[78-L] playing vertical disc from metal part

Gerald_Fabris at nps.gov Gerald_Fabris at nps.gov
Mon Apr 30 11:04:09 PDT 2012

On 04/27/2012 12:44 PM, neechevoneeznayou at gmail.com wrote:
> Is it possible to play a metal part to a vertical record with a
> bifurcated stylus?

I've done some test transfers of negative metal Edison Diamond Discs.
Edison used the term "mold" for negative metal parts, using disc molds in 3
stages: "Master Mold", "Second Master Mold", and Working Mold".

Yes, it is possible to play a Diamond Disc mold using a bifurcated stylus.
I've had some good results.  I had 3 sizes lent to me for testing, and 2
sounded wrong, but one sounded very good.

BUT, bifurcated styli are designed for lateral grooves.  As far as I know,
no one has ever made a bifurcated stylus designed specifically for a
negative vertical groove.  With a vertical groove, a stylus must ride along
an ever-changing groove width and depth.  With lateral, the groove is
basically a constant width and depth.  So, the geometry is more complex for

Jerry Fabris, Museum Curator
Thomas Edison National Historical Park
National Park Service
United States Department of the Interior
211 Main Street
West Orange, New Jersey 07052
tel:  (973) 736-0550, ext. 48
fax: (973) 243-7172

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