

Ron L

-----Original Message----- 



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