"Joseph Gwinn" wrote in message
...
In article ,
"Ed Huntress" wrote:

"Jim Wilkins" wrote in message
...
On Nov 24, 1:04 pm, "Ed Huntress" wrote:
"Jim Wilkins" wrote in message
...
I just checked my two best sources, Holtzapffel #2 and Oscar Perrigo's
1916 "Lathe Design", ...
...
As I think about this, I'm remembering what I thought about it at the
time,
30 years ago. I believed then that the issue was the difficulty,
without
planers, mills, or big surface grinders, of getting the four planes of
a
pair of V-ways coordinated for straight and smooth travel. One way to
interpret this is that you can adjust the single plane of the flat way
a
lot
easier than the pair of planes you have with a second V. So to say that
it
was simpler to correct accuracy with the V-and-flat could just mean
that;
if
the ways are hand-finished, you're correcting accuracy, and V-and-flat
is
a
lot easier to correct than two V's.

Maybe. g

--
Ed Huntress

If I read Holtzapffel correctly the two sides of inverted vee ways
were at first made separately, joined and aligned afterwards to fit
the fixed and moving poppit heads (headstock and tailstock to us).

Yeah. In the very beginning of modern lathes, the V-and-flat combinations
were assembled the same way. The first screw-cutting lathes had wood beds
with bolted-on iron ways, IIRC. (I'm doing this from memory; don't bite
me.
g)

"This slight width of base does not afford sufficient lateral support
to the heads, which with only moderate force in turning are liable to
vibration; while exact parallelism of the two angular edged bars is
also necessary. Improvement in stability was sought by making one side
of the bearers flat and broad, fig. 72, with a corresponding flat on
the underside of the lathe heads; retaining one angular side, to give
the direction or common axis. This arrangement also facilitated the
construction, as the parallelism of the two bars was no longer
essential,..."

Right. That sounds familiar.


Fig 72 shows one flat and one inverted vee way on a cast iron bed.

The difficulties of the early machine builders that Holtzapffel
recorded aren't that much different from those of a homebrew machine
tool maker today, except that we can buy ground drill rod and flat
stock and they could hire cheap child labor for tedious hand fitting.

Right. Maybe you've peeked at my ideas for a ferrocement lathe with steel
ways. d8-)

(Having finished reading Naaman's _Ferrocement & Laminated Cementitious
Composites_, I'm less enthusiastic about that construction.)

Significant work has been done on concrete-filled fabricated metal
frames for precision machine tools.

The place to start is MIT professor Alexander H. Slocum
(http://meche.mit.edu:16080/people/index.html?id=80). A good discussion
and many references may be found in his book "Precision Machine Design".

Joe Gwinn

Thanks, Joe. I talked to Slocum not too long ago -- maybe a year or two --
and someone here brought up his book before (maybe you?) -- it's on my list
of things to get for my library. I had a copy for a couple of weeks on an
interlibrary loan, and I read what he had to say about long-term stability
and so on, which helped a lot.

I should point out that I was studying and writing about concrete- and
polymer/aggregate-base machines around 30 years ago, and I've visited
manufacturers of them in the US and in France and Italy, mostly around that
time but as recently as seven years ago. I'm familiar in general with the
various approaches, the materials, and the design philosophies. But I've
never claimed expertise; it was more on the level of a good journalistic
exercise.

The commercial applications are one thing. This wild hair I've been chasing
has more to do with exploring strategies for building at home, at very low
cost, and to see what can be done with a material that's intrigued me for 40
years -- ferrocement. The obvious approach to building a machine like this
would be either a fairly massive, fiber-filled casting or a screw-tensioned,
post-tensioned cast structure. The former is my next area of study and it's
a big one. The latter is something I've abandoned because of problems with
long-term stability and engineering that's trickier than it looks. But it
would be a great way to go, if it wasn't for the stability issue.

I'm convinced that a concrete machine can deliver ordinary lathe accuracy
and could be perfectly suitable for the hobbyist. Problems crop up when you
go for high-end, toolroom-grade accuracy and long-term stability. The
polymers are better for that but they're *very* expensive, and defeat the
basic goals I'm starting with.

Anyway, thanks for the tip. I would love to go for this in a big way, but it
isn't in the cards right now. I'm engaged in conversation with Dr. Senft on
Stirling engine lubrication, and the outcome is going to eat me up for
months to come. d8-)

BTW, if anyone is interested in the approach you mention, which is various
forms of making a light welded or bolted steel structure and filling it with
concrete, it has possibilities for the home builder. But it's a lot trickier
than you might think. There are bonding issues and problems with the
different coefficients of expansion between steel and various...er,
"fillings," plus retained-stress issues with the steel itself. And concrete
grows (or shrinks; I forget) for decades after it's cast. It's not enough to
matter in building structures but it can be an issue when you're dealing
with thousandths of an inch.

--
Ed Huntress

"Gunner Asch" wrote in message
...
On Wed, 25 Nov 2009 00:47:42 -0500, Ned Simmons
wrote:


Hmm. Is that right? I thought Hardinges had the classic
two-bearing-front,
floating rear setup. But I don't know for sure. Maybe Gunner would know.

It's as I've described. I've been in there and have a picture here in
front of me.


Very early Hardinges had the 2 bearing front..1940s-early 50s
vintage..but since the late 50s..all have been as Ned said.

Thats for manual and microswitch automatics.

Gunner

Thanks, Gunner. It's not that I don't believe Ned, it's just that I *know*
I've seen that two-bearing arrangement on drawings of Hardinge spindles. I
guess it was just the old ones.

Now Ned has me going. g I'm not going to be happy until I figure out what
they're doing with a spindle that contains preloaded bearings at each end.
Something is unusual here. I just called Hardinge; all of my old contacts
are either dead or retired. d8-( (Hardinge was once my client.) The
service desk doesn't even know of anyone on their staff who would know about
them anymore.

sigh Another question that will have to go to the end of a long line...

--
Ed Huntress

On Nov 25, 10:58*am, "Ed Huntress" wrote:
...And concrete
grows (or shrinks; I forget) for decades after it's cast. It's not enough to
matter in building structures but it can be an issue when you're dealing
with thousandths of an inch.
Ed Huntress

I wonder if you could get around that by decoupling the ways from the
frame, perhaps mount them between clamping cap screws and supporting
setscrews and realign them to a straightedge before a critical job. It
would be like spotting and scraping, but quicker.

I've built a few instruments using that principle and found I could
hit micron accuracy as long as the screw seating surfaces were smooth
and lubricated and I left room for a wrench on both the pushing and
pulling screws at the same time, so I could slowly increase the torque
on both as the position readout approached zero.

My proof-of-concept demo to get permission was adjusting a 4-jaw lathe
chuck to within a micron. They brought me in as the electronic tech
and I had to prove that I could do the mechanical design and
construction of the lab prototypes as well.

jsw

In article ,
"Ed Huntress" wrote:

"Joseph Gwinn" wrote in message
...
In article ,
"Ed Huntress" wrote:

"Jim Wilkins" wrote in message
...
On Nov 24, 1:04 pm, "Ed Huntress" wrote:
"Jim Wilkins" wrote in message
...
I just checked my two best sources, Holtzapffel #2 and Oscar Perrigo's
1916 "Lathe Design", ...
...
As I think about this, I'm remembering what I thought about it at the
time,
30 years ago. I believed then that the issue was the difficulty,
without
planers, mills, or big surface grinders, of getting the four planes of
a
pair of V-ways coordinated for straight and smooth travel. One way to
interpret this is that you can adjust the single plane of the flat way
a
lot
easier than the pair of planes you have with a second V. So to say that
it
was simpler to correct accuracy with the V-and-flat could just mean
that;
if
the ways are hand-finished, you're correcting accuracy, and V-and-flat
is
a
lot easier to correct than two V's.

Maybe. g

--
Ed Huntress

If I read Holtzapffel correctly the two sides of inverted vee ways
were at first made separately, joined and aligned afterwards to fit
the fixed and moving poppit heads (headstock and tailstock to us).

Yeah. In the very beginning of modern lathes, the V-and-flat combinations
were assembled the same way. The first screw-cutting lathes had wood beds
with bolted-on iron ways, IIRC. (I'm doing this from memory; don't bite
me.
g)

"This slight width of base does not afford sufficient lateral support
to the heads, which with only moderate force in turning are liable to
vibration; while exact parallelism of the two angular edged bars is
also necessary. Improvement in stability was sought by making one side
of the bearers flat and broad, fig. 72, with a corresponding flat on
the underside of the lathe heads; retaining one angular side, to give
the direction or common axis. This arrangement also facilitated the
construction, as the parallelism of the two bars was no longer
essential,..."

Right. That sounds familiar.


Fig 72 shows one flat and one inverted vee way on a cast iron bed.

The difficulties of the early machine builders that Holtzapffel
recorded aren't that much different from those of a homebrew machine
tool maker today, except that we can buy ground drill rod and flat
stock and they could hire cheap child labor for tedious hand fitting.

Right. Maybe you've peeked at my ideas for a ferrocement lathe with steel
ways. d8-)

(Having finished reading Naaman's _Ferrocement & Laminated Cementitious
Composites_, I'm less enthusiastic about that construction.)

Significant work has been done on concrete-filled fabricated metal
frames for precision machine tools.

The place to start is MIT professor Alexander H. Slocum
(http://meche.mit.edu:16080/people/index.html?id=80). A good discussion
and many references may be found in his book "Precision Machine Design".

Joe Gwinn

Thanks, Joe. I talked to Slocum not too long ago -- maybe a year or two --
and someone here brought up his book before (maybe you?)

Very likely. I recall posting the reference before. Yes. The thread
was "Epoxy grainite build yer own machine frame" in March 2009.


-- it's on my list
of things to get for my library. I had a copy for a couple of weeks on an
interlibrary loan, and I read what he had to say about long-term stability
and so on, which helped a lot.

I bet you can borrow it again.


I should point out that I was studying and writing about concrete- and
polymer/aggregate-base machines around 30 years ago, and I've visited
manufacturers of them in the US and in France and Italy, mostly around that
time but as recently as seven years ago. I'm familiar in general with the
various approaches, the materials, and the design philosophies. But I've
never claimed expertise; it was more on the level of a good journalistic
exercise.

The commercial applications are one thing. This wild hair I've been chasing
has more to do with exploring strategies for building at home, at very low
cost, and to see what can be done with a material that's intrigued me for 40
years -- ferrocement. The obvious approach to building a machine like this
would be either a fairly massive, fiber-filled casting or a screw-tensioned,
post-tensioned cast structure. The former is my next area of study and it's
a big one. The latter is something I've abandoned because of problems with
long-term stability and engineering that's trickier than it looks. But it
would be a great way to go, if it wasn't for the stability issue.

Slocum runs hot and cold about concrete versus lots of cast iron, but he
isn't trying for infinite life either.

If it's cheap enough, people will live with something that doesn't last
100 years. Most HSMers won't last that long.


I'm convinced that a concrete machine can deliver ordinary lathe accuracy
and could be perfectly suitable for the hobbyist. Problems crop up when you
go for high-end, toolroom-grade accuracy and long-term stability. The
polymers are better for that but they're *very* expensive, and defeat the
basic goals I'm starting with.

Anyway, thanks for the tip. I would love to go for this in a big way, but it
isn't in the cards right now. I'm engaged in conversation with Dr. Senft on
Stirling engine lubrication, and the outcome is going to eat me up for
months to come. d8-)

Is there a good solution? I recall that this was one of the big issues.


BTW, if anyone is interested in the approach you mention, which is various
forms of making a light welded or bolted steel structure and filling it with
concrete, it has possibilities for the home builder. But it's a lot trickier
than you might think. There are bonding issues and problems with the
different coefficients of expansion between steel and various...er,
"fillings," plus retained-stress issues with the steel itself. And concrete
grows (or shrinks; I forget) for decades after it's cast. It's not enough to
matter in building structures but it can be an issue when you're dealing
with thousandths of an inch.

Yes. Slocum goes over this.

The issue is to replicate the static and dynamic stiffness of cast iron
more cheaply (or with less weight) than cast iron.

A fabricated box-beam frame has plenty of static stiffness, but has far
too little damping, so the dynamic stiffness is scant. Filling the
frame is an attempt to sharply increase the damping and thus dynamic
stiffness, to make the chatter threshold more remote.

Joe Gwinn

"Joseph Gwinn" wrote in message
...
In article ,
"Ed Huntress" wrote:

"Joseph Gwinn" wrote in message
...
In article ,
"Ed Huntress" wrote:

"Jim Wilkins" wrote in message
...
On Nov 24, 1:04 pm, "Ed Huntress" wrote:
"Jim Wilkins" wrote in message
...
I just checked my two best sources, Holtzapffel #2 and Oscar
Perrigo's
1916 "Lathe Design", ...
...
As I think about this, I'm remembering what I thought about it at
the
time,
30 years ago. I believed then that the issue was the difficulty,
without
planers, mills, or big surface grinders, of getting the four planes
of
a
pair of V-ways coordinated for straight and smooth travel. One way
to
interpret this is that you can adjust the single plane of the flat
way
a
lot
easier than the pair of planes you have with a second V. So to say
that
it
was simpler to correct accuracy with the V-and-flat could just mean
that;
if
the ways are hand-finished, you're correcting accuracy, and
V-and-flat
is
a
lot easier to correct than two V's.

Maybe. g

--
Ed Huntress

If I read Holtzapffel correctly the two sides of inverted vee ways
were at first made separately, joined and aligned afterwards to fit
the fixed and moving poppit heads (headstock and tailstock to us).

Yeah. In the very beginning of modern lathes, the V-and-flat
combinations
were assembled the same way. The first screw-cutting lathes had wood
beds
with bolted-on iron ways, IIRC. (I'm doing this from memory; don't
bite
me.
g)

"This slight width of base does not afford sufficient lateral support
to the heads, which with only moderate force in turning are liable to
vibration; while exact parallelism of the two angular edged bars is
also necessary. Improvement in stability was sought by making one
side
of the bearers flat and broad, fig. 72, with a corresponding flat on
the underside of the lathe heads; retaining one angular side, to give
the direction or common axis. This arrangement also facilitated the
construction, as the parallelism of the two bars was no longer
essential,..."

Right. That sounds familiar.


Fig 72 shows one flat and one inverted vee way on a cast iron bed.

The difficulties of the early machine builders that Holtzapffel
recorded aren't that much different from those of a homebrew machine
tool maker today, except that we can buy ground drill rod and flat
stock and they could hire cheap child labor for tedious hand fitting.

Right. Maybe you've peeked at my ideas for a ferrocement lathe with
steel
ways. d8-)

(Having finished reading Naaman's _Ferrocement & Laminated
Cementitious
Composites_, I'm less enthusiastic about that construction.)

Significant work has been done on concrete-filled fabricated metal
frames for precision machine tools.

The place to start is MIT professor Alexander H. Slocum
(http://meche.mit.edu:16080/people/index.html?id=80). A good
discussion
and many references may be found in his book "Precision Machine
Design".

Joe Gwinn

Thanks, Joe. I talked to Slocum not too long ago -- maybe a year or
two --
and someone here brought up his book before (maybe you?)

Very likely. I recall posting the reference before. Yes. The thread
was "Epoxy grainite build yer own machine frame" in March 2009.


-- it's on my list
of things to get for my library. I had a copy for a couple of weeks on an
interlibrary loan, and I read what he had to say about long-term
stability
and so on, which helped a lot.

I bet you can borrow it again.

I can, but I'd like to have it. It ain't cheap, and my list of desired books
is long.



I should point out that I was studying and writing about concrete- and
polymer/aggregate-base machines around 30 years ago, and I've visited
manufacturers of them in the US and in France and Italy, mostly around
that
time but as recently as seven years ago. I'm familiar in general with the
various approaches, the materials, and the design philosophies. But I've
never claimed expertise; it was more on the level of a good journalistic
exercise.

The commercial applications are one thing. This wild hair I've been
chasing
has more to do with exploring strategies for building at home, at very
low
cost, and to see what can be done with a material that's intrigued me for
40
years -- ferrocement. The obvious approach to building a machine like
this
would be either a fairly massive, fiber-filled casting or a
screw-tensioned,
post-tensioned cast structure. The former is my next area of study and
it's
a big one. The latter is something I've abandoned because of problems
with
long-term stability and engineering that's trickier than it looks. But it
would be a great way to go, if it wasn't for the stability issue.

Slocum runs hot and cold about concrete versus lots of cast iron, but he
isn't trying for infinite life either.

If it's cheap enough, people will live with something that doesn't last
100 years. Most HSMers won't last that long.

Right. g I don't think that the limitation is the life of the machine, but
rather of dealing with growth or shrinkage over a period of years. There are
ways around it. I just haven't thought it through. But, again, we're talking
about the difference between, say, a South Bend and a Hardinge. You can
build something that will fit into the SB category. But concrete is not the
stuff to use if you want Hardinge.

Then again, if you want Hardinge, you'd better mortgage the house and buy
Hardinge. g I own a South Bend, and it's all I could want for my hobby
machining.



I'm convinced that a concrete machine can deliver ordinary lathe accuracy
and could be perfectly suitable for the hobbyist. Problems crop up when
you
go for high-end, toolroom-grade accuracy and long-term stability. The
polymers are better for that but they're *very* expensive, and defeat the
basic goals I'm starting with.

Anyway, thanks for the tip. I would love to go for this in a big way, but
it
isn't in the cards right now. I'm engaged in conversation with Dr. Senft
on
Stirling engine lubrication, and the outcome is going to eat me up for
months to come. d8-)

Is there a good solution? I recall that this was one of the big issues.

You'll have to read my article, should I succeed in gathering enough info to
write one. There are solutions that work; different solutions for different
realms, from low-temperature-differential types to fractional-horsepower
mule motors, up to 100-hp-plus automotive engines. The solutions are all
different. Senft has put me on to a guy who apparently is one of the world's
experts on automotive Stirlings, and who knows the big-time lubrication
solutions, both for kinematic engines and for free-piston types. I haven't
talked to him yet. I'm looking forward to doing so.



BTW, if anyone is interested in the approach you mention, which is
various
forms of making a light welded or bolted steel structure and filling it
with
concrete, it has possibilities for the home builder. But it's a lot
trickier
than you might think. There are bonding issues and problems with the
different coefficients of expansion between steel and various...er,
"fillings," plus retained-stress issues with the steel itself. And
concrete
grows (or shrinks; I forget) for decades after it's cast. It's not enough
to
matter in building structures but it can be an issue when you're dealing
with thousandths of an inch.

Yes. Slocum goes over this.

The issue is to replicate the static and dynamic stiffness of cast iron
more cheaply (or with less weight) than cast iron.

A fabricated box-beam frame has plenty of static stiffness, but has far
too little damping, so the dynamic stiffness is scant. Filling the
frame is an attempt to sharply increase the damping and thus dynamic
stiffness, to make the chatter threshold more remote.

Joe Gwinn

Yes. But a torsion box (box-beam) made of concrete has lots of natural
damping. As you say, the filled-base commercial machines have been attempts
to build in damping with low shipping weight (and lower costs) for the
machines.

It's a very tricky engineering problem, but it doesn't require a lot of
knowledge or heavy math. It just requires a good feel for materials and
structures, combined with a lot of patient thought and analysis.

--
Ed Huntress

On Nov 25, 9:06*am, Jim Wilkins wrote:
On Nov 25, 7:37*am, "Denis G." wrote:

On Nov 24, 8:04*am, Jim Wilkins wrote:
...
Scroll down to the bottom and look at "take-up" bearings:http://www.baileynet.com/index.php?i...tegory=1000011

jsw

The picture of the "Lincoln miller" seems to have a "Pratt & Whitney"
logo on the bed.-

Here's a little of the interrelationship between the machine builders
of Hartford, which somewhat like Maudslay's group in England:http://www.hogriver.org/issues/v02n03/miracle.htm

jsw

Thanks for that interesting bit of history. I'll have to read more
when I get the time. I didn't realise that Hartford could have become
the "Motor City" and had important rivals to Henry Ford and his
ventures.

On Wed, 25 Nov 2009 04:18:14 -0800 (PST), Jim Wilkins
wrote:

On Nov 24, 11:36*pm, Ned Simmons wrote:
On Tue, 24 Nov 2009 20:38:12 -0500, "Ed Huntress"
...

One problem with tapered roller bearings, depending on how fussy you
are, is that the runout specs on standard bearings is pretty bad
compared to run of the mill ball bearings. And precision grade roller
bearings are horribly expensive and can be difficult to source.

Ned Simmons-

Does bearing runout matter as much if you finish the spindle nose -
after- keying and clamping it in place?

For my version you swap spindles rather than making precise threads
and tapers on the nose, so keying or at least putting the clamp
setscrews back in the same depressions is important.

Probably not as much, but keep in mind that a ball or roller bearing
is not in the same configuration on every revolution -- there's
relative motion between the races and the balls (rollers) such that
the balls (rollers) orbit at a different rate than the rotating race.
Consequently, my understanding is that if you monitor runout with
enough resolution you'll see a component of the runout that's not in
synch with the RPM of the race. As a practical matter, for a
home-built spindle, I wouldn't worry about the effect with normal deep
row ball bearings. In the case of tapered rollers I don't have a good
SWAG one way or the other without doing more research.

--
Ned Simmons

In article ,
"Ed Huntress" wrote:

"Gunner Asch" wrote in message
...
On Wed, 25 Nov 2009 00:47:42 -0500, Ned Simmons
wrote:


Hmm. Is that right? I thought Hardinges had the classic
two-bearing-front,
floating rear setup. But I don't know for sure. Maybe Gunner would know.

It's as I've described. I've been in there and have a picture here in
front of me.


Very early Hardinges had the 2 bearing front..1940s-early 50s
vintage..but since the late 50s..all have been as Ned said.

Thats for manual and microswitch automatics.

Gunner

Thanks, Gunner. It's not that I don't believe Ned, it's just that I *know*
I've seen that two-bearing arrangement on drawings of Hardinge spindles. I
guess it was just the old ones.

Now Ned has me going. g I'm not going to be happy until I figure out what
they're doing with a spindle that contains preloaded bearings at each end.
Something is unusual here. I just called Hardinge; all of my old contacts
are either dead or retired. d8-( (Hardinge was once my client.)

Google on their names? Perhaps they are alive, but bored, and need to
find RCM.

Joe Gwinn

On Nov 25, 3:47*pm, Ned Simmons wrote:
On Wed, 25 Nov 2009 04:18:14 -0800 (PST), Jim Wilkins
...
Consequently, my understanding is that if you monitor runout with
enough resolution you'll see a component of the runout that's not in
synch with the RPM of the race. As a practical matter, for a
home-built spindle, I wouldn't worry about the effect with normal deep
row ball bearings. In the case of tapered rollers I don't have a good
SWAG one way or the other without doing more research.

Ned Simmons

My tentative plan for best accuracy is to cut center points on the
head and tail spindles and run them live until the work is almost to
size, then lock them down and make the final parallelism, size and
surface finish cuts between dead centers, driving the work directly
with a belt or rubber idler. I expect that the unhardened centers
might have to be refinished afterwards.

This applies more to the cylindrical grinding fixture than a homebrew
lathe, since I found an old South Bend headstock with the same spindle
thread as my lathe's to use for a temporary oversized wheel lathe.

jsw

In article ,
"Ed Huntress" wrote:

"Joseph Gwinn" wrote in message
...
In article ,
"Ed Huntress" wrote:

"Joseph Gwinn" wrote in message
...
In article ,
"Ed Huntress" wrote:

"Jim Wilkins" wrote in message
..
.
On Nov 24, 1:04 pm, "Ed Huntress" wrote:
"Jim Wilkins" wrote in message
...
I just checked my two best sources, Holtzapffel #2 and Oscar
Perrigo's
1916 "Lathe Design", ...
...
As I think about this, I'm remembering what I thought about it at
the
time,
30 years ago. I believed then that the issue was the difficulty,
without
planers, mills, or big surface grinders, of getting the four planes
of
a
pair of V-ways coordinated for straight and smooth travel. One way
to
interpret this is that you can adjust the single plane of the flat
way
a
lot
easier than the pair of planes you have with a second V. So to say
that
it
was simpler to correct accuracy with the V-and-flat could just mean
that;
if
the ways are hand-finished, you're correcting accuracy, and
V-and-flat
is
a
lot easier to correct than two V's.

Maybe. g

--
Ed Huntress

If I read Holtzapffel correctly the two sides of inverted vee ways
were at first made separately, joined and aligned afterwards to fit
the fixed and moving poppit heads (headstock and tailstock to us).

Yeah. In the very beginning of modern lathes, the V-and-flat
combinations
were assembled the same way. The first screw-cutting lathes had wood
beds
with bolted-on iron ways, IIRC. (I'm doing this from memory; don't
bite
me.
g)

"This slight width of base does not afford sufficient lateral support
to the heads, which with only moderate force in turning are liable to
vibration; while exact parallelism of the two angular edged bars is
also necessary. Improvement in stability was sought by making one
side
of the bearers flat and broad, fig. 72, with a corresponding flat on
the underside of the lathe heads; retaining one angular side, to give
the direction or common axis. This arrangement also facilitated the
construction, as the parallelism of the two bars was no longer
essential,..."

Right. That sounds familiar.


Fig 72 shows one flat and one inverted vee way on a cast iron bed.

The difficulties of the early machine builders that Holtzapffel
recorded aren't that much different from those of a homebrew machine
tool maker today, except that we can buy ground drill rod and flat
stock and they could hire cheap child labor for tedious hand fitting.

Right. Maybe you've peeked at my ideas for a ferrocement lathe with
steel
ways. d8-)

(Having finished reading Naaman's _Ferrocement & Laminated
Cementitious
Composites_, I'm less enthusiastic about that construction.)

Significant work has been done on concrete-filled fabricated metal
frames for precision machine tools.

The place to start is MIT professor Alexander H. Slocum
(http://meche.mit.edu:16080/people/index.html?id=80). A good
discussion
and many references may be found in his book "Precision Machine
Design".

Joe Gwinn

Thanks, Joe. I talked to Slocum not too long ago -- maybe a year or
two --
and someone here brought up his book before (maybe you?)

Very likely. I recall posting the reference before. Yes. The thread
was "Epoxy grainite build yer own machine frame" in March 2009.


-- it's on my list
of things to get for my library. I had a copy for a couple of weeks on an
interlibrary loan, and I read what he had to say about long-term
stability
and so on, which helped a lot.

I bet you can borrow it again.

I can, but I'd like to have it. It ain't cheap, and my list of desired books
is long.

I've been tempted as well.


I should point out that I was studying and writing about concrete- and
polymer/aggregate-base machines around 30 years ago, and I've visited
manufacturers of them in the US and in France and Italy, mostly around
that
time but as recently as seven years ago. I'm familiar in general with the
various approaches, the materials, and the design philosophies. But I've
never claimed expertise; it was more on the level of a good journalistic
exercise.

The commercial applications are one thing. This wild hair I've been
chasing
has more to do with exploring strategies for building at home, at very
low
cost, and to see what can be done with a material that's intrigued me for
40
years -- ferrocement. The obvious approach to building a machine like
this
would be either a fairly massive, fiber-filled casting or a
screw-tensioned,
post-tensioned cast structure. The former is my next area of study and
it's
a big one. The latter is something I've abandoned because of problems
with
long-term stability and engineering that's trickier than it looks. But it
would be a great way to go, if it wasn't for the stability issue.

Slocum runs hot and cold about concrete versus lots of cast iron, but he
isn't trying for infinite life either.

If it's cheap enough, people will live with something that doesn't last
100 years. Most HSMers won't last that long.

Right. g I don't think that the limitation is the life of the machine, but
rather of dealing with growth or shrinkage over a period of years. There are
ways around it. I just haven't thought it through. But, again, we're talking
about the difference between, say, a South Bend and a Hardinge. You can
build something that will fit into the SB category. But concrete is not the
stuff to use if you want Hardinge.

Then again, if you want Hardinge, you'd better mortgage the house and buy
Hardinge. g I own a South Bend, and it's all I could want for my hobby
machining.

I've been tempted as well. But I like my house, so Clausing will have
to carry on.


I'm convinced that a concrete machine can deliver ordinary lathe accuracy
and could be perfectly suitable for the hobbyist. Problems crop up when
you
go for high-end, toolroom-grade accuracy and long-term stability. The
polymers are better for that but they're *very* expensive, and defeat the
basic goals I'm starting with.

Anyway, thanks for the tip. I would love to go for this in a big way, but
it
isn't in the cards right now. I'm engaged in conversation with Dr. Senft
on
Stirling engine lubrication, and the outcome is going to eat me up for
months to come. d8-)

Is there a good solution? I recall that this was one of the big issues.

You'll have to read my article, should I succeed in gathering enough info to
write one. There are solutions that work; different solutions for different
realms, from low-temperature-differential types to fractional-horsepower
mule motors, up to 100-hp-plus automotive engines. The solutions are all
different. Senft has put me on to a guy who apparently is one of the world's
experts on automotive Stirlings, and who knows the big-time lubrication
solutions, both for kinematic engines and for free-piston types. I haven't
talked to him yet. I'm looking forward to doing so.

Please keep us posted. It's even on topic, too.


BTW, if anyone is interested in the approach you mention, which is
various
forms of making a light welded or bolted steel structure and filling it
with
concrete, it has possibilities for the home builder. But it's a lot
trickier
than you might think. There are bonding issues and problems with the
different coefficients of expansion between steel and various...er,
"fillings," plus retained-stress issues with the steel itself. And
concrete
grows (or shrinks; I forget) for decades after it's cast. It's not enough
to
matter in building structures but it can be an issue when you're dealing
with thousandths of an inch.

Yes. Slocum goes over this.

The issue is to replicate the static and dynamic stiffness of cast iron
more cheaply (or with less weight) than cast iron.

A fabricated box-beam frame has plenty of static stiffness, but has far
too little damping, so the dynamic stiffness is scant. Filling the
frame is an attempt to sharply increase the damping and thus dynamic
stiffness, to make the chatter threshold more remote.

Joe Gwinn

Yes. But a torsion box (box-beam) made of concrete has lots of natural
damping. As you say, the filled-base commercial machines have been attempts
to build in damping with low shipping weight (and lower costs) for the
machines.

It's a very tricky engineering problem, but it doesn't require a lot of
knowledge or heavy math. It just requires a good feel for materials and
structures, combined with a lot of patient thought and analysis.

As I said, Slocum runs hot and cold on this in the book. The savings
were not dramatic, even if he used aluminum weldments for the machine
frame. (Yes, it's a torsion box, bent into a C-form.) I think Slocum
did build such machines, so the tradeoff summary wasn't just a
theoretical musing.

Slocum patented (5,799,924 and 5,743,326) a vibration damper consisting
of a tube with a greased steel rod within, with the space between tube
and greased rod filled with poured-in epoxy resin. The grease acts as a
mold release, so the rod is floating, and later acts as the goop layer
to absorb vibration. I think that this was intended for boring bars, as
an alternative to solid carbide. And one could make the tube from solid
carbide as well.

I suppose one could embed a greased inner box frame inside the box beam
machine frame before filling with resin. From his patent drawings,
Slocum is thinking this way.


Joe Gwinn

On Wed, 25 Nov 2009 10:38:54 -0800 (PST), "Denis G."
wrote:

http://www.hogriver.org/issues/v02n03/miracle.htm


Way cool! Thanks!

Gunner

"Aren't cats Libertarian? They just want to be left alone.
I think our dog is a Democrat, as he is always looking for a handout"
Unknown Usnet Poster

Heh, heh, I'm pretty sure my dog is a liberal - he has no balls.
Keyton

"Joseph Gwinn" wrote in message
...
In article ,
"Ed Huntress" wrote:

"Gunner Asch" wrote in message
...
On Wed, 25 Nov 2009 00:47:42 -0500, Ned Simmons
wrote:


Hmm. Is that right? I thought Hardinges had the classic
two-bearing-front,
floating rear setup. But I don't know for sure. Maybe Gunner would
know.

It's as I've described. I've been in there and have a picture here in
front of me.


Very early Hardinges had the 2 bearing front..1940s-early 50s
vintage..but since the late 50s..all have been as Ned said.

Thats for manual and microswitch automatics.

Gunner

Thanks, Gunner. It's not that I don't believe Ned, it's just that I
*know*
I've seen that two-bearing arrangement on drawings of Hardinge spindles.
I
guess it was just the old ones.

Now Ned has me going. g I'm not going to be happy until I figure out
what
they're doing with a spindle that contains preloaded bearings at each
end.
Something is unusual here. I just called Hardinge; all of my old contacts
are either dead or retired. d8-( (Hardinge was once my client.)

Google on their names? Perhaps they are alive, but bored, and need to
find RCM.

Joe Gwinn

One now works in an unrelated industry, and was the sales manager. Another
is retired in Elmira; I spoke to him last summer -- he's occupied with other
interests. g Of the two tech guys I knew, one passed away and the other I
haven't spoken to for over 20 years, so it would be a little awkward.

Hardinge has had some rough times. I was doing some research (not
engineering) for them a little over two years ago, and not one of the people
I talked to then is still there.

I think we can find out what we need to know without them; I'm not
encouraged by the response of the service (dispatcher, I guess), who made it
pretty clear that no one there would know about the old machines. That work
probably has been taken up by third-party service organizations. Maybe
Gunner knows who that would be.

BTW, I didn't try the parts department, because I'm guessing that they know
parts numbers but not much about the engineering involved.

--
Ed Huntress

On Thu, 26 Nov 2009 13:22:11 -0500, "Ed Huntress"
wrote:



Ok, and thanks for the references. For the moment, I'd like to get straight
in my mind how this Hardinge spindle works. Maybe I can cut to the chase by
asking a couple of questions, since you have the drawing and may be able to
see the details with it.

A lathe spindle has to deal with four forces. First, the major radial load,
which usually is taken out by the front (spindle-nose-end) bearing. Second,
the minor radial load, which typically is the tail-end bearing. The ones I'm
questioning here are the other two: the thrust loads in each direction -- Z+
and Z-.

Which bearing takes out each of these two thrust loads? How far apart are
the front and rear bearings? Are they both single-row types, or is one a
double-row? Finally, do either of the bearings have a split race?

Thanks.

AFAICT, the HLV-H has two identical angular contact bearings spaced a long way
apart with a spacer on the mandrel for the inner races and external clamping
for the outer races. I believe they are back-to-back rather than face-to-face,
but could be wrong.

The HLV has a pair of the same bearings as above back-to-back at the front.
clamped together by the outer races and a deep groove ball bearing at the rear
floating in a bore, but lightly loaded with a wave washer.


The HLV-H design is better than the HLV.

The HLV has a number of gearbox shafts with three bearings fighting against
each other. This results in the fitted C1 bearings coming out more sloppy than
C3 after a few decades. The headstock bearings are much more expensive than
6200C1s though. I don't know if the HLV-H has these problems.


Mark Rand
RTFM

"Mark Rand" wrote in message
...
On Thu, 26 Nov 2009 13:22:11 -0500, "Ed Huntress"

wrote:



Ok, and thanks for the references. For the moment, I'd like to get
straight
in my mind how this Hardinge spindle works. Maybe I can cut to the chase
by
asking a couple of questions, since you have the drawing and may be able
to
see the details with it.

A lathe spindle has to deal with four forces. First, the major radial
load,
which usually is taken out by the front (spindle-nose-end) bearing.
Second,
the minor radial load, which typically is the tail-end bearing. The ones
I'm
questioning here are the other two: the thrust loads in each direction --
Z+
and Z-.

Which bearing takes out each of these two thrust loads? How far apart are
the front and rear bearings? Are they both single-row types, or is one a
double-row? Finally, do either of the bearings have a split race?

Thanks.

AFAICT, the HLV-H has two identical angular contact bearings spaced a long
way
apart with a spacer on the mandrel for the inner races and external
clamping
for the outer races. I believe they are back-to-back rather than
face-to-face,
but could be wrong.

The HLV has a pair of the same bearings as above back-to-back at the
front.
clamped together by the outer races and a deep groove ball bearing at the
rear
floating in a bore, but lightly loaded with a wave washer.


The HLV-H design is better than the HLV.

The HLV has a number of gearbox shafts with three bearings fighting
against
each other. This results in the fitted C1 bearings coming out more sloppy
than
C3 after a few decades. The headstock bearings are much more expensive
than
6200C1s though. I don't know if the HLV-H has these problems.


Mark Rand
RTFM

Ho-kay. Now, the reputation of Hardinge toolroom lathes is that the spindle
typically gets up to about body temperature or slightly above when they're
running and stabilized (this is second-hand info; I've never put my hand on
one). That's quite cool, but not out of reason for near-perfect bearings.

Apologies for doing this all in Fahrenheit and inch measurements, but if the
bearings are separated by, say, 8 inches, the spindle (and the spacer,
assuming it's steel) between them will expand by just under 0.002 in. with a
30 deg. F rise in temperature. (Steel expands at 7.3 x 10^-6 inch per inch,
per degree F, if anyone cares to check my calculations).

How do they cope with that? Does the headstock casting supposedly compensate
perfectly for that growth? Because 0.002 in. is enough to completely unload
any preloaded, high-quality bearings -- or to destroy them if they're each
facing the other way.

--
Ed Huntress

On Thu, 26 Nov 2009 20:45:52 +0000, Mark Rand wrote:

On Thu, 26 Nov 2009 13:22:11 -0500, "Ed Huntress"
wrote:

The HLV has a pair of the same bearings as above back-to-back at the front.
clamped together by the outer races and a deep groove ball bearing at the rear
floating in a bore, but lightly loaded with a wave washer.


Update, caused by going out to the shed and actually looking at the bearings I
took out...

The HLV-H and HLV front bearings are Fafnir 9111W1 angular contact. The HLV
rear is a 9110W1 angular contact.


Mark Rand
RTFM

"Mark Rand" wrote in message
...
On Thu, 26 Nov 2009 20:45:52 +0000, Mark Rand
wrote:

On Thu, 26 Nov 2009 13:22:11 -0500, "Ed Huntress"

wrote:

The HLV has a pair of the same bearings as above back-to-back at the
front.
clamped together by the outer races and a deep groove ball bearing at the
rear
floating in a bore, but lightly loaded with a wave washer.


Update, caused by going out to the shed and actually looking at the
bearings I
took out...

The HLV-H and HLV front bearings are Fafnir 9111W1 angular contact. The
HLV
rear is a 9110W1 angular contact.


Mark Rand
RTFM

Now I'm getting confused. If the HLV has a pair in front and one in the
rear, why is the rear bearing an angular-contact type? I can see that for
the HLVH, based on what's been said here.

--
Ed Huntress

On Thu, 26 Nov 2009 16:06:51 -0500, "Ed Huntress"
wrote:




Ho-kay. Now, the reputation of Hardinge toolroom lathes is that the spindle
typically gets up to about body temperature or slightly above when they're
running and stabilized (this is second-hand info; I've never put my hand on
one). That's quite cool, but not out of reason for near-perfect bearings.

Apologies for doing this all in Fahrenheit and inch measurements, but if the
bearings are separated by, say, 8 inches, the spindle (and the spacer,
assuming it's steel) between them will expand by just under 0.002 in. with a
30 deg. F rise in temperature. (Steel expands at 7.3 x 10^-6 inch per inch,
per degree F, if anyone cares to check my calculations).

How do they cope with that? Does the headstock casting supposedly compensate
perfectly for that growth? Because 0.002 in. is enough to completely unload
any preloaded, high-quality bearings -- or to destroy them if they're each
facing the other way.


I had wondered about that.

Close inspection of the parts diagram (anyone want to give me an HLVH-H so I
know for sure, I missed out on two before I got the HLV), shows that the inner
races are separated by a spacer and clamped between the mandrel nose and the
pulley. The outer races are separated by a spacer closely fitted and keyed to
the headstock casting (can be assumed to be thermally part of it). The front
outer race is restrained on both sides, but the rear outer race is only
restrained on the "inside"

So, assuming the mandrel heats up more rapidly than the headstock casting,
it'll get loose before regaining equilibrium. I don't know how good a fit the
rear outer race is in the headstock, but one must assume that it's free enough
to move before the bearing takes harm. There is no preload spring or similar
shown in the parts diagrams.

This also tends to imply that you should run your Hardinge at your desired
speed for about an hour to heat soak it, before doing work of the highest
precision. But only if you're anal about it!

We had an example where differential expansion ate bearings, a model air
turbine had an imperfect bearing retaining arrangement. Ate two sets of
bearings before they worked out the cause of the problem wasn't the mist
lubrication system. Matched pairs of 7" bore taper roller bearings at £6,000 a
set :-O.



Mark Rand
RTFM

"Joseph Gwinn" wrote in message
...
In article ,
"Ed Huntress" wrote:

"Joseph Gwinn" wrote in message
...
In article ,
"Ed Huntress" wrote:

"Joseph Gwinn" wrote in message
...
In article ,
"Ed Huntress" wrote:

"Jim Wilkins" wrote in message
..
.
On Nov 24, 1:04 pm, "Ed Huntress" wrote:
"Jim Wilkins" wrote in message
...
I just checked my two best sources, Holtzapffel #2 and Oscar
Perrigo's
1916 "Lathe Design", ...
...
As I think about this, I'm remembering what I thought about it at
the
time,
30 years ago. I believed then that the issue was the difficulty,
without
planers, mills, or big surface grinders, of getting the four
planes
of
a
pair of V-ways coordinated for straight and smooth travel. One
way
to
interpret this is that you can adjust the single plane of the
flat
way
a
lot
easier than the pair of planes you have with a second V. So to
say
that
it
was simpler to correct accuracy with the V-and-flat could just
mean
that;
if
the ways are hand-finished, you're correcting accuracy, and
V-and-flat
is
a
lot easier to correct than two V's.

Maybe. g

--
Ed Huntress

If I read Holtzapffel correctly the two sides of inverted vee ways
were at first made separately, joined and aligned afterwards to
fit
the fixed and moving poppit heads (headstock and tailstock to us).

Yeah. In the very beginning of modern lathes, the V-and-flat
combinations
were assembled the same way. The first screw-cutting lathes had
wood
beds
with bolted-on iron ways, IIRC. (I'm doing this from memory; don't
bite
me.
g)

"This slight width of base does not afford sufficient lateral
support
to the heads, which with only moderate force in turning are liable
to
vibration; while exact parallelism of the two angular edged bars
is
also necessary. Improvement in stability was sought by making one
side
of the bearers flat and broad, fig. 72, with a corresponding flat
on
the underside of the lathe heads; retaining one angular side, to
give
the direction or common axis. This arrangement also facilitated
the
construction, as the parallelism of the two bars was no longer
essential,..."

Right. That sounds familiar.


Fig 72 shows one flat and one inverted vee way on a cast iron bed.

The difficulties of the early machine builders that Holtzapffel
recorded aren't that much different from those of a homebrew
machine
tool maker today, except that we can buy ground drill rod and flat
stock and they could hire cheap child labor for tedious hand
fitting.

Right. Maybe you've peeked at my ideas for a ferrocement lathe with
steel
ways. d8-)

(Having finished reading Naaman's _Ferrocement & Laminated
Cementitious
Composites_, I'm less enthusiastic about that construction.)

Significant work has been done on concrete-filled fabricated metal
frames for precision machine tools.

The place to start is MIT professor Alexander H. Slocum
(http://meche.mit.edu:16080/people/index.html?id=80). A good
discussion
and many references may be found in his book "Precision Machine
Design".

Joe Gwinn

Thanks, Joe. I talked to Slocum not too long ago -- maybe a year or
two --
and someone here brought up his book before (maybe you?)

Very likely. I recall posting the reference before. Yes. The thread
was "Epoxy grainite build yer own machine frame" in March 2009.


-- it's on my list
of things to get for my library. I had a copy for a couple of weeks on
an
interlibrary loan, and I read what he had to say about long-term
stability
and so on, which helped a lot.

I bet you can borrow it again.

I can, but I'd like to have it. It ain't cheap, and my list of desired
books
is long.

I've been tempted as well.


I should point out that I was studying and writing about concrete- and
polymer/aggregate-base machines around 30 years ago, and I've visited
manufacturers of them in the US and in France and Italy, mostly around
that
time but as recently as seven years ago. I'm familiar in general with
the
various approaches, the materials, and the design philosophies. But
I've
never claimed expertise; it was more on the level of a good
journalistic
exercise.

The commercial applications are one thing. This wild hair I've been
chasing
has more to do with exploring strategies for building at home, at very
low
cost, and to see what can be done with a material that's intrigued me
for
40
years -- ferrocement. The obvious approach to building a machine like
this
would be either a fairly massive, fiber-filled casting or a
screw-tensioned,
post-tensioned cast structure. The former is my next area of study and
it's
a big one. The latter is something I've abandoned because of problems
with
long-term stability and engineering that's trickier than it looks. But
it
would be a great way to go, if it wasn't for the stability issue.

Slocum runs hot and cold about concrete versus lots of cast iron, but
he
isn't trying for infinite life either.

If it's cheap enough, people will live with something that doesn't last
100 years. Most HSMers won't last that long.

Right. g I don't think that the limitation is the life of the machine,
but
rather of dealing with growth or shrinkage over a period of years. There
are
ways around it. I just haven't thought it through. But, again, we're
talking
about the difference between, say, a South Bend and a Hardinge. You can
build something that will fit into the SB category. But concrete is not
the
stuff to use if you want Hardinge.

Then again, if you want Hardinge, you'd better mortgage the house and buy
Hardinge. g I own a South Bend, and it's all I could want for my hobby
machining.

I've been tempted as well. But I like my house, so Clausing will have
to carry on.


I'm convinced that a concrete machine can deliver ordinary lathe
accuracy
and could be perfectly suitable for the hobbyist. Problems crop up
when
you
go for high-end, toolroom-grade accuracy and long-term stability. The
polymers are better for that but they're *very* expensive, and defeat
the
basic goals I'm starting with.

Anyway, thanks for the tip. I would love to go for this in a big way,
but
it
isn't in the cards right now. I'm engaged in conversation with Dr.
Senft
on
Stirling engine lubrication, and the outcome is going to eat me up for
months to come. d8-)

Is there a good solution? I recall that this was one of the big
issues.

You'll have to read my article, should I succeed in gathering enough info
to
write one. There are solutions that work; different solutions for
different
realms, from low-temperature-differential types to fractional-horsepower
mule motors, up to 100-hp-plus automotive engines. The solutions are all
different. Senft has put me on to a guy who apparently is one of the
world's
experts on automotive Stirlings, and who knows the big-time lubrication
solutions, both for kinematic engines and for free-piston types. I
haven't
talked to him yet. I'm looking forward to doing so.

Please keep us posted. It's even on topic, too.

I will if I get anything useful. There's a big book about the history of the
Philips Stirlings, which I've never seen. I'll have to ask one of the
experts if it contains any good info on lubrication.

The basic story is that free-piston Stirlings are using dynamic gas
bearings -- which is to say, the pistons are designed to center themselves
on a film of the working gas. Low-temperature-differential Stirlings
generally run dry, often with graphite pistons (another issue; it's not as
clear as it seems, because synthetic graphite is not lubricious). Other
bearings in those engines are dry-running ball bearings.

Small stationary engines sometimes are made with oiled bottom ends and, in
the case of beta Stirlings, with Rulon or other syntheic seals to keep the
oil out of the hot end. And sometimes they run dry, too. Here it's important
to avoid lateral loads on the pistons, by using rhombic drives, Scotch
yokes, or other mechanisms that result in straight-line forces applied to
the pistons.

I don't know about the big automotive types. There have been a number of
successful ones, from Ford, Saab, and others, so there must be a way. I'm
looking forward to learning more.

The basic issue, BTW, is that oil that gets into the heat exchangers ruins
their efficiency. And oil that gets into the hot end will carbonize. This is
one of the big engineering problems with Stirlings, as you've apparently
heard.



BTW, if anyone is interested in the approach you mention, which is
various
forms of making a light welded or bolted steel structure and filling
it
with
concrete, it has possibilities for the home builder. But it's a lot
trickier
than you might think. There are bonding issues and problems with the
different coefficients of expansion between steel and various...er,
"fillings," plus retained-stress issues with the steel itself. And
concrete
grows (or shrinks; I forget) for decades after it's cast. It's not
enough
to
matter in building structures but it can be an issue when you're
dealing
with thousandths of an inch.

Yes. Slocum goes over this.

The issue is to replicate the static and dynamic stiffness of cast iron
more cheaply (or with less weight) than cast iron.

A fabricated box-beam frame has plenty of static stiffness, but has far
too little damping, so the dynamic stiffness is scant. Filling the
frame is an attempt to sharply increase the damping and thus dynamic
stiffness, to make the chatter threshold more remote.

Joe Gwinn

Yes. But a torsion box (box-beam) made of concrete has lots of natural
damping. As you say, the filled-base commercial machines have been
attempts
to build in damping with low shipping weight (and lower costs) for the
machines.

It's a very tricky engineering problem, but it doesn't require a lot of
knowledge or heavy math. It just requires a good feel for materials and
structures, combined with a lot of patient thought and analysis.

As I said, Slocum runs hot and cold on this in the book. The savings
were not dramatic, even if he used aluminum weldments for the machine
frame. (Yes, it's a torsion box, bent into a C-form.) I think Slocum
did build such machines, so the tradeoff summary wasn't just a
theoretical musing.

Slocum patented (5,799,924 and 5,743,326) a vibration damper consisting
of a tube with a greased steel rod within, with the space between tube
and greased rod filled with poured-in epoxy resin. The grease acts as a
mold release, so the rod is floating, and later acts as the goop layer
to absorb vibration. I think that this was intended for boring bars, as
an alternative to solid carbide. And one could make the tube from solid
carbide as well.

I suppose one could embed a greased inner box frame inside the box beam
machine frame before filling with resin. From his patent drawings,
Slocum is thinking this way.


Joe Gwinn

If it gets too complicated, it can become a solution in search of a problem.
g When I was writing about machine tools and people were trying to sell me
on the Hexapod, it became one of those. Likewise, an
elliptical-piston-machining lathe I was once involved with.

--
Ed Huntress

On Thu, 26 Nov 2009 16:51:38 -0500, "Ed Huntress"
wrote:



Now I'm getting confused. If the HLV has a pair in front and one in the
rear, why is the rear bearing an angular-contact type? I can see that for
the HLVH, based on what's been said here.

Ditto.

I can only put it down to the fact that the HLV seems to incorporate quite a
lot of design decisions that don't make sense from an engineering point of
view, unless you assume that more expensive is automatically better. Like my
case earlier where three C3 or two C1 bearings would outlast three C1 bearings
on a shaft and other oddities. I guess it is a 60 year old design and there
were many improvements made over the years.

On Thu, 26 Nov 2009 20:45:52 +0000, Mark Rand
wrote:

On Thu, 26 Nov 2009 13:22:11 -0500, "Ed Huntress"
wrote:



Ok, and thanks for the references. For the moment, I'd like to get straight
in my mind how this Hardinge spindle works. Maybe I can cut to the chase by
asking a couple of questions, since you have the drawing and may be able to
see the details with it.

A lathe spindle has to deal with four forces. First, the major radial load,
which usually is taken out by the front (spindle-nose-end) bearing. Second,
the minor radial load, which typically is the tail-end bearing. The ones I'm
questioning here are the other two: the thrust loads in each direction -- Z+
and Z-.

Which bearing takes out each of these two thrust loads? How far apart are
the front and rear bearings? Are they both single-row types, or is one a
double-row? Finally, do either of the bearings have a split race?

Thanks.

AFAICT, the HLV-H has two identical angular contact bearings spaced a long way
apart with a spacer on the mandrel for the inner races and external clamping
for the outer races. I believe they are back-to-back rather than face-to-face,
but could be wrong.

The HLV has a pair of the same bearings as above back-to-back at the front.
clamped together by the outer races and a deep groove ball bearing at the rear
floating in a bore, but lightly loaded with a wave washer.


The HLV-H design is better than the HLV.

The HLV has a number of gearbox shafts with three bearings fighting against
each other. This results in the fitted C1 bearings coming out more sloppy than
C3 after a few decades. The headstock bearings are much more expensive than
6200C1s though. I don't know if the HLV-H has these problems.

No..they dont. But the 2 head stock bearings are still $350 for the
pair..or more.

Gunner



Mark Rand
RTFM

"Aren't cats Libertarian? They just want to be left alone.
I think our dog is a Democrat, as he is always looking for a handout"
Unknown Usnet Poster

Heh, heh, I'm pretty sure my dog is a liberal - he has no balls.
Keyton

On Thu, 26 Nov 2009 23:19:02 +0000, Mark Rand
wrote:

On Thu, 26 Nov 2009 16:06:51 -0500, "Ed Huntress"
wrote:




Ho-kay. Now, the reputation of Hardinge toolroom lathes is that the spindle
typically gets up to about body temperature or slightly above when they're
running and stabilized (this is second-hand info; I've never put my hand on
one). That's quite cool, but not out of reason for near-perfect bearings.

Apologies for doing this all in Fahrenheit and inch measurements, but if the
bearings are separated by, say, 8 inches, the spindle (and the spacer,
assuming it's steel) between them will expand by just under 0.002 in. with a
30 deg. F rise in temperature. (Steel expands at 7.3 x 10^-6 inch per inch,
per degree F, if anyone cares to check my calculations).

How do they cope with that? Does the headstock casting supposedly compensate
perfectly for that growth? Because 0.002 in. is enough to completely unload
any preloaded, high-quality bearings -- or to destroy them if they're each
facing the other way.


I had wondered about that.

Close inspection of the parts diagram (anyone want to give me an HLVH-H so I
know for sure, I missed out on two before I got the HLV), shows that the inner
races are separated by a spacer and clamped between the mandrel nose and the
pulley. The outer races are separated by a spacer closely fitted and keyed to
the headstock casting (can be assumed to be thermally part of it). The front
outer race is restrained on both sides, but the rear outer race is only
restrained on the "inside"


The spacer isnt keyed to anything. Its simply on the spindle tube.
Almost an interference fit.

So, assuming the mandrel heats up more rapidly than the headstock casting,
it'll get loose before regaining equilibrium. I don't know how good a fit the
rear outer race is in the headstock, but one must assume that it's free enough
to move before the bearing takes harm. There is no preload spring or similar
shown in the parts diagrams.

When the spindle gets hot..it expands and presses the bearings
harder..not softer.

This also tends to imply that you should run your Hardinge at your desired
speed for about an hour to heat soak it, before doing work of the highest
precision. But only if you're anal about it!

While they will indeed cut to a couple tenths..few people do.


We had an example where differential expansion ate bearings, a model air
turbine had an imperfect bearing retaining arrangement. Ate two sets of
bearings before they worked out the cause of the problem wasn't the mist
lubrication system. Matched pairs of 7" bore taper roller bearings at £6,000 a
set :-O.



Mark Rand
RTFM

"Aren't cats Libertarian? They just want to be left alone.
I think our dog is a Democrat, as he is always looking for a handout"
Unknown Usnet Poster

Heh, heh, I'm pretty sure my dog is a liberal - he has no balls.
Keyton

In article ,
"Ed Huntress" wrote:

"Joseph Gwinn" wrote in message
...
In article ,
"Ed Huntress" wrote:

[snip]
Anyway, thanks for the tip. I would love to go for this in a big way, but
it isn't in the cards right now. I'm engaged in conversation with Dr.
Senft on
Stirling engine lubrication, and the outcome is going to eat me up for
months to come. d8-)

Is there a good solution? I recall that this was one of the big
issues.

You'll have to read my article, should I succeed in gathering enough info
to
write one. There are solutions that work; different solutions for
different
realms, from low-temperature-differential types to fractional-horsepower
mule motors, up to 100-hp-plus automotive engines. The solutions are all
different. Senft has put me on to a guy who apparently is one of the
world's
experts on automotive Stirlings, and who knows the big-time lubrication
solutions, both for kinematic engines and for free-piston types. I
haven't
talked to him yet. I'm looking forward to doing so.

Please keep us posted. It's even on topic, too.

I will if I get anything useful. There's a big book about the history of the
Philips Stirlings, which I've never seen. I'll have to ask one of the
experts if it contains any good info on lubrication.

The basic story is that free-piston Stirlings are using dynamic gas
bearings -- which is to say, the pistons are designed to center themselves
on a film of the working gas. Low-temperature-differential Stirlings
generally run dry, often with graphite pistons (another issue; it's not as
clear as it seems, because synthetic graphite is not lubricious). Other
bearings in those engines are dry-running ball bearings.

Small stationary engines sometimes are made with oiled bottom ends and, in
the case of beta Stirlings, with Rulon or other syntheic seals to keep the
oil out of the hot end. And sometimes they run dry, too. Here it's important
to avoid lateral loads on the pistons, by using rhombic drives, Scotch
yokes, or other mechanisms that result in straight-line forces applied to
the pistons.

I don't know about the big automotive types. There have been a number of
successful ones, from Ford, Saab, and others, so there must be a way. I'm
looking forward to learning more.

The basic issue, BTW, is that oil that gets into the heat exchangers ruins
their efficiency. And oil that gets into the hot end will carbonize. This is
one of the big engineering problems with Stirlings, as you've apparently
heard.

I had heard that seals were a big problem, and noticed that only NASA
seemed to be able to use Stirling cycle engines for anything, but didn't
know the details.


[snip]

Yes. But a torsion box (box-beam) made of concrete has lots of natural
damping. As you say, the filled-base commercial machines have been
attempts
to build in damping with low shipping weight (and lower costs) for the
machines.

It's a very tricky engineering problem, but it doesn't require a lot of
knowledge or heavy math. It just requires a good feel for materials and
structures, combined with a lot of patient thought and analysis.

As I said, Slocum runs hot and cold on this in the book. The savings
were not dramatic, even if he used aluminum weldments for the machine
frame. (Yes, it's a torsion box, bent into a C-form.) I think Slocum
did build such machines, so the tradeoff summary wasn't just a
theoretical musing.

Slocum patented (5,799,924 and 5,743,326) a vibration damper consisting
of a tube with a greased steel rod within, with the space between tube
and greased rod filled with poured-in epoxy resin. The grease acts as a
mold release, so the rod is floating, and later acts as the goop layer
to absorb vibration. I think that this was intended for boring bars, as
an alternative to solid carbide. And one could make the tube from solid
carbide as well.

I suppose one could embed a greased inner box frame inside the box beam
machine frame before filling with resin. From his patent drawings,
Slocum is thinking this way.


Joe Gwinn

If it gets too complicated, it can become a solution in search of a problem.
g When I was writing about machine tools and people were trying to sell me
on the Hexapod, it became one of those. Likewise, an
elliptical-piston-machining lathe I was once involved with.

My impression is that Slocum has come to this conclusion about concrete
cored machine tools as well. But when you mentioned trying to design
concrete machine tools, I wanted to be sure you knew of this literature.

And his damped boring bar is something a HSM could easily fabricate.

Joe Gwinn

On Thu, 26 Nov 2009 18:28:28 -0800, Gunner Asch
wrote:

On Thu, 26 Nov 2009 23:19:02 +0000, Mark Rand
wrote:


So, assuming the mandrel heats up more rapidly than the headstock casting,
it'll get loose before regaining equilibrium. I don't know how good a fit the
rear outer race is in the headstock, but one must assume that it's free enough
to move before the bearing takes harm. There is no preload spring or similar
shown in the parts diagrams.

When the spindle gets hot..it expands and presses the bearings
harder..not softer.


Have I got it bass ackwards?

I had assumed that the bearings were arranged:-

====


Although, thinking about it.

Given that these are non-separable bearings, rather than fall-apart magneto
type, expansion in the "loosening" direction would still serve to tighten
things up until the point where the bearings broke...and that ain't going to
happen.

Mark Rand
RTFM

On Thu, 26 Nov 2009 18:28:28 -0800, Gunner Asch
wrote:

On Thu, 26 Nov 2009 23:19:02 +0000, Mark Rand
wrote:



Close inspection of the parts diagram (anyone want to give me an HLVH-H so I
know for sure, I missed out on two before I got the HLV), shows that the inner
races are separated by a spacer and clamped between the mandrel nose and the
pulley. The outer races are separated by a spacer closely fitted and keyed to
the headstock casting (can be assumed to be thermally part of it). The front
outer race is restrained on both sides, but the rear outer race is only
restrained on the "inside"


The spacer isnt keyed to anything. Its simply on the spindle tube.
Almost an interference fit.


I didn't mean the spacer on the spindle, I meant the one in the headstock
casting. The parts diagram seems to imply that there's a dowel going through
the top of the headstock casting to hold it in place. Although the book
doesn't show a part number for either part...


Regards
Mark Rand
RTFM

On Fri, 27 Nov 2009 09:51:59 +0000, Mark Rand
wrote:

On Thu, 26 Nov 2009 18:28:28 -0800, Gunner Asch
wrote:

On Thu, 26 Nov 2009 23:19:02 +0000, Mark Rand
wrote:


So, assuming the mandrel heats up more rapidly than the headstock casting,
it'll get loose before regaining equilibrium. I don't know how good a fit the
rear outer race is in the headstock, but one must assume that it's free enough
to move before the bearing takes harm. There is no preload spring or similar
shown in the parts diagrams.

When the spindle gets hot..it expands and presses the bearings
harder..not softer.


Have I got it bass ackwards?

I had assumed that the bearings were arranged:-

====


Although, thinking about it.

Given that these are non-separable bearings, rather than fall-apart magneto
type, expansion in the "loosening" direction would still serve to tighten
things up until the point where the bearings broke...and that ain't going to
happen.

Mark Rand
RTFM

Bingo. G

The folks at Hardinge were pretty damned smart ol farts G

Gunner

"Aren't cats Libertarian? They just want to be left alone.
I think our dog is a Democrat, as he is always looking for a handout"
Unknown Usnet Poster

Heh, heh, I'm pretty sure my dog is a liberal - he has no balls.
Keyton

On Fri, 27 Nov 2009 10:00:08 +0000, Mark Rand
wrote:

On Thu, 26 Nov 2009 18:28:28 -0800, Gunner Asch
wrote:

On Thu, 26 Nov 2009 23:19:02 +0000, Mark Rand
wrote:



Close inspection of the parts diagram (anyone want to give me an HLVH-H so I
know for sure, I missed out on two before I got the HLV), shows that the inner
races are separated by a spacer and clamped between the mandrel nose and the
pulley. The outer races are separated by a spacer closely fitted and keyed to
the headstock casting (can be assumed to be thermally part of it). The front
outer race is restrained on both sides, but the rear outer race is only
restrained on the "inside"


The spacer isnt keyed to anything. Its simply on the spindle tube.
Almost an interference fit.


I didn't mean the spacer on the spindle, I meant the one in the headstock
casting. The parts diagram seems to imply that there's a dowel going through
the top of the headstock casting to hold it in place. Although the book
doesn't show a part number for either part...


Ayup..there is indeed a dowel holding the "spindle cavity" Stuff in the
rough headstock. As its not removable..the thing is simply part of the
manufacturing process and is not intended for removal. Though I did see
one that was partially out once.

They figure the drunk on the forklift hit it about 15 mph..perfect shot
on the end of the collet closer with one fork of a 12,000 lb forklift.

Moved the machine into the next room..right through a wall and the mens
bathroom.....VBG

The Stuff was sticking out about 1.5"

So it was put in pretty damned good.

They pulled the headstock and sent it back to Hardinge. It was returned
about 3 weeks later, all back in good running condition. Didnt even have
to replace the spindle...but it did need a new collet closer.

Good machines indeed

Gunner


Gunner


Regards
Mark Rand
RTFM

"Aren't cats Libertarian? They just want to be left alone.
I think our dog is a Democrat, as he is always looking for a handout"
Unknown Usnet Poster

Heh, heh, I'm pretty sure my dog is a liberal - he has no balls.
Keyton

On Fri, 27 Nov 2009 02:49:04 -0800, Gunner Asch
wrote:

On Fri, 27 Nov 2009 09:51:59 +0000, Mark Rand
wrote:

On Thu, 26 Nov 2009 18:28:28 -0800, Gunner Asch
wrote:

On Thu, 26 Nov 2009 23:19:02 +0000, Mark Rand
wrote:


So, assuming the mandrel heats up more rapidly than the headstock casting,
it'll get loose before regaining equilibrium. I don't know how good a fit the
rear outer race is in the headstock, but one must assume that it's free enough
to move before the bearing takes harm. There is no preload spring or similar
shown in the parts diagrams.

When the spindle gets hot..it expands and presses the bearings
harder..not softer.


Have I got it bass ackwards?

I had assumed that the bearings were arranged:-

====


Although, thinking about it.

Given that these are non-separable bearings, rather than fall-apart magneto
type, expansion in the "loosening" direction would still serve to tighten
things up until the point where the bearings broke...and that ain't going to
happen.

Mark Rand
RTFM

Bingo. G

The folks at Hardinge were pretty damned smart ol farts G

Gunner


You guys have me confused now. I agree with Mark's earlier
interpretation of the assembly drawing, which I assume is the same as
the one I'm looking at. It seems to me that the bearings must be
installed in a normal back-to-back arrangement (with the spacer in
between, of course), otherwise there'd be nothing holding the outer
race of the rear bearing in place. If this is the case, the preload
will fall as the temperature of the inner spacer and spindle rises
above the temp of outer spacer. Am I missing something?

Back-to-back vs. face-to-face mounting:
http://www.lawrencepumps.com/images0...3_i04_img3.gif

--
Ned Simmons

"Mark Rand" wrote in message
news
On Thu, 26 Nov 2009 16:51:38 -0500, "Ed Huntress"

wrote:



Now I'm getting confused. If the HLV has a pair in front and one in the
rear, why is the rear bearing an angular-contact type? I can see that for
the HLVH, based on what's been said here.

Ditto.

I can only put it down to the fact that the HLV seems to incorporate quite
a
lot of design decisions that don't make sense from an engineering point of
view, unless you assume that more expensive is automatically better. Like
my
case earlier where three C3 or two C1 bearings would outlast three C1
bearings
on a shaft and other oddities. I guess it is a 60 year old design and
there
were many improvements made over the years.

If all of this is sinking in correctly, it sounds like the outer spacer is
designed to heat and expand at the same rate as the inner spacer -- or close
enough for it to work. Because it still looks to me like the whole assembly
is going to break or unload if one of them expands significantly faster than
the other.

With the outer spacer, it saves one bearing but adds the spacer. And the
whole thing, I'll bet, was developed experimentally.

To get back to my original questions, that wouldn't work for the home-built
lathe I'm talking about. The complication of holding the outer spacer, and
getting the expansions right, isn't something I think you could do as a
one-shot deal. And the concrete head would add to the differential-spacing
woes.

--
Ed Huntress

On Nov 28, 2:20*am, "Ed Huntress" wrote:
...

To get back to my original questions, that wouldn't work for the home-built
lathe I'm talking about. The complication of holding the outer spacer, and
getting the expansions right, isn't something I think you could do as a
one-shot deal. And the concrete head would add to the differential-spacing
woes.
Ed Huntress

But if you built it yourself and are the only user you know you have
to pay extra attention for problems. You could file the left-hand
bearing seat on the spindle to a moderate press fit so it can slide if
it has to, or not run it long and fast enough to warm up. You could
rub some wax on the spindle nose and shut off if it melts and turns
shiny.

Prototypes are full of gotchas and caveats but they still work well
for the people who built them. You might have to hire (or be) a tech
writer to put together a lengthy manual so someone else could safely
use the machine.

jsw

"Jim Wilkins" wrote in message
...
On Nov 28, 2:20 am, "Ed Huntress" wrote:
...

To get back to my original questions, that wouldn't work for the
home-built
lathe I'm talking about. The complication of holding the outer spacer, and
getting the expansions right, isn't something I think you could do as a
one-shot deal. And the concrete head would add to the differential-spacing
woes.
Ed Huntress

But if you built it yourself and are the only user you know you have
to pay extra attention for problems. You could file the left-hand
bearing seat on the spindle to a moderate press fit so it can slide if
it has to, or not run it long and fast enough to warm up. You could
rub some wax on the spindle nose and shut off if it melts and turns
shiny.

Right. But if the bearing slips, you have no Z-axis stiffness. The spindle
would slide in or out when you took facing cuts or faced the back of a
bearing retainer or whatever on a shaft.

The traditional setup, with two facing, angular-contact bearings at the
front, and one floating bearing at the rear, solves all of those problems.
There isn't enough space between the front bearings for thermal growth to be
a problem. And both thrust loads, Z+ and Z-, are taken out at the front.
Then the rear bearing can float a bit with no loss of axial stiffness. It
needs to be preloaded in the radial direction to maintain radial stiffness,
but there, too, there is more room for slack than at the front.

Prototypes are full of gotchas and caveats but they still work well
for the people who built them. You might have to hire (or be) a tech
writer to put together a lengthy manual so someone else could safely
use the machine.

jsw

On Nov 28, 1:14*pm, "Ed Huntress" wrote:
"Jim Wilkins" wrote in message

...You could file the left-hand
bearing seat on the spindle to a moderate press fit so it can slide if
it has to,...
Right. But if the bearing slips, you have no Z-axis stiffness. The spindle
would slide in or out when you took facing cuts or faced the back of a
bearing retainer or whatever on a shaft.

The traditional setup, with two facing, angular-contact bearings at the
front, and one floating bearing at the rear, solves all of those problems..
There isn't enough space between the front bearings for thermal growth to be
a problem. And both thrust loads, Z+ and Z-, are taken out at the front.
Then the rear bearing can float a bit with no loss of axial stiffness. It
needs to be preloaded in the radial direction to maintain radial stiffness,
but there, too, there is more room for slack than at the front.

jsw

There's no conflict, I suggested a non-precision manual way to make
the rear bearing float without being too loose when you are boot-
strapping the lathe. I'd figure out the preloading details on the
chuck end after a trial assembly to see if the bearings are good
enough. Some combination of easily made spacers and shims ought to
work.

I've found that if I order the parts to build it one way, perhaps not
the absolute best one, they will allow it to be assembled several
other better ways that I think of only after trying the first one. I
do have to know any hard limits like bearing PV and buy to meet them,
but the mounting details can safely wait.

On our plain bearing, leather belt driven South Bends a ball thrust
bearing on the pulley side of the rear/left spindle bearing absorbs
thrust and a threaded shaft clamp on the outside takes up play. The
instructions are to hand-tighten it, then back off 3/8" (of rotation)
and lock the clamp screw. The chuck end is free to slide.

jsw

"Jim Wilkins" wrote in message
...
On Nov 28, 1:14 pm, "Ed Huntress" wrote:
"Jim Wilkins" wrote in message

...You could file the left-hand
bearing seat on the spindle to a moderate press fit so it can slide if
it has to,...
Right. But if the bearing slips, you have no Z-axis stiffness. The spindle
would slide in or out when you took facing cuts or faced the back of a
bearing retainer or whatever on a shaft.

The traditional setup, with two facing, angular-contact bearings at the
front, and one floating bearing at the rear, solves all of those problems.
There isn't enough space between the front bearings for thermal growth to
be
a problem. And both thrust loads, Z+ and Z-, are taken out at the front.
Then the rear bearing can float a bit with no loss of axial stiffness. It
needs to be preloaded in the radial direction to maintain radial
stiffness,
but there, too, there is more room for slack than at the front.

jsw

There's no conflict, I suggested a non-precision manual way to make
the rear bearing float without being too loose when you are boot-
strapping the lathe. I'd figure out the preloading details on the
chuck end after a trial assembly to see if the bearings are good
enough. Some combination of easily made spacers and shims ought to
work.

How do you take out both Z+ and Z- axial loads from one single-row bearing?

--
Ed Huntress


I've found that if I order the parts to build it one way, perhaps not
the absolute best one, they will allow it to be assembled several
other better ways that I think of only after trying the first one. I
do have to know any hard limits like bearing PV and buy to meet them,
but the mounting details can safely wait.

On our plain bearing, leather belt driven South Bends a ball thrust
bearing on the pulley side of the rear/left spindle bearing absorbs
thrust and a threaded shaft clamp on the outside takes up play. The
instructions are to hand-tighten it, then back off 3/8" (of rotation)
and lock the clamp screw. The chuck end is free to slide.

jsw

On Nov 28, 7:03*pm, "Ed Huntress" wrote:
"Jim Wilkins" wrote in message
....

How do you take out both Z+ and Z- axial loads from one single-row bearing?
Ed Huntress

I don't. On Nov 24 I wrote:

"I would try pillow blocks with setscrews or shaft clamps and jam two
of them together to get preloaded angular contact at the working end
of the spindle. Then the spindle (key-slotted shafting) could be
easily swapped so you could weld a plate on one to mount a chuck, for
instance."

The details depend on whatever I find/order/make for a spindle and
bearings and drive pulley.

jsw

"Jim Wilkins" wrote in message
...
On Nov 28, 7:03 pm, "Ed Huntress" wrote:
"Jim Wilkins" wrote in message
....

How do you take out both Z+ and Z- axial loads from one single-row
bearing?
Ed Huntress

I don't. On Nov 24 I wrote:

"I would try pillow blocks with setscrews or shaft clamps and jam two
of them together to get preloaded angular contact at the working end
of the spindle. Then the spindle (key-slotted shafting) could be
easily swapped so you could weld a plate on one to mount a chuck, for
instance."

The details depend on whatever I find/order/make for a spindle and
bearings and drive pulley.

jsw

Oh, then we're talking about two different things. I was still wondering
about applying the single bearing to each end of the spindle, like the
Hardinge HLVH.

--
Ed Huntress

On Nov 28, 7:40*pm, "Ed Huntress" wrote:
"Jim Wilkins" wrote in message

...
On Nov 28, 7:03 pm, "Ed Huntress" wrote:





"Jim Wilkins" wrote in message
...

How do you take out both Z+ and Z- axial loads from one single-row
bearing?
Ed Huntress
I don't. On Nov 24 I wrote:

"I would try pillow blocks with setscrews or shaft clamps and jam two
of them together to get preloaded angular contact at the working end
of the spindle. Then the spindle (key-slotted shafting) could be
easily swapped so you could weld a plate on one to mount a chuck, for
instance."

The details depend on whatever I find/order/make for a spindle and
bearings and drive pulley.

jsw

Oh, then we're talking about two different things. I was still wondering
about applying the single bearing to each end of the spindle, like the
Hardinge HLVH.

--
Ed Huntress

Maybe you could machine shoulders on the spindle and pipe sleeve
spaced for the cold spindle, then place an O ring between the outer
race and its retaining cap on the chuck end. Tighten the retaining cap
if the tool chatters or digs in when turning a left-side shoulder,
loosen it if the spindle binds. There ought to be a compromise where
you can get some work done.

jsw

On Sat, 28 Nov 2009 02:20:12 -0500, "Ed Huntress"
wrote:


"Mark Rand" wrote in message
news
On Thu, 26 Nov 2009 16:51:38 -0500, "Ed Huntress"

wrote:



Now I'm getting confused. If the HLV has a pair in front and one in the
rear, why is the rear bearing an angular-contact type? I can see that for
the HLVH, based on what's been said here.

Ditto.

I can only put it down to the fact that the HLV seems to incorporate quite
a
lot of design decisions that don't make sense from an engineering point of
view, unless you assume that more expensive is automatically better. Like
my
case earlier where three C3 or two C1 bearings would outlast three C1
bearings
on a shaft and other oddities. I guess it is a 60 year old design and
there
were many improvements made over the years.

If all of this is sinking in correctly, it sounds like the outer spacer is
designed to heat and expand at the same rate as the inner spacer -- or close
enough for it to work. Because it still looks to me like the whole assembly
is going to break or unload if one of them expands significantly faster than
the other.

With the outer spacer, it saves one bearing but adds the spacer. And the
whole thing, I'll bet, was developed experimentally.

The HLVH layout is extreme, but some space between the front bearing
pair is not unusual. I'm looking at a cross section of a 10EE
headstock and it appears the spacers are about 2-1/2" long. The
support at the tail is an unspaced pair of angular contact bearings.
Top speed of an EE is about 1000RPM higher than an HLVH.

The bearings at the nose of a Bridgeport spindle are separated perhaps
1-1/2". In this case there's a single deep groove bearing at the top
of the quill. A BP spindle running at top speed gets much hotter than
an HLVH.

Grinder spindles typically have the bearings pairs mounted directly
back-to-back.

--
Ned Simmons

"Ned Simmons" wrote in message
...
On Sat, 28 Nov 2009 02:20:12 -0500, "Ed Huntress"
wrote:


"Mark Rand" wrote in message
news
On Thu, 26 Nov 2009 16:51:38 -0500, "Ed Huntress"

wrote:



Now I'm getting confused. If the HLV has a pair in front and one in the
rear, why is the rear bearing an angular-contact type? I can see that
for
the HLVH, based on what's been said here.

Ditto.

I can only put it down to the fact that the HLV seems to incorporate
quite
a
lot of design decisions that don't make sense from an engineering point
of
view, unless you assume that more expensive is automatically better.
Like
my
case earlier where three C3 or two C1 bearings would outlast three C1
bearings
on a shaft and other oddities. I guess it is a 60 year old design and
there
were many improvements made over the years.

If all of this is sinking in correctly, it sounds like the outer spacer is
designed to heat and expand at the same rate as the inner spacer -- or
close
enough for it to work. Because it still looks to me like the whole
assembly
is going to break or unload if one of them expands significantly faster
than
the other.

With the outer spacer, it saves one bearing but adds the spacer. And the
whole thing, I'll bet, was developed experimentally.

The HLVH layout is extreme, but some space between the front bearing
pair is not unusual. I'm looking at a cross section of a 10EE
headstock and it appears the spacers are about 2-1/2" long. The
support at the tail is an unspaced pair of angular contact bearings.
Top speed of an EE is about 1000RPM higher than an HLVH.

The bearings at the nose of a Bridgeport spindle are separated perhaps
1-1/2". In this case there's a single deep groove bearing at the top
of the quill. A BP spindle running at top speed gets much hotter than
an HLVH.

Grinder spindles typically have the bearings pairs mounted directly
back-to-back.

--
Ned Simmons

That generally agrees with what I've seen, although I haven't had any
spindles apart for a few decades. Thirty degrees F produces about 0.001 in.
of growth in about 5 inches of length. That shouldn't be a problem for
ordinary bearings, which are less that perfect all around; there's a little
room for elastic compression.

As it's been explained to me, the problem becomes more critical as the
bearing class goes up. The Class 9 bearings in a Hardinge HLVH must be very
touchy in terms of the growth they'll tolerate.

--
Ed Huntress

"Jim Wilkins" wrote in message
...
On Nov 28, 7:40 pm, "Ed Huntress" wrote:
"Jim Wilkins" wrote in message

...
On Nov 28, 7:03 pm, "Ed Huntress" wrote:





"Jim Wilkins" wrote in message
...

How do you take out both Z+ and Z- axial loads from one single-row
bearing?
Ed Huntress
I don't. On Nov 24 I wrote:

"I would try pillow blocks with setscrews or shaft clamps and jam two
of them together to get preloaded angular contact at the working end
of the spindle. Then the spindle (key-slotted shafting) could be
easily swapped so you could weld a plate on one to mount a chuck, for
instance."

The details depend on whatever I find/order/make for a spindle and
bearings and drive pulley.

jsw

Oh, then we're talking about two different things. I was still wondering
about applying the single bearing to each end of the spindle, like the
Hardinge HLVH.

--
Ed Huntress

Maybe you could machine shoulders on the spindle and pipe sleeve
spaced for the cold spindle, then place an O ring between the outer
race and its retaining cap on the chuck end. Tighten the retaining cap
if the tool chatters or digs in when turning a left-side shoulder,
loosen it if the spindle binds. There ought to be a compromise where
you can get some work done.

jsw

I'm sure there are many possible solutions. But the old designs have lasted
for several generations, for a reason. Aside from the plain-bearing spindles
(which I have and like -- mine hasn't been adjusted in 50 years, and it is
well within spec), various types of roller bearings have been used
successfully, usually with the thrust taken out in a closely-coupled pair at
the head end.

I don't see it as a big problem.

--
Ed Huntress

On Sat, 28 Nov 2009 22:47:07 -0500, Ned Simmons wrote:

With the outer spacer, it saves one bearing but adds the spacer. And the
whole thing, I'll bet, was developed experimentally.

The HLVH layout is extreme, but some space between the front bearing
pair is not unusual. I'm looking at a cross section of a 10EE
headstock and it appears the spacers are about 2-1/2" long. The
support at the tail is an unspaced pair of angular contact bearings.
Top speed of an EE is about 1000RPM higher than an HLVH.

3000 rpm for the HLV-H
4000 rpm for the DV-59 which uses a smaller spindle and headstock..but
only 2 bearings

Gunner



"Aren't cats Libertarian? They just want to be left alone.
I think our dog is a Democrat, as he is always looking for a handout"
Unknown Usnet Poster

Heh, heh, I'm pretty sure my dog is a liberal - he has no balls.
Keyton

On Nov 28, 11:19*pm, "Ed Huntress" wrote:
"Jim Wilkins" wrote in message
...
I'm sure there are many possible solutions. ...
Ed Huntress

The problem is making the first headstock spindle without another
lathe. Once you have it you can machine a better one.

In my case someone would likely offer me a good lathe cheap *after*
seeing the one I struggled to make.

jsw