"Abrasha" wrote in message
...
George wrote:

Matthew matthewjameslee*yahoo.com wrote:

I have seen the harding tool room lathe and understand that is also
called
a "secind operation lathe" But why is this?

I think you're talking about two different animals. Though the
terminology is confusing.

The Hardinge TFB doesn't have a lead screw and is often called a
Secondary Op. lathe. The HLV-x does have a leadscrew and is generally
termed a Toolmaker's lathe.

But the terms are loosely applied and often used to conceal the fact
that the TFB sells for a lot less than the HLV.

If you are not going to use the lathe for thread turning, then all you
need is the TFB.

George.

I don't think that answers the OP question. I don';t think that having a
lead
screw has anything to do with it.

It is my understanding that a "second operation" lathe is exactly what the
name
implies. It is a lathe on which a different (second) operation is
performed
than on the "first opreation" (there is no such term I think) lathe.

This is done so no setup change is necessary on the first lathe. The
parts to
be machined in the "second operation" are just moved form the first to the
second lathe. Having second operation lathes can save a great deal of
time in
the production of parts.

Abrasha
http://www.abrasha.com

Not quite. Second ops usually are those that don't involve threading or
straight turning. Thus, the lathes traditionally are simpler.

There is some disagreement about what it means today but the most basic form
is the "speed lathe," of which Hardinge made the most desired models, which,
in their basic form, don't even have a carriage or cross slide. They're just
a powered spindle, usually with a collet chuck, that grips the first, turned
end of a piece of work and allows you to perform chamfering on the back end:
the most basic "second op." They also commonly were used for such ops as
lapping and polishing.

As options, you could buy additional features for speed lathes, including
cross slides and so on. A typical set of second operations might be facing
the back end of a part and hand-chamfering (with a cutting tool or a file)
all around.

In its broadest sense, a second operation is any one that can't conveniently
be done in the first chucking of the work. So it can include fancier
operations on the back end. Those ops are called second operations, but a
lathe that's called a "second operation lathe" usually is one designed to do
no more than a couple of clean-up operations.

Ed Huntress