Subject: Re: lathe differences

From: [email-masked] (gary preckshot)
Date: 17 Nov 1993 00:38:23 GMT

Well, somebody had to do it, so I suppose it might as well be me.  I
cheated and looked "engine" up.  Ya got yer choice of
1) a machine for converting thermal energy into force and motion
2) a locomotive
3) a fire engine
4) any mechanical contrivance
5) an instrument of war
6) an instrument of torture
Take yer pick.

In article <[email-masked]>, [email-masked] (John Kopf,
X6305) wrote:

> >A toolroom Lathe is a lathe with a short bed.

I think I'll look this up in Kent's or Machinery's Handbook.

> >....s.  ENGINE LATHES are those that the motor drives a transmission 

> >O.K. ?

Maybe not.  According to the above, lathes are engines because they're a
mechanical contrivance or they're engine lathes because they're driven by
an engine.  In modern times this seems like a specious distinction.  I used
to think it meant they had no lead screw, but since then I've seen "engine
lathes" advertised that had lead screws and all the feeds you could want. 
I've also seen lathes advertised as "geared head", so the geared
distinction appears to be separable from "engineness".  Maybe it used to
mean something, but no longer does?  Or maybe they're no longer used as
instruments of war or torture.  Come to think of it, I've never heard the
expression "stretched on a lathe".

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From: [email-masked] (f.w.kerfoot..iii)
Date: 17 Nov 93 14:22:21 GMT

>From article <[email-masked]>, by [email-masked] (gary preckshot):
> ....

I also did some research in my "library" last night. I checked several
textbooks on machining techniques, and a variety of other books. Most
didn't define "engine lathe", but seemed to use it as the default,
in that if it wasn't something else, like a turret lathe, then it was
an engine lathe. One older book, called "Rogers Machinist's Guide"
states that there are several common definitions, and mentions 3.
First, a lathe with power, as opposed to a foot lathe. Second, a
lathe with power feed on the x-axis, and third, a lathe with power
feed on both axes. Machinery's Handbook did not have a definition.

I also looked more carefully at the 1958 South Bend catalog. For all
of their larger lathes (16", 14.5", 13", 10") they divide each size
into two types, "toolroom" and "engine", thus apparently following the
definition that it is an engine lathe if it is not some other type.
As I discussed previously, a South Bend toolroom lathe (in any of the
sizes) was a more fully equipped lathe. Although I didn't say so last
time, some of the included options are focused at improved accuracy,
like a precision lead screw. All of these South Bend lathes in 1958
were belt driven, so the idea that "engine" means "geared head" seems
off the mark. Also, in the 10" size, South Bend offered both floor
models and bench models in both the engine and toolroom categories,
so that is apparently not related to the distinction. Also, someone
suggested bed length. South Bend offered the toolroom version in
essentially the same range of lengths as the engine version. South Bend
continued to use the toolroom versus engine distinction for their
belt driven lathes in catalogs from the 1980's as well.

Interestingly, for South Bend's smaller lathes, including the 9"
and the 10-K (or "light 10"), the term engine lathe is not mentioned.
The options are "toolroom", and Model A, B or C, where the latter
are QC gearbox, manual change gears with power cross feed, and manual
gears with half nuts only on the carriage. The term "engine lathe"
never appears in the text for these lathes either.

In summary I suspect that the original poster should assume that a
lathe labeled a toolroom lathe is one which either the seller or the
original manufacturer thinks is a premium lathe in some way
(accuracy or equipment), and that an engine lathe is one that the seller
can't justify (or hasn't thought of) calling a toolroom lathe.
Overall, go by visible condition and equipment, not by the name the
seller applies.

Frank Kerfoot
[email-masked]

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From: [email-masked] (Michael J. Edelman)
Date: 17 Nov 1993 15:53:13 GMT

In article [email-masked],  [email-masked] (f.w.kerfoot..iii) writes:
...
>like a precision lead screw...

A glance at Blue Ridge's current catalog reveals that the current difference
between South Bend 'engine' and 'toolroom' lathes does indeed have to do with
precisions. The Toolroom models come with a collet chuck and collet rack, as well
as a 'precision' faceplate.

--mike