Subject: Re: Lathe Types

From: [email-masked] (James Kirkpatrick)
Date: 22 Nov 94 10:44:13 MST

In article <[email-masked]>, [email-masked] (John W Bottoms) writes:
|>I wanta get lathe'd. (...sorry)
|>
|>Anyway, in looking at the types of lathes, I've come up with the following
|>types. Anyone care to expound on the differences. For example, when I'm
|>looking to guy I always have to ask if it will cut threads. But a good
|>machinist would probably know which types cut threads and which ones
|>don't. Some of these terms appear to be marketing terms (precision). Are
|>there any that I missed? -johnbottoms (concord,ma)

As you mention, these are mostly marketing terms with no precise definition.
I'll attempt to supply the understanding of a rank amateur! :

|>Bench     size of the lathe is such that it will sit on a bench, ca. 8-10"
|>Camlock   the spindle is not threaded but has cams to hold chucks etc.
            this is faster in production shops and allows safe reverse running
|>Engine    several definitions.  more or less general purpose, I think
|>Gap bed   the bed has a removable gap under the headstock so you can mount
            large-diameter work if needed
|>Gear head    the head is gear-driven instead of belt-driven
|>Jewelers     very small
|>Precision    self-explanatory; usually small
|>Round bed    never heard this one; perhaps the carriage runs on round rods
               instead of sliding on v-ridges?
|>Spindle      the spindle is part of the lathe; never heard of a "spindle"
               lathe unless this is in contrast to a camlock
|>Swing gearhead    ??
|>Toolroom     sort of general purpose but "better"
|>Turret       the tailstock can hold multiple tools that can swing into place
|>Watchmakers  very small!

I'm sure others will have additions/corrections!

Jim

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From: [email-masked] (John W Bottoms)
Date: Tue, 22 Nov 1994 15:58:09 GMT

I wanta get lathe'd. (...sorry)

Anyway, in looking at the types of lathes, I've come up with the following
types. Anyone care to expound on the differences. For example, when I'm
looking to guy I always have to ask if it will cut threads. But a good
machinist would probably know which types cut threads and which ones
don't. Some of these terms appear to be marketing terms (precision). Are
there any that I missed? -johnbottoms (concord,ma)

Bench
Camlock
Engine
Gap bed
Gear head
Jewelers
Precision
Round bed
Spindle
Swing gearhead
Toolroom
Turret
Watchmakers

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From: [email-masked] (Mike Rehmus)
Date: 23 Nov 1994 00:51:46 GMT

Does anyone have information on the Rockford line of lathes?  I have an 
old (pre-WW2) 14" swing with a nine foot bed in very good shape.  No 
documentation although it is not too hard to figure out how to run the 
lathe.  I'd certainly pay for a reproduction of or an original manual 
if anybody has one.

I'm contemplating changing the lathe over from a threaded nose on the 
spindle to a D-type adaptor.  The adaptor doesn't look to be too hard to 
build.  Does anyone have specs on the adaptors or know where I can find 
them?

Thanks,

Mike Rehmus
[email-masked]

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From: [email-masked]
Date: 23 Nov 1994 05:02:14 GMT

In article <[email-masked]>, [email-masked] (Tim Kirby) writes:
>John W Bottoms ([email-masked]) wrote:
[...]

>
>Jewelers and Watchmakers generally refer to very small machines well suited
>to high precision work. I'd guess that a watchmakers would probably have
>screwcutting capabilities. Sizewise these are about the size of a sherline
>lathe - maybe 24" long overall.

24" is unusually long for a watchmaker's lathe; traditional ones (Boley,
Lorch, etc.) are usually more like 12" length. Screwcutting capability
is found on very few watchmaker's lathes. The traditional tools used
with these things are hand-held gravers. Anyway, this probably isn't
anything the original poster would be interested in...

>[...]
>
>Bench typically means it's a lathe suitable for standing on a bench, as far as
>I know. Probably relatively small - somewhere between 6 to 9 inch swing.
>Maybe an engine lathe is one that comes with a stand? :)
>[...]

I've certainly seen 12" bench lathes.

So what the heck does "engine lathe" mean, anyway? Does is mean it's
got a motor more-or-less built in instead of being designed to run
>from  an overhead shaft?

                      ...when I sit down to write
Don Holly             my intentions are always blameless however deplorable
                      the ultimate effect of the act may turn out to be.
                                           --Joseph Conrad

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From: [email-masked] (Bob Powell)
Date: 24 Nov 1994 01:40:09 GMT

>got a motor more-or-less built in instead of being designed to run

Still just a guess, but since nobody else has answered ...
>From  much contextual reading I've come to assume that the "engine" in
engine lathe just means that it has a gear and/or belt train to vary
the spindle speed.  The distinction was more relevant 100+ years ago
when the term was first applied.

---

From: [email-masked] (Joseph R. Landau)
Date: Thu, 24 Nov 1994 03:14:01 GMT

But what is a "second operation" lathe?

---

From: [email-masked] (Mark Fraser)
Date: 24 Nov 1994 04:38:25 GMT

Isn't an engine lathe one with a bunch of cams etc that makes a 
complex part repeatedly without an operator? [except to change
the workpiece]?  Mechanical predecessor of the CNC machine?
/Mark

Tim Kirby ([email-masked]) wrote:
: (I) Tim Kirby ([email-masked]) wrote:

: : Engine lathes, as far as I know, are "generic metalworking lathes". I have
: : yet to see someone come up with a *better* definition. It doesn't appear
: : to tell you much about the size, capacity or capabilities of the machine.

: I have since been reminded (Thanks Grant) that I have come across a better
: definition - I seem to recall we decided that an engine lathe was a lathe
: driven by an engine (sic). This might have been purely as opposed to a foot
: or water-wheel powered machine tool or may actually differentiate between
: a lathe fed by overhead driveshafts and belts vs. a lathe with it's own
: "engine". Whatever, it tends to be fairly generic these days.

: Tim
: --
: Tim Kirby _________ Cray Research Inc., Eagan, MN, USA __________ [email-masked]
: Software Division              System Support                +1-(612)-683-5390
: __________________________ Consider it disclaimed ____________________________
: If all else fails, Immortality may always be assured by spectacular error(JKG)

---

From: [email-masked] (Ron Ginger)
Date: Thu, 24 Nov 1994 14:17:47

In article <[email-masked]> [email-masked] (Joseph R. Landau) writes:
>From: [email-masked] (Joseph R. Landau)
>Date: Thu, 24 Nov 1994 03:14:01 GMT
>Subject: Re: Lathe Types

>But what is a "second operation" lathe?

A lathe made to do a second operation. :-)

In production shops this is likely a lathe with some special work holding 
chuck, often a collet , a special function tool post and no tailstock. No 
likely to have a geearbox or leadscrew either.  It is usually stripped down 
just to do special work. 

They are used to finish off a part which may have been partly turned and 
parted off. 

ron ginger

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From: [email-masked] (Ron Ginger)
Date: Thu, 24 Nov 1994 14:20:02

In article <[email-masked]> [email-masked] (Mark Fraser) writes:
>From: [email-masked] (Mark Fraser)
>Subject: Re: Lathe Types
>Date: 24 Nov 1994 04:38:25 GMT

>the workpiece]?  Mechanical predecessor of the CNC machine?

No. that would be an AUTOMATIC SCREW MACHINE.

I think ENGINE LATHE just means a BIG lathe, in contrast to a TOOLROOM lathe

ron ginger

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From: [email-masked] (Tim Kirby)
Date: 23 Nov 94 12:25:04 CST

(I) Tim Kirby ([email-masked]) wrote:

: Engine lathes, as far as I know, are "generic metalworking lathes". I have
: yet to see someone come up with a *better* definition. It doesn't appear
: to tell you much about the size, capacity or capabilities of the machine.

I have since been reminded (Thanks Grant) that I have come across a better
definition - I seem to recall we decided that an engine lathe was a lathe
driven by an engine (sic). This might have been purely as opposed to a foot
or water-wheel powered machine tool or may actually differentiate between
a lathe fed by overhead driveshafts and belts vs. a lathe with it's own
"engine". Whatever, it tends to be fairly generic these days.

Tim
--
Tim Kirby _________ Cray Research Inc., Eagan, MN, USA __________ [email-masked]
Software Division              System Support                +1-(612)-683-5390
__________________________ Consider it disclaimed ____________________________
If all else fails, Immortality may always be assured by spectacular error(JKG)

---

From: [email-masked] (Tim Kirby)
Date: 22 Nov 94 15:32:10 CST

John W Bottoms ([email-masked]) wrote:
: I wanta get lathe'd. (...sorry)

So you should be :)

: ...when I'm looking to guy I always have to ask if it will cut threads.
: But a good machinist would probably know which types cut threads and which
: ones don't...

: Bench, Camlock, Engine, Gap bed, Gear head, Jewelers, Precision
: Round bed, Spindle, Swing gearhead, Toolroom, Turret, Watchmakers

Well, a fairly obvious one is "screwcutting". That tells you if it will
cut threads or not. Seriously. *grin*.

You need to be careful about mixing apples and oranges here - between the
different types of lathes and features that you might find on those
machines. I'll take a swing at a few and let someone else refine it...

Engine lathes, as far as I know, are "generic metalworking lathes". I have
yet to see someone come up with a *better* definition. It doesn't appear
to tell you much about the size, capacity or capabilities of the machine.

Round bed refers to the shape of the bed - instead of inverted "V"s or
a dovetail arrangement the bed is effectively a tube. This is an old style
of machine - the only one that comes to mind to me is the ubiquitous
"Round Bed Drummond", not uncommon in the UK.

Gap Bed means that there is (potentially) a gap in the bed at the headstock
(I say potentially because some "gap bed lathes" come with an extra bit of
 bed that can be screwed in place to plug the hole). This allows items larger
than the swing-to-bed to be turned, often on a faceplate...

 (Poor ASCII representation follows)

                   -
                  | |
    ------------- | |
                |-| |
    Headstock   | | |
                |-| |           -----
                | | |           |
                | | |    -------| Saddle
                |  -     | Bed  |
                ----------      ------
                  Gap

A geared head merely means the headstock drive is all gears instead of belts
(well, the initial drive may be belt but speed selection is through a gearbox)

Turret lathes are typically machines made for mass production. I just tried
to come up with a simple explanation and couldn't off the top of my head.
Suffice it to say that, unless you are into making lots of the same thing
you probably won't want one.

Toolroom lathes are usually high precision machines intended for use by
toolmakers. Usually these are machines with collet type headstock arrangements
and again, these are not often particularly huge machines.

Uh, I gotta get back to work here :) I'll let someone else finish off/correct
as appropriate.

Tim

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From: [email-masked] (Jon Henry)
Date: 29 Nov 1994 05:38:43 GMT

In article <[email-masked]>, [email-masked] (John W

> there any that I missed? -johnbottoms (concord,ma)

Did anyone mention the spinning lathe, for shaping and forming thin sheets
of metal?

JH

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From: [email-masked] (Mike Rehmus)
Date: 2 Dec 1994 18:18:12 GMT

In <[email-masked]> 

>> there any that I missed? -johnbottoms (concord,ma)

I'm not an expert but I have investigated most of the confusing terms 
used to describe lathes.  I have also had a year of training at the 
local college on the use and operation of machine tools.  So I'm 
probably pretty dangerous, knowing just enough to get me in trouble.

The terms above are mixed up kind of like if you tried to describe car 
types by using the following terms in isolation:  4X4, automatic, ABS, 
radio, taxi, private car, sports car, etc.  Some of these terms define 
types and some define features.

One can divide lathes into several general categories according to their 
characteristics.  Those could be thought of as hobby, general shop use, 
toolroom, and specialty.

These lathes have one or more of the following specifications and 
features:

Size - 		swing, center to center distance, weight, bed dimensions
Drive - 	belt, gear, back-gear (a low speed option), direct
Accuracy - 	normal, toolroom (thought of as precise), specialty
Bearings - 	plain, ball, roller, air
Bed shapes - 	round, flat, v-way (and how many v-ways), special
Support - 	Table-top, Bench, free standing
Tool support - 	Carriage with cross slide and perhaps, compound slide, 	
		carriage with turret
Chuck attach. - Threaded spindle, short taper, long taper, cam-lock, 	
		etc.
Threading -	Change gears or quick-change
Power - 	110, 220, single or three phase.

These features can be combined (and are) in every way imaginable to meet 
the designer's objectives.  Then, someone in marketing puts a cute name 
on them and then prints the brochure.

At one time, all lathes were driven by human power, then by an overhead 
belt system powered by water, steam, or an IC engine.  When smaller 
electric motors became available, they powered each lathe individually 
and thereby invented the term "engine lathe".  YUP, thats all an engine 
lathe is . . . self powered as opposed to line powered.

Applications range from watchmaking to lathes that will turn the 
propeller shafts for large ships and everything inbetween.

Watchmaker's (jewelers) lathes are far different from what most of us 
want unless you are interested in watchmaking.  For general use in a 
hobby, most of us can get along quite happily with:

A 9-12 inch swing, 24"-30" between centers, engine lathe with a carriage 
that includes a compound slide, speed range that will let us turn mild 
steel with HSS tooling near the maximum swing and also let us turn small 
diameter brass or aluminum at the correct high speed.  If we are lucky, 
the lathe will have a collet adaptor and must have a three-jaw and 
four-jaw chuck of appropriate size. It will have a quick-change 
(swapping change gears is such a pain!) capable of cutting from 4 to 80 
TPI, and has a threading dial. (It would be nice if it would also cut 
metric but unlikely if the lathe is too old)  The handwheels on the 
slides and the tailstock will be calibrated in thousandths (maybe metric 
too). The lathe will come either on a very sturdy cabinet or we will 
build a steel (solid and heavy with adjustable feet for leveling) table 
and not use wood for the top.  The lathe will be powered by an electric 
motor for which we have the appropriate source in our shop.  If you need 
three phase for your lathe, it is unlikely you can get in in a private 
residence unless you live in the country.  A phase converter will work 
OK if three-phase is what you have to live with. (certain restrictions 
apply, talk to the converter manufacturer directly, I did and learned a 
lot.)  

You will also be lucky if you can purchase an American made lathe for 
which repair parts are still available.  Many lathes made outside the US 
are difficult to repair because parts are not available, even when they 
are new.  Obviously, reputable manufacturers in Europe and Japan will 
have repair parts although they are going to be expensive.

Just remember to determine the purpose for which you require the lathe 
and buy accordingly.  A 24 inch swing lathe is going to pretty hard to 
use if you want to make balance wheels for your grandfather's pocket 
watch.

Best regardsm and all of this is IMHO,

Mike Rehmus
[email-masked]