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.
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.
Of course you are correct. The presence or absence of a lead screw
does not a secondary operation machine make.
However, since he's talking about a Hardinge lathe, I'm guessing that
what he's referring to is a TFB lathe. Maybe he'll come back and
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)
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.
The Hardinge lathe that is termed a "second operation" lathe has an 8
station turret in place of the typical carriage, and no tailstock. They
are not an engine lathe, and lack a lead screw. They have thread cutting
ability thanks to master thread collars and followers. They are a very
accurate machine when in good condition.
Parts to be machined are generally either pieces of stock already cut to
length or have the first side machined on another machine, turret lathe or
engine lathe, have been parted to rough length and are chucked or otherwise
held to have the parted off side, or second side, finish machined. These
machines are also known as chuckers. They are inclined towards production
work, as are turret lathes. They would not be a good lathe to own without
an engine lathe due to the greatly restricted capabilities of such machines
for general machine work. You can take a look at one here:
Back in my apprentice days of a gearing company I used to work for I
started in the lathe department. A part was made on a bar lathe. This
is a lathe with an attachment that held a length of bar stock to make
the part. Lets say there are a couple of different diameters to turn
on both ends of the part. The part would first have the dia. turned in
the first operation. It would then be parted off with a cut off tool
to the length needed to make the part the right length plus some
material. The "sceond" operation would then be proformed on the other
end of the part, say like turning it to a specific dia. and maybe a
thread turned on it or a hex put in the end. It would also be trimmed
to the final length the print called for. Thus "second operation"
lathe. any lathe can be set up for second operation. I believe it was
a sales pitch to have a product called "second operation" lathe. They
could sell two lathes instead of one. Just my 2 cents worth.
The six station turret DV-59 (or its predescessor, the DSM-59
split bed) is typically called a second op machine. The chucker
is not usually identified as such, in my experience, and threading
is rarely done on the DV-59, as you say most often on an HC
The DV59 can also be fitted with a real tailstock and
cross slide, and as such is called a toolmakers lathe, although
that term is usually reserved for an HLVH. The tiny
speed lathe with with dovetail bed is almost invariably
called a 'speed lathe.'
Example of a second op machine, with turret and cross slide:
in foreground. That is the older split bed style.
please reply to:
JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com