[78-L] playing vertical disc from metal part

[Michael Biel]

neechevoneeznayou at gmail.com wrote:
>>>> Is it possible to play a metal part to a vertical record with a
>>>> bifurcated stylus? I cannot think of any reason why it should not be
>>>> doable, but I have no experience with these things. Would appreciate
>>>> hearing from the list.

On 4/27/2012 1:16 PM, Michael Shoshani wrote:
>>> Interesting question. I would think that bifurcated styli are designed
>>> to respond laterally, since they are split down the middle.

They are not really just a stylus split down the center.  They are
formed from two regularly pointed styli, and are set for the point to
contact the ridge sides at about where a regular stylus would hit a
groove wall.  They are not riding like an inverted V on the pointed
ridge of the metal negative. 

Whether a vertical stamper could be played would probably rely on the
groove shape.  Many vertical grooves get wider as they get deeper, and I
think that a forked stylus could ride on it being pushed up and down by
the walls, not the very top of the ridge.

>>> Presuming you're playing a stamper or matrix rather than a mother?
>>> MS

A mother is a metal positive and would be played by a normal stylus. 

From: "neechevoneeznayou at gmail.com" <neechevoneeznayou at gmail.com>
>> I would assume a stamper. Do higher parts turn up? I was under the 
>> impression that one, forget which, would be destroyed in the plating 
>> process?   joe salerno


From: "Robert M. Bratcher Jr." <rbratcherjr at yahoo.com>
> The master laquer or master wax is badly damaged or distroyed as it
> gets stripped from the mother. If not then it's still not used to
> make another mother after that.

No, there are instances where they have made more metals from original
masters that were undamaged when pulled.  Probably not for classical,
but maybe for popular or ethnic.  Quality control was very low for
ethnic -- for example I find a very high percentage are not centered
well, especially on Columbia but occasionally on Victor.

Once you get into the metal form you can usually make many platings from
metal positives to get mothers, and many platings from each mother to
get many stampers.  This would also be the case for the modern Direct
Metal Master DMM process which cuts a groove on a copper-plated metal
instead of a lacquer.

Mike Biel  mbiel at mbiel.com