As allan notes
there were several SB Revisions or Models.
was the “O” Model, Steve Wells believes the “O” stands for
The there was
an “N” Model (Perhaps N=New)
were “R”, “S” and “T”
Here are some
comments from Dennis Turk on the “N” Model
will tell you that the N was a breed of cat all its own. The saddles
will not interchange with a bed for an O R S and T lathes. The apron
from an N will not bolt onto any of the other series saddles. The
quick change gear box is different as the lead screw exits the box in a
different place as required buy the apron gears. Also the end
bracket for the lead screw is different and will not
Here are some
comments from Steve Wells.
the first mention we see of Series O and N in catalogs seems to be early
1931, at which point they began to retroactively refer to the older lathes
as 'O'. I have always assumed that series 'O' was short for 'Old' and was
necessitated by the introduction of the Series N, for
series letters and the model numbers can be a bit confusing at times, I
attempt a simple approach to the “basic” ID of some of the models for
what is an O series lathe? This is the “Original O’Brien designed
it by the O for O’Brien or O for original, in 1931 SB stated they
making this series since 1906, and now they had developed a “New”
had a new apron and several other improvements, they called this New
“N” design, it had the “New double wall friction clutch apron” and other
It had a push-pull knob for the power feeds, very easy to tell the
the “(O)ld” star feed knob and the “(N)ew”
do you see a pattern in the way they advertized? Yes, they did use the
words like that.
when the New series that was more expensive maybe didn’t do so well in the
introduced another series in 1934, called…the “R” we can tag it as
it had the more modern feed shifter and other changes, I won’t go into all
remember the “revised shifter apron” for “R”. For a few years these three
series were all made at the same time
you can see an O, N and R series in the mid
the same early thirties they also were trying to capture the lower price
market and cope with the loss of sales
the depression era, we see them develop the 8 inch Junior, the 9 inch
Toolmaker, and the “Workshop series.
also still had the “Junior” lathes, which were just a basic change gear
lathe with lead screw feed only, they had
type of lathe for many years prior, in the O type lathes, in about 1926
the coined the “Junior” advertising to
there were “Juniors” in 9, 11, 13, and 15. Junior series sounds so much
better than “Cheaper Model”.
carried the Junior description to at least 1940-41 and even the heavy tens
had a Junior partner. Where
of the confusion comes in, is not realizing that the models are very
similar, as far as beds, headstocks, tailstocks
the Juniors have the same beds and other sundries as the regular letter
series lathes, they just have the simple
maybe a couple of years behind on the improvement features, they were
designed to be cost effective.
8 inch junior and the 9 inch Toolmaker lost the sales war to the “Workshop
lathe and they were phased out.
were smaller lathes than the letter series, just compare the workshop to
the Heavy Ten, that’s basically the size
are comparing between the letter series and Juniors which we call
“wide-beds” and the smaller lathes.
differences in the development of the Workshop see this
close here and stop rambling, I’ll say that the next series after the “R”
was the T series for “Tool room”, this was still a top
with higher spindle speeds, it replaced the N and R series, so now it is
easy to tell the difference between the last letter series
was the “Speed series”, “Super Finished Spindle” “Side oiling Headstock”
“Spindle Speeds increased for carbide
how many S’s you can find in the
So this is as
much as I know or can remember.
I can querry
Steve and ask when the changes in the headstock occued
i've looked at
a few of the older 9" machines. There was a headstock redesign around 1929
or so. The ones before that seem to have little or no place for felt in
the bearing, but generally have a felt plug in the bottom of the oil cup.
The ones after that seem to have a more defined slot in the top bearing,
and more clearance along the parting line. In most cases, those have had
some evidence of felt in those areas.
On Tue, Jun 9, 2015
at 8:53 AM, hotrodjap@... [SOUTHBENDLATHE] <SOUTHBENDLATHE@...>
here either but I see no place for felts. Apparently that large washer
shown is the thrust bearing as it wears against the end of the spindle
bearing. Just curious if the takeup nut has a shallow hole in it that
holds the fiber washer and keeps it stationary like the ones on 10L
version.I bought a used takeup nut and it had a steel washer with it to
use in conjunction with the takeup nut rather than a fiber washer and was
probably meant to be used on a 10L with a brass spindle bearing rather
than on mine which is all cast iron.