[SEL] Seneca Falls Stud 48 Out

[barry gorman]

                  Barry G.
    The Glorious Hunter Valley
              AUSTRALIA
BarryandPamGorman at bigpond,com
----- Original Message ----- 
From: "Richard Allen" <linstrum55 at yahoo.com>
To: "Stationary Engine List" <sel at lists.stationary-engine.com>
Sent: Monday, January 10, 2005 12:20 AM
Subject: [SEL] Seneca Falls Stud 48 Out


Hi, Alan,

If the lathe is like my old 1940 Atlas 12x60 then the "Stud 48 Out"
refers to two gears stack-mounted on a stud on the back of the lathe
headstock assembly and are part of the gear train that runs down from
the rear of the chuck spindle to the quick change gear box that drives
the carriage feed screw. If you look under the cover at the back of the
headstock in the gear train you will probably find two gears stacked on
one stud, and ONE of the gears does not mesh with any other gear. This
un-meshed gear is EITHER the outer gear and is hanging out in mid-air,
OR is the inner gear, and if you count the teeth on it you will find
that it has either 24 or 48 teeth. This two-gear stack can be removed
and turned over and re-installed so that the 48-tooth gear is either
OUTside or INside. In the OUT position it probably cuts in half the
gear ratio of the carriage feed screw drive and its sole purpose is to
cut 4, 5, 5.5, 5.75, 6, and 6.5 threads per inch using the 8, 10, 11,
11.5, 12, and 13 threads per inch gear shift selections. These numbers
may actually be different but they will be half of one series of
pitches listed on the thread pitch selection table. With the 48-tooth
gear mounted on the outside you will find that the carriage feed screw
turns either twice as fast or half as fast, and is used to select
between the 2:1 or 1:1 ratio, hence the "Stud 48 Out" instructions
associated with the thread selection gears. 

Depending on the gear box scheme that the lathe uses my above
instructions may be the exact opposite of the way it is actually set
up, but you can figure that out. OR my whole premise is wrong (but I
hope not!).

Rich Allen

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