How is a lathe measured? I see one that is 7" x 10", then another more
expensive one that is 8" x 12". Where are such measurements taken and what
would be the differences?

Thank you.

"JWho" wrote in message
news:_sqcf.315606$084.262637@attbi_s22...
How is a lathe measured? I see one that is 7" x 10", then another more
expensive one that is 8" x 12". Where are such measurements taken and
what
would be the differences?

Thank you.

OK, further in the description, I see where it says:

Distance between centers: 10''
Swing over bed 7"

So, naturally, one questions causes more. Are lathes normally measured like
this?

What is a "swing over bad"??

Thank you.

JWho wrote:
How is a lathe measured? I see one that is 7" x 10", then another more
expensive one that is 8" x 12". Where are such measurements taken and what
would be the differences?

In the US, the first number is the maximum diameter workpiece that can
be rotated over the bed, in the UK it's apparently the radius. Note
that this dimension may shrink when you crank the carriage in close to
the work - there's a smaller number for swing over the cross slide.

The second number is the maximum length of workpiece that can be held
between centers, one on the headstock and one on the tailstock, like on
a wood lathe. If you install a chuck on the headstock this distance
will shrink some.

Another number often hidden in the specs but of great importance is the
size of the through hole in the headstock. This governs what size
barstock you can feed through, allowing only a little bit to hang out
of the chuck where you can work on it easily. While you can saw off
chunks for each part, that's very wastefull. For your bushings for
example, you'd probably want a lathe with at least 1" through hole. In
practice, smaller 9" swing bench top lathes are usually just over 3/4",
while larger 12-13" swing models can usually handle something like 1
3/8". Some of the little tabletop lathes like the sherline have a
through hole less than 1/2", a major annoyance since 1/2" stock is so
usefull.

"JWho" wrote in message
news:_sqcf.315606$084.262637@attbi_s22...
How is a lathe measured? I see one that is 7" x 10", then another more
expensive one that is 8" x 12". Where are such measurements taken and
what
would be the differences?

Thank you.


Cubits!

Go here for more info on mini lathes and mills. Good info for
beginners.
http://www.mini-lathe.com/
-Mike

wrote in message
ups.com...
JWho wrote:
How is a lathe measured? I see one that is 7" x 10", then another more
expensive one that is 8" x 12". Where are such measurements taken and
what
would be the differences?

In the US, the first number is the maximum diameter workpiece that can
be rotated over the bed, in the UK it's apparently the radius. Note
that this dimension may shrink when you crank the carriage in close to
the work - there's a smaller number for swing over the cross slide.

Hi. Thank you for the reply. I understand what you mean on the diameter of
the workpiece. I am in AL, USA, by the way.


The second number is the maximum length of workpiece that can be held
between centers, one on the headstock and one on the tailstock, like on
a wood lathe. If you install a chuck on the headstock this distance
will shrink some.

When you say chuck, is that similar to a chuck on a cordless/electrical
drill, just special for a lathe? It's for holding a tube or rod or similar,
correct?



Another number often hidden in the specs but of great importance is the
size of the through hole in the headstock. This governs what size
barstock you can feed through, allowing only a little bit to hang out
of the chuck where you can work on it easily. While you can saw off
chunks for each part, that's very wastefull. For your bushings for
example, you'd probably want a lathe with at least 1" through hole. In
practice, smaller 9" swing bench top lathes are usually just over 3/4",
while larger 12-13" swing models can usually handle something like 1
3/8". Some of the little tabletop lathes like the sherline have a
through hole less than 1/2", a major annoyance since 1/2" stock is so
usefull.

Here is the one I am referring to.

http://www.harborfreight.com/cpi/cta...emnumber=33684

At the bottom, it has, "Through chuck capacity: 5/8" ". Is that the same as
"through hole in the headstock" that you mentioned? Would that make it
unable to use some size of solid rod, or would it just make it less
convenient or use more rod?? I am not 100% sure what that means to me.

Thanks! This newsgroup is great!

"mlcorson" wrote in message
oups.com...
Go here for more info on mini lathes and mills. Good info for
beginners.
http://www.mini-lathe.com/
-Mike


I'm there! Thanks!!

JWho wrote:
Here is the one I am referring to.

http://www.harborfreight.com/cpi/cta...emnumber=33684

At the bottom, it has, "Through chuck capacity: 5/8" ". Is that the same as
"through hole in the headstock" that you mentioned? Would that make it
unable to use some size of solid rod, or would it just make it less
convenient or use more rod?? I am not 100% sure what that means to me.

That's advertised in their retail store for $369.99.
They emailed me a 20% Off coupon.
That makes it $296
That is very tempting.

Rex

JWho wrote:

When you say chuck, is that similar to a chuck on a cordless/electrical
drill, just special for a lathe? It's for holding a tube or rod or similar,
correct?

Well, sorta in that it used multiple jaws to hold things, but it's much
larger and heavier and designed to take side loads that a jacobs chuck
(drill chuck) couldn't.

At the bottom, it has, "Through chuck capacity: 5/8" ". Is that the same as
"through hole in the headstock" that you mentioned? Would that make it
unable to use some size of solid rod, or would it just make it less
convenient or use more rod?? I am not 100% sure what that means to me.

Yes, same dimension. What it would mean is that if you wanted to make
something like your bushing out of stock thicker than 5/8", you would
need to saw off a pice that you could hold in the chuck. You'd do all
your turning, then probably use a parting tool to turn the section you
want off of a wasted stub left in the chuck. Wheras if you had a
larger through capacity, you could just work on the end of a longer
piece and only part off what you need when you are done.

wrote in message
ups.com...
JWho wrote:

When you say chuck, is that similar to a chuck on a cordless/electrical
drill, just special for a lathe? It's for holding a tube or rod or
similar,
correct?

At the bottom, it has, "Through chuck capacity: 5/8" ". Is that the same
as
"through hole in the headstock" that you mentioned? Would that make it
unable to use some size of solid rod, or would it just make it less
convenient or use more rod?? I am not 100% sure what that means to me.


As another example, suppose you wanted to machine some fittings at both ends
of a long shaft. Say 15 feet long or so and that you just wanted to turn 2"
at the ends down to 1/2" say. If the through hole in the headstock is 1/2",
then the largest diameter shaft you could turn would 1/2". If the headstock
hole was 3", the maximum shaft diameter would be about 3" .. in both cases,
the length is limited by the room you have in your shop to the left of the
lathe because only a little bit has to stick out into the working part of
the lathe -- the 2" length you wanted to machine. Now suppose that you
headstock hole is 1" and you want to turn the ends of a 10 foot shaft, 1.5"
in diameter. Can't be done on that lathe .. at least not with reasonable
convenience. You would be limited to a length slightly less than "the
distance between centers."
The hole through the headstock is generally much less than the hole
through a chuck. That's a property of the chuck, not the lathe. Of course,
if you have a 3" hole in the chuck and a 1" hole in the headstock, you can't
push your work further in than the point at which the work touches the
spindle.... at least not twice on the same lathe.
The size of the hole through the headstock is far more important in
a production setting where the material is being fed through the headstock
to the cutting tools. Since most home shop machinists rarely turn long,
large diameter, shaftings, the issue is mostly a matter of convenience and
wasted material, as pointed out earlier... until, of course, that day when
you absolutely must have that larger diameter.
That's the first order approximation. Now for some refinements of
the idea. You should always keep the working part (the place you are
cutting metal) as close to the headstock as you can. That cuts down on
chatter (you'll learn about that soon enough), and makes it easier to hold
accuracy all along the piece. A long piece much be held at one end by the
chuck and at the other by the tailstock point. The longer that distance,
the wobblier the work becomes .. with many attendant problems. For that
reason, working long pieces not partly in the headstock means you'll have to
use a steady rest or a follower rest or both.
The third order approximation... For very accurate work you do all
the machining between centers, with nothing stuch through the headstock
hole.

Get hold of the lovely little book "How to Run a Lathe", originally
published by South Bend, but now available very reasonably from Lindsay
publication.


--

-------------------------------------
Boris Beizer Ph.D. Seminars and Consulting
1232 Glenbrook Road on Software Testing and
Huntingdon Valley, PA 19006 Quality Assurance

TEL: 215-572-5580
FAX: 215-886-0144
Email bsquare "at" earthlink.net

------------------------------------------

"Boris Beizer" wrote in message
nk.net...

wrote in message
ups.com...
JWho wrote:

When you say chuck, is that similar to a chuck on a cordless/electrical
drill, just special for a lathe? It's for holding a tube or rod or
similar,
correct?

At the bottom, it has, "Through chuck capacity: 5/8" ". Is that the
same
as
"through hole in the headstock" that you mentioned? Would that make it
unable to use some size of solid rod, or would it just make it less
convenient or use more rod?? I am not 100% sure what that means to me.


As another example, suppose you wanted to machine some fittings at both
ends
of a long shaft. Say 15 feet long or so and that you just wanted to turn
2"
at the ends down to 1/2" say. If the through hole in the headstock is
1/2",
then the largest diameter shaft you could turn would 1/2". If the
headstock
hole was 3", the maximum shaft diameter would be about 3" .. in both
cases,
the length is limited by the room you have in your shop to the left of the
lathe because only a little bit has to stick out into the working part of
the lathe -- the 2" length you wanted to machine. Now suppose that you
headstock hole is 1" and you want to turn the ends of a 10 foot shaft,
1.5"
in diameter. Can't be done on that lathe .. at least not with reasonable
convenience. You would be limited to a length slightly less than "the
distance between centers."
The hole through the headstock is generally much less than the
hole
through a chuck. That's a property of the chuck, not the lathe. Of
course,
if you have a 3" hole in the chuck and a 1" hole in the headstock, you
can't
push your work further in than the point at which the work touches the
spindle.... at least not twice on the same lathe.
The size of the hole through the headstock is far more important
in
a production setting where the material is being fed through the headstock
to the cutting tools. Since most home shop machinists rarely turn long,
large diameter, shaftings, the issue is mostly a matter of convenience and
wasted material, as pointed out earlier... until, of course, that day when
you absolutely must have that larger diameter.
That's the first order approximation. Now for some refinements of
the idea. You should always keep the working part (the place you are
cutting metal) as close to the headstock as you can. That cuts down on
chatter (you'll learn about that soon enough), and makes it easier to hold
accuracy all along the piece. A long piece much be held at one end by the
chuck and at the other by the tailstock point. The longer that distance,
the wobblier the work becomes .. with many attendant problems. For that
reason, working long pieces not partly in the headstock means you'll have
to
use a steady rest or a follower rest or both.
The third order approximation... For very accurate work you do
all
the machining between centers, with nothing stuch through the headstock
hole.

Get hold of the lovely little book "How to Run a Lathe",
originally
published by South Bend, but now available very reasonably from Lindsay
publication.


--

-------------------------------------
Boris Beizer Ph.D. Seminars and Consulting
1232 Glenbrook Road on Software Testing and
Huntingdon Valley, PA 19006 Quality Assurance

TEL: 215-572-5580
FAX: 215-886-0144
Email bsquare "at" earthlink.net

------------------------------------------

HUM! I think I see what is meant now! One can work on a rod longer than
10" as long as it is 5/8" thick or less, correct? Assuming that is correct,
then your points on it being more and more wobbly as the rod got longer
makes perfect sense. Right now, I can only think of two parts I would ever
make, and neither is longer than 10". Before this, I thought every rod had
to be inside the two centers.

THANKS, gentlemen!

JWho wrote:

HUM! I think I see what is meant now! One can work on a rod longer than
10" as long as it is 5/8" thick or less, correct? Assuming that is correct,
then your points on it being more and more wobbly as the rod got longer
makes perfect sense. Right now, I can only think of two parts I would ever
make, and neither is longer than 10". Before this, I thought every rod had
to be inside the two centers.

Actually you can't work a thin rod anywhere near the capacity length of
the lathe, because it will flex and chatter, rubbing against the tool
rather than cutting smoothly. You can probably only turn something a
few diameters long that is hanging out of the chuck, a bit longer if it
is also supported at the tailstock end. With something really long and
thin, you could work an area near the headstock, and a shorter area
real near the tailstock center, but not in between. And you'd have
trouble drilling the hole for the tailstock center, since you couldn't
support the work near where you'd be drilling.

I'm going to guess that for half inch stock, the practical limit for
chuck support is less than 3" maybe 4.5 or 5" if you support the other
end with the tailstock. Could be wrong though, lathe has been in
storage fora few years.

Incidentally, long piece hanging unsupported out of either end of a
lathe's headstock can be quite dangerous - either the end you are
working on, or spare stock hanging out the other side. They invariably
flex, and the more they flex the more the rotation makes them flex even
more - with the result that they can end up flailing around whacking
expensive stuff like you, crashing into the bed, or in an extreme case
even knocking the machine over.

wrote in message
oups.com...
JWho wrote:

HUM! I think I see what is meant now! One can work on a rod longer
than
10" as long as it is 5/8" thick or less, correct? Assuming that is
correct,
then your points on it being more and more wobbly as the rod got longer
makes perfect sense. Right now, I can only think of two parts I would
ever
make, and neither is longer than 10". Before this, I thought every rod
had
to be inside the two centers.

Actually you can't work a thin rod anywhere near the capacity length of
the lathe, because it will flex and chatter, rubbing against the tool
rather than cutting smoothly. You can probably only turn something a
few diameters long that is hanging out of the chuck, a bit longer if it
is also supported at the tailstock end. With something really long and
thin, you could work an area near the headstock, and a shorter area
real near the tailstock center, but not in between. And you'd have
trouble drilling the hole for the tailstock center, since you couldn't
support the work near where you'd be drilling.

I'm going to guess that for half inch stock, the practical limit for
chuck support is less than 3" maybe 4.5 or 5" if you support the other
end with the tailstock. Could be wrong though, lathe has been in
storage fora few years.

Incidentally, long piece hanging unsupported out of either end of a
lathe's headstock can be quite dangerous - either the end you are
working on, or spare stock hanging out the other side. They invariably
flex, and the more they flex the more the rotation makes them flex even
more - with the result that they can end up flailing around whacking
expensive stuff like you, crashing into the bed, or in an extreme case
even knocking the machine over.


All that you mentioned is just for a rod that is over 10" though, correct?
I think the thing I would want to make is about 8" or 9". I can envision
what you mean on it wobbling. It would be like a fiberglass rod. Pretty
soon it is like a lasso. :-| Sounds dangerous!

Thanks.

"JWho" wrote in message
news:rutcf.556945$xm3.194111@attbi_s21...

wrote in message
oups.com...
JWho wrote:

HUM! I think I see what is meant now! One can work on a rod longer
than
10" as long as it is 5/8" thick or less, correct? Assuming that is
correct,
then your points on it being more and more wobbly as the rod got longer
makes perfect sense. Right now, I can only think of two parts I would
ever
make, and neither is longer than 10". Before this, I thought every rod
had
to be inside the two centers.

Actually you can't work a thin rod anywhere near the capacity length of
the lathe, because it will flex and chatter, rubbing against the tool
rather than cutting smoothly. You can probably only turn something a
few diameters long that is hanging out of the chuck, a bit longer if it
is also supported at the tailstock end. With something really long and
thin, you could work an area near the headstock, and a shorter area
real near the tailstock center, but not in between. And you'd have
trouble drilling the hole for the tailstock center, since you couldn't
support the work near where you'd be drilling.

I'm going to guess that for half inch stock, the practical limit for
chuck support is less than 3" maybe 4.5 or 5" if you support the other
end with the tailstock. Could be wrong though, lathe has been in
storage fora few years.

All that you mentioned is just for a rod that is over 10" though, correct?
I think the thing I would want to make is about 8" or 9". I can envision
what you mean on it wobbling. It would be like a fiberglass rod. Pretty
soon it is like a lasso. :-| Sounds dangerous!

The rule of thumb is never to go more than three diameters unsupported ..
and that is pushing it. If the job is done between centers, or between a
chuck and a tailstock center, then it is supported on both ends and you can
go 4 to 6 diameters without intermediate support. You can go longer and
thinner than this in two (actually, three) ways.

1. Very carefully, with very careful adjustment of the tool height, light
cuts, and very, very, sharp, properly sharpened, tool bits.

2. Use a steady rest. This is an intermediate support that stays fixed on
the lathe bed. Gives you an additional support point. A bit of a PITA if
you're machining the whole length because you have to move the steady rest
if it is on the spot you want to machine. Has to be reset for each pass.

3. A movable steady rest.. called a "follower rest." This attaches to the
carriage and moves along with it... typically behind the cutting tool. Has
to be reset for each pass.

A word of caution on long things in small lathes that fit through
the headstock. If the stock sticks out of the headstock's left end more
than ten or twenty diameters, it will wobble, and eventually bend. This
happens quite catastrophically since the more it bends, the greater the
centrifugal force that makes it bend even more. The least it will do is
bend your stock to uselessness. Somewhat worse is deep gouges in your
workbench, or even worse, removal of sundry body parts that are in the
region.

Boris

--

-------------------------------------
Boris Beizer Ph.D. Seminars and Consulting
1232 Glenbrook Road on Software Testing and
Huntingdon Valley, PA 19006 Quality Assurance

TEL: 215-572-5580
FAX: 215-886-0144
Email bsquare "at" earthlink.net

------------------------------------------

"Boris Beizer" wrote in message
nk.net...

"JWho" wrote in message
news:rutcf.556945$xm3.194111@attbi_s21...

wrote in message
oups.com...
JWho wrote:

HUM! I think I see what is meant now! One can work on a rod longer
than
10" as long as it is 5/8" thick or less, correct? Assuming that is
correct,
then your points on it being more and more wobbly as the rod got
longer
makes perfect sense. Right now, I can only think of two parts I
would
ever
make, and neither is longer than 10". Before this, I thought every
rod
had
to be inside the two centers.

Actually you can't work a thin rod anywhere near the capacity length of
the lathe, because it will flex and chatter, rubbing against the tool
rather than cutting smoothly. You can probably only turn something a
few diameters long that is hanging out of the chuck, a bit longer if it
is also supported at the tailstock end. With something really long and
thin, you could work an area near the headstock, and a shorter area
real near the tailstock center, but not in between. And you'd have
trouble drilling the hole for the tailstock center, since you couldn't
support the work near where you'd be drilling.

I'm going to guess that for half inch stock, the practical limit for
chuck support is less than 3" maybe 4.5 or 5" if you support the other
end with the tailstock. Could be wrong though, lathe has been in
storage fora few years.

All that you mentioned is just for a rod that is over 10" though,
correct?
I think the thing I would want to make is about 8" or 9". I can
envision
what you mean on it wobbling. It would be like a fiberglass rod.
Pretty
soon it is like a lasso. :-| Sounds dangerous!

The rule of thumb is never to go more than three diameters unsupported ..
and that is pushing it. If the job is done between centers, or between a
chuck and a tailstock center, then it is supported on both ends and you
can
go 4 to 6 diameters without intermediate support. You can go longer and
thinner than this in two (actually, three) ways.

1. Very carefully, with very careful adjustment of the tool height, light
cuts, and very, very, sharp, properly sharpened, tool bits.

2. Use a steady rest. This is an intermediate support that stays fixed
on
the lathe bed. Gives you an additional support point. A bit of a PITA if
you're machining the whole length because you have to move the steady rest
if it is on the spot you want to machine. Has to be reset for each pass.

3. A movable steady rest.. called a "follower rest." This attaches to
the
carriage and moves along with it... typically behind the cutting tool.
Has
to be reset for each pass.

A word of caution on long things in small lathes that fit through
the headstock. If the stock sticks out of the headstock's left end more
than ten or twenty diameters, it will wobble, and eventually bend. This
happens quite catastrophically since the more it bends, the greater the
centrifugal force that makes it bend even more. The least it will do is
bend your stock to uselessness. Somewhat worse is deep gouges in your
workbench, or even worse, removal of sundry body parts that are in the
region.

Boris

Thank you for the additional information. I saw one of those steady rests
on the HF site.

I had mentioned making a part besides some bushings. It turns out the final
product is 10.5" and over 5/8" wide. So basically, I can not make it on the
HF $350 7" x 10" lathe, correct?

Thanks.

wrote in message
ups.com...
JWho wrote:
How is a lathe measured? I see one that is 7" x 10", then another more
expensive one that is 8" x 12". Where are such measurements taken and
what
would be the differences?

In the US, the first number is the maximum diameter workpiece that can
be rotated over the bed, in the UK it's apparently the radius. Note
that this dimension may shrink when you crank the carriage in close to
the work - there's a smaller number for swing over the cross slide.

The second number is the maximum length of workpiece that can be held
between centers, one on the headstock and one on the tailstock, like on
a wood lathe. If you install a chuck on the headstock this distance
will shrink some.


Correct----most of the time. The tag on my old South Bend reads size "14
1/2 x 72"
The 14 1/2 is the swing diameter over the ways. The 72 is the total length
of the bed!
I've never measured center-to-center, but suspect it is around 32.

Bill

The accepted form is-
Swing over bed- maximum diameter of piece that can clear the main bedway
Swing over carriage- maximum diameter that can clear the carriage
Distance between centers- maximum distance form spindle nose to tailstock
barrel ( The actual working distance is usually slightly less due to the
length of centers and can vary depending on the style and manufacture of
tools being used. So if you have a 12X36 lathe, the working distance will
be more like 30-32" ) Some manufacturers will rate this based on their own
proprietary tooling and then it is measured from center tip to tip.
"JWho" wrote in message
news:_sqcf.315606$084.262637@attbi_s22...
How is a lathe measured? I see one that is 7" x 10", then another more
expensive one that is 8" x 12". Where are such measurements taken and
what
would be the differences?

Thank you.

"EdFielder" wrote in message
nk.net...
The accepted form is-
Swing over bed- maximum diameter of piece that can clear the main bedway
Swing over carriage- maximum diameter that can clear the carriage
Distance between centers- maximum distance form spindle nose to tailstock
barrel ( The actual working distance is usually slightly less due to the
length of centers and can vary depending on the style and manufacture of
tools being used. So if you have a 12X36 lathe, the working distance will
be more like 30-32" ) Some manufacturers will rate this based on their
own
proprietary tooling and then it is measured from center tip to tip.
"JWho" wrote in message
news:_sqcf.315606$084.262637@attbi_s22...
How is a lathe measured? I see one that is 7" x 10", then another more
expensive one that is 8" x 12". Where are such measurements taken and
what
would be the differences?

Thank you.

Thanks for the information. That "actual working distance" was the kicker
on the Harbor Feight 7" x 10" lathe. :-(

In article . com,
says...

The second number is the maximum length of workpiece that can be held
between centers, one on the headstock and one on the tailstock, like on
a wood lathe.

This is actually incorrect, at least in the US.

"Swing" is max diameter able to turned over the ways.

"Bed length" is defined as the *total* length of the bed.

In the UK it's swing radius X bed length between centers.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

You've got to be careful. The first number is the diameter that can be
turned over the ways (though sometimes it's the radius, but that's
usually pretty obvious). The second number is EITHER the total length of
the ways, OR the maximum distance between centers. It's totally
inconsistent. I've seen my Craftsman lathe sold on eBay as a 12" x 32"
(length between centers) 12" x 36" (length between headstock and end of
ways) or a 12" x 48" (length of bed). You have to be careful. I nearly
bit on a South Bend ~10" x 24" one time until I looked closely at the
pictures and realized the 24" was the length of the ways. Maximum length
between centers, ~8" I'd guess.

Jim