I remember a discussion quite a while ago in RCM, and a term being mentioned
that is the name for this condition, but I can't remember it (or find it in
my saved posts).

When the bearing and or shaft contact surfaces get to a point of wear, the
shaft no longer spins around it's center axis, but instead, starts this
chatter as it rattles it's way around the inside circumference of the
bearing.

Hopefully, someone will know this term, Thanks,

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html

"Wild_Bill" wrote in message
...
I remember a discussion quite a while ago in RCM, and a term being
mentioned that is the name for this condition, but I can't remember it (or
find it in my saved posts).

When the bearing and or shaft contact surfaces get to a point of wear, the
shaft no longer spins around it's center axis, but instead, starts this
chatter as it rattles it's way around the inside circumference of the
bearing.

Hopefully, someone will know this term, Thanks,

--
WB
.........
metalworking projects
www.kwagmire.com/metal_proj.html



In a genuine hydrodynamic bearing there's an instability known as oil whirl.
If it's chatter or rattling as the shaft bounces round a large clearance I
think I would call it just that. It might be associated with a resonance.

On Mon, 20 Jul 2009 14:32:54 -0400, "Wild_Bill"
wrote:

I remember a discussion quite a while ago in RCM, and a term being mentioned
that is the name for this condition, but I can't remember it (or find it in
my saved posts).

When the bearing and or shaft contact surfaces get to a point of wear, the
shaft no longer spins around it's center axis, but instead, starts this
chatter as it rattles it's way around the inside circumference of the
bearing.

Hopefully, someone will know this term, Thanks,

Precession?

--
Ned Simmons

When the bearing and or shaft contact surfaces get to a point of wear, the
shaft no longer spins around it's center axis, but instead, starts this
chatter as it rattles it's way around the inside circumference of the
bearing.

Hopefully, someone will know this term, Thanks,

How about."Its going to break soon. very soon."

Karl

"Wild_Bill" wrote in message
...
I remember a discussion quite a while ago in RCM, and a term being
mentioned that is the name for this condition, but I can't remember it (or
find it in my saved posts).

When the bearing and or shaft contact surfaces get to a point of wear, the
shaft no longer spins around it's center axis, but instead, starts this
chatter as it rattles it's way around the inside circumference of the
bearing.

Hopefully, someone will know this term, Thanks,

--
WB
.........
metalworking projects
www.kwagmire.com/metal_proj.html



FUBAR?

That could've been it, Ned, but I don't remember.

Someone else had asked if nutation could be the term, which is mentioned in
the definition of precession.

In the example of the shaft in the lightly worn bearing, the true centerline
of the shaft begins to orbit, but not smoothly, hence the chatter-like
noise.

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html


"Ned Simmons" wrote in message
...
On Mon, 20 Jul 2009 14:32:54 -0400, "Wild_Bill"
wrote:

I remember a discussion quite a while ago in RCM, and a term being
mentioned
that is the name for this condition, but I can't remember it (or find it
in
my saved posts).

When the bearing and or shaft contact surfaces get to a point of wear, the
shaft no longer spins around it's center axis, but instead, starts this
chatter as it rattles it's way around the inside circumference of the
bearing.

Hopefully, someone will know this term, Thanks,

Precession?

--
Ned Simmons

Maybe "critical speed" from Machinery's Handbook or "loose" from Murphy's
text.

Hul

Wild_Bill wrote:
That could've been it, Ned, but I don't remember.

Someone else had asked if nutation could be the term, which is mentioned in
the definition of precession.

In the example of the shaft in the lightly worn bearing, the true centerline
of the shaft begins to orbit, but not smoothly, hence the chatter-like
noise.

--
WB
.........
metalworking projects
www.kwagmire.com/metal_proj.html


"Ned Simmons" wrote in message
...
On Mon, 20 Jul 2009 14:32:54 -0400, "Wild_Bill"
wrote:

I remember a discussion quite a while ago in RCM, and a term being
mentioned
that is the name for this condition, but I can't remember it (or find it
in
my saved posts).

When the bearing and or shaft contact surfaces get to a point of wear, the
shaft no longer spins around it's center axis, but instead, starts this
chatter as it rattles it's way around the inside circumference of the
bearing.

Hopefully, someone will know this term, Thanks,

Precession?

--
Ned Simmons

Wild_Bill wrote:
I remember a discussion quite a while ago in RCM, and a term being
mentioned that is the name for this condition, but I can't remember it
(or find it in my saved posts).

When the bearing and or shaft contact surfaces get to a point of wear,
the shaft no longer spins around it's center axis, but instead, starts
this chatter as it rattles it's way around the inside circumference of
the bearing.

Hopefully, someone will know this term, Thanks,

I dont remember, but early turbocharger development experienced this,
and their solution was to let the bearing float in its housing on a film
of oil that damped it out.

In article ,
"newshound" wrote:

"Wild_Bill" wrote in message
...
I remember a discussion quite a while ago in RCM, and a term being
mentioned that is the name for this condition, but I can't remember it (or
find it in my saved posts).

When the bearing and or shaft contact surfaces get to a point of wear, the
shaft no longer spins around it's center axis, but instead, starts this
chatter as it rattles it's way around the inside circumference of the
bearing.

Hopefully, someone will know this term, Thanks,

--
WB
.........
metalworking projects
www.kwagmire.com/metal_proj.html



In a genuine hydrodynamic bearing there's an instability known as oil whirl.
If it's chatter or rattling as the shaft bounces round a large clearance I
think I would call it just that. It might be associated with a resonance.

I recall it as oil swirl, but it's the same thing.

Joe Gwinn

I think that resonance is an aspect of the condition, as in an application
with a small motor, where the noise is more likely to occur at a certain
speed.

The sizes of motors where I've heard these noises are typically small enough
to fit in the palm of a hand.. many are fan motors without side-loading of
the output shafts.
I've never really been certain if the noises emenate from the output end
bearing or the bearing at the opposite end. One might assume that the output
end bearing would have more wear than the tail end bearing.

As speed changes take place, there may be a significant change in forces on
the motor shaft, similar to making changes in the overhang load.

In the example of fans, at some point the speed of the fan blades (real
metal blades more-so) would probbly exhibit a gyro effect, which I think
would tend to damp or cancel the noise-causing chatter.

The range of the low frequency growl may be beyond some folks' hearing, but
the noises are very noticeable to me.

I've been thinking that the term ended in -ing or -tion.

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html


"newshound" wrote in message
...


"Wild_Bill" wrote in message
...
When the bearing and or shaft contact surfaces get to a point of wear,
the shaft no longer spins around it's center axis, but instead, starts
this chatter as it rattles it's way around the inside circumference of
the bearing.


In a genuine hydrodynamic bearing there's an instability known as oil
whirl. If it's chatter or rattling as the shaft bounces round a large
clearance I think I would call it just that. It might be associated with a
resonance.

In the sort of light duty applications where I've encounterd the noise,
there is no immediate threat of failure. This condition can continue for
years, with the worst factor being slightly reduced performance, and the
annoyance of the noise.

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html


"Karl Townsend" wrote in message
anews.com...
When the bearing and or shaft contact surfaces get to a point of wear,
the shaft no longer spins around it's center axis, but instead, starts
this chatter as it rattles it's way around the inside circumference of
the bearing.

Hopefully, someone will know this term, Thanks,

How about."Its going to break soon. very soon."

Karl

The FU part isn't very accurate, other than a deterioration of silent
operation.

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html



"Calif Bill" wrote in message
m...

"Wild_Bill" wrote in message
...
I remember a discussion quite a while ago in RCM, and a term being
mentioned that is the name for this condition, but I can't remember it (or
find it in my saved posts).

When the bearing and or shaft contact surfaces get to a point of wear,
the shaft no longer spins around it's center axis, but instead, starts
this chatter as it rattles it's way around the inside circumference of
the bearing.

Hopefully, someone will know this term, Thanks,

--
WB
.........
metalworking projects
www.kwagmire.com/metal_proj.html



FUBAR?

"Wild_Bill" wrote in message
...
The FU part isn't very accurate, other than a deterioration of silent
operation.

--
WB
.........
metalworking projects
www.kwagmire.com/metal_proj.html



"Calif Bill" wrote in message
m...

"Wild_Bill" wrote in message
...
I remember a discussion quite a while ago in RCM, and a term being
mentioned that is the name for this condition, but I can't remember it
(or find it in my saved posts).

When the bearing and or shaft contact surfaces get to a point of wear,
the shaft no longer spins around it's center axis, but instead, starts
this chatter as it rattles it's way around the inside circumference of
the bearing.

Hopefully, someone will know this term, Thanks,

--
WB
.........
metalworking projects
www.kwagmire.com/metal_proj.html



FUBAR?



No the FU is appropriate. Used to work on Teletype ASR33. They were a
light duty printer and NCR used them for I/O consol printers on a mainframe.
They would wear and rattle and print crap. Was FUed. And they were the
crap to rebuild.

"Calif Bill" wrote in message
m...

"Wild_Bill" wrote in message
...
The FU part isn't very accurate, other than a deterioration of silent
operation.

--
WB
.........
metalworking projects
www.kwagmire.com/metal_proj.html



"Calif Bill" wrote in message
m...

"Wild_Bill" wrote in message
...
I remember a discussion quite a while ago in RCM, and a term being
mentioned that is the name for this condition, but I can't remember it
(or find it in my saved posts).

When the bearing and or shaft contact surfaces get to a point of wear,
the shaft no longer spins around it's center axis, but instead, starts
this chatter as it rattles it's way around the inside circumference of
the bearing.

Hopefully, someone will know this term, Thanks,

--
WB
.........
metalworking projects
www.kwagmire.com/metal_proj.html



FUBAR?



No the FU is appropriate. Used to work on Teletype ASR33. They were a
light duty printer and NCR used them for I/O consol printers on a
mainframe. They would wear and rattle and print crap. Was FUed. And they
were the crap to rebuild.


Oops, wrong number. They were receive only. RO33.

Calif Bill wrote:

No the FU is appropriate. Used to work on Teletype ASR33. They were a
light duty printer and NCR used them for I/O consol printers on a
mainframe. They would wear and rattle and print crap. Was FUed. And they
were the crap to rebuild.


Oops, wrong number. They were receive only. RO33.


Be glad they weren't Kleinschmidt printers.


--
You can't have a sense of humor, if you have no sense!

Calif Bill wrote:

No the FU is appropriate. Used to work on Teletype ASR33. They were a
light duty printer and NCR used them for I/O consol printers on a mainframe.
They would wear and rattle and print crap. Was FUed. And they were the
crap to rebuild.



A friend of mine got hold of a genuine Teletype maint manual for the
ASR33, and I was blown away (we all were) to discover the power-on
lifetime of that model was 2 months. It needed a complete shop rebuild
at one month, and was to be scrapped out at 2 months. This would
presumably be a situation where the unit was actually printing a fair
bit of that time, so in light use they would last 6 months or more.

Well, that DID explain why the computing center needed so DAMN MUCH
maintenance on those things. They made a pretty quick decision to move
away from ASR33's as remote terminals, and go to video terminals and
large shared printers, one per remote facility.

Jon

Jerry Wass wrote:
Wild_Bill wrote:
I remember a discussion quite a while ago in RCM, and a term being
mentioned that is the name for this condition, but I can't remember it
(or find it in my saved posts).

When the bearing and or shaft contact surfaces get to a point of wear,
the shaft no longer spins around it's center axis, but instead, starts
this chatter as it rattles it's way around the inside circumference of
the bearing.

Hopefully, someone will know this term, Thanks,

I dont remember, but early turbocharger development experienced this,
and their solution was to let the bearing float in its housing on a film
of oil that damped it out.
Yes, turbochargers definitely run above critical speed, and so will spin
on an axis through their center of gravity, and to hell with where the
center of the shafts were in relation to that. Any attempt to force the
rotor to spin on the shaft axis will just break the shaft.

This is a different condition than bearing swirl, but can lead to some
of the same problems.

Jon

On Thu, 23 Jul 2009 18:07:41 -0500, Jon Elson
wrote:

ASR33
When I first started in an accounts payable office (1958), they had me
checking invoices using a Sunstrand mechanical adding machine. To
multiply, you held the add key down for the 1 - 9 cycles then shifted
and held the add key again, so to multiply by 99, you added 9 times,
shifted and added 9 more times. Anyhow, I was using at least 1 roll of
tape per day, and about once per week the print mechanism - vertical
element with 10 spring loaded number hammers - would disintegrate, and
the machine went on the shelf for the service tech's next visit. My
record was eight machines in one week.
Incidentally, I have one of these machines, bought new in 1938
downstairs. I should get it out and see if it still works - it was
good the last time I used it in 1972!
Gerry :-)}
London, Canada

"Jon Elson" wrote in message
...
Calif Bill wrote:

No the FU is appropriate. Used to work on Teletype ASR33. They were a
light duty printer and NCR used them for I/O consol printers on a
mainframe. They would wear and rattle and print crap. Was FUed. And
they were the crap to rebuild.

A friend of mine got hold of a genuine Teletype maint manual for the
ASR33, and I was blown away (we all were) to discover the power-on
lifetime of that model was 2 months. It needed a complete shop rebuild at
one month, and was to be scrapped out at 2 months. This would presumably
be a situation where the unit was actually printing a fair bit of that
time, so in light use they would last 6 months or more.

Well, that DID explain why the computing center needed so DAMN MUCH
maintenance on those things. They made a pretty quick decision to move
away from ASR33's as remote terminals, and go to video terminals and large
shared printers, one per remote facility.

Jon

In their designed role, they lasted a long time. Get a message, turns on,
prints message, turns off. Maybe a minute. Maybe you got 1-2 messages a
day. On the Mainframe, they powered up and ran 24/7. We finally got
hardened shafts and the rebuilds got fewer.

Jon Elson wrote:
Calif Bill wrote:

No the FU is appropriate. Used to work on Teletype ASR33. They were
a light duty printer and NCR used them for I/O consol printers on a
mainframe. They would wear and rattle and print crap. Was FUed. And
they were the crap to rebuild.


A friend of mine got hold of a genuine Teletype maint manual for the
ASR33, and I was blown away (we all were) to discover the power-on
lifetime of that model was 2 months. It needed a complete shop rebuild
at one month, and was to be scrapped out at 2 months. This would
presumably be a situation where the unit was actually printing a fair
bit of that time, so in light use they would last 6 months or more.

I fixed my share of ASR33's. Kept clean and lubricated
once a month, they would last far longer than that.

They weren't the most elegant piece of equipment but
they did the job and most of my customers could not
afford anything better.

On Jul 24, 1:21*pm, Jim Stewart wrote:
Jon Elson wrote:
Calif Bill wrote:
..........
A friend of mine got hold of a genuine Teletype maint manual for the
ASR33, and I was blown away (we all were) to discover the power-on
lifetime of that model was 2 months. *...

I fixed my share of ASR33's. *Kept clean and lubricated
once a month, they would last far longer than that.

From a 1968 ASR33 manual:

LUBRICATION INTERVAL IN WEEKS
BASED ON 5-DAY WEEK
......
SPEED 0-8 HRS 8-16 HRS 16-24 HRS
60 WPM 39 26 13
100WPM 26 13 6

jsw

Jim Wilkins wrote:
On Jul 24, 1:21 pm, Jim Stewart wrote:
Jon Elson wrote:
Calif Bill wrote:
..........
A friend of mine got hold of a genuine Teletype maint manual for the
ASR33, and I was blown away (we all were) to discover the power-on
lifetime of that model was 2 months. ...
I fixed my share of ASR33's. Kept clean and lubricated
once a month, they would last far longer than that.

From a 1968 ASR33 manual:

LUBRICATION INTERVAL IN WEEKS
BASED ON 5-DAY WEEK
.....
SPEED 0-8 HRS 8-16 HRS 16-24 HRS
60 WPM 39 26 13
100WPM 26 13 6

I worked for DEC field service in the early
70's. All of my contract maintenance
customers were using ASR33's and they all
got a monthly PM that included lubrication.