Showing posts with label Scully Lathe. Show all posts
Showing posts with label Scully Lathe. Show all posts

Wednesday, October 13, 2010

Scully Lathe

Just file this under irrational techno lust. The skully lathes are so cool.

The above may actually be a Neumann lather.

Thanks for the comment wbhist.

The Scullys of the 1950's and '60's (as on the 4th and 5th pictures shown) are my preferred variant. Lead-in grooves had spacing dimensions of 32.3125 and 7.625 lpi, with some having a "medium" spacing of 15.583333... lpi and most others' "medium" spacing being 14.7291667... lpi. Such lpi dimensions also applied to "spread" grooves that transported between one "band" and another on an LP record; and the 32.3125 and 15.583333... (or 14.7291667...) were used for "catch" grooves that came after the lead-out but preceded entry into the locked groove (this, I'm told, for the activation of automatic record changers). As for lead-outs, depending on what lathe was used by which studio, there were "slow" and "fast" moving turns, grouped as follows: 4.62 and 2.3 lpi; 4.17 and 2.14 lpi; 3.92 and 2.04 lpi; 3.83 and 1.98 lpi; 3.69 and 1.92 lpi; and 3.48 and 1.83 lpi. Those are the lathes with the knobs that turned anywhere from 70-400 lpi, or 105-600 lpi, or 140-800 lpi. Lathes as so constituted appear to have been manufactured as early as 1950, so I'm told.

The earlier lathe with a gear box as at photo bottom, its design dated back to c.1938. The lpi dimensions as shown were 88, 96, 104, 112, 120, 128 and 136 lpi. In this configuration, there were other sub-classifications. Columbia in New York had a lathe (in use from c.1939 up to August 1966) that had groupings of 150.1875, 163.6875, 177.1875, 190.6875, 204.1875, 217.6875 and 231.1875 lpi; while Aardvark Mastering's ancient Scully's finer grooves are 178, 194, 210, 226, 242, 258 and 274 lpi. Then there are even finer groups, with the "coarse" being 132, 144, 156, 168, 180, 192 and 204 lpi (plus, on Columbia's aforementioned cutter, 225.28125, 245.53125, 265.78125, 286.03125, 306.28125, 326.53125 and 346.78125 lpi).

As to the lathe on the top photo as originally on the cover of that Electronics World magazine: Looks suspiciously like a Neumann AM-32 to me.