Ed Huntress wrote:
"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

There were quite a few Rivett second operation lathes at the last large
auction I attended, they went for as little as $50.