Hello to everybody,

we are Italian used machine-tools overhaulers and would appreciate some
help ...

At present we are overhauling a few centerless grinders for a customer of
ours. He told us that similar new machines (Mikrosa "Kronos") now come
with ceramic bearings (with a 10 year guarantee!) fitted on the grinding
wheel spindle and he's asking for the same thing on the machines we are
overhauling and retrofitting for him.

It's a big and heavy spindle: in the last machine we made, we replaced
old bearings with RHP 7214CTR3uLP3 and FAG NNU 4920SK.M.SP.C2 all in hi-
precision class. Spindle weights 500kgs, rotates at 2000RPM with a 50HP
motor.

Has anybody any knowledge or experience in this field? Any suggestion for
tech readings? Can anybody suggest an equivalent ceramic (maybe hybrid)
bearing?

We browsed tech literature and discovered ceramic many advantages ...
what about disadvantages for our application?

Thanks for your time and help.

Best regards,

Roberto Musumeci
Mi.Mu. Mach Tools (Italy)

(remove _no_spam_ to email us ...)

You don't want advice from a newsgroup. You deserve advice from the
application engineers who work for the bearing manufacturers. Responding
to questions like yours is what their job is. I suggest you telephone
the manufacturer's local sales office and ask a sales rep to put you in
contact with an applications engineer.

Grant Erwin

Roberto wrote:

Hello to everybody,

we are Italian used machine-tools overhaulers and would appreciate some
help ...

At present we are overhauling a few centerless grinders for a customer of
ours. He told us that similar new machines (Mikrosa "Kronos") now come
with ceramic bearings (with a 10 year guarantee!) fitted on the grinding
wheel spindle and he's asking for the same thing on the machines we are
overhauling and retrofitting for him.

It's a big and heavy spindle: in the last machine we made, we replaced
old bearings with RHP 7214CTR3uLP3 and FAG NNU 4920SK.M.SP.C2 all in hi-
precision class. Spindle weights 500kgs, rotates at 2000RPM with a 50HP
motor.

Has anybody any knowledge or experience in this field? Any suggestion for
tech readings? Can anybody suggest an equivalent ceramic (maybe hybrid)
bearing?

We browsed tech literature and discovered ceramic many advantages ...
what about disadvantages for our application?

Thanks for your time and help.

Best regards,

Roberto Musumeci
Mi.Mu. Mach Tools (Italy)

(remove _no_spam_ to email us ...)

"Grant Erwin" wrote in message
...
You don't want advice from a newsgroup. You deserve advice from the
application engineers who work for the bearing manufacturers.

Yeah, most people here have mills and lathes only a few times the weight of
his spindle, a few might've turned a workpiece that size, but nobody here
has anything on par with that, that I know of. This is the kind of thing
that needs advice you pay for!

(Planer beds don't count. Different class. G)

Tim

--
"I have misplaced my pants." - Homer Simpson | Electronics,
- - - - - - - - - - - - - - - - - - - - - - --+ Metalcasting
and Games: http://webpages.charter.net/dawill/tmoranwms

On Mon, 31 May 2004 17:33:26 GMT, Roberto
wrote:

Hello to everybody,

we are Italian used machine-tools overhaulers and would appreciate some
help ...

At present we are overhauling a few centerless grinders for a customer of
ours. He told us that similar new machines (Mikrosa "Kronos") now come
with ceramic bearings (with a 10 year guarantee!) fitted on the grinding
wheel spindle and he's asking for the same thing on the machines we are
overhauling and retrofitting for him.

Bearings with ceramic balls are becoming more common to eliminate a
problem with electrical current passing through the balls. Complete
ceramic bearings are available (usually for high heat applications or
applications where lubrication is a problem) but you're talking
EXPENSIVE. I suggest you contact the engineering department of any of
the major bearing manufacturers (NTN, NSK, SKF, FAG) in your area and
ask their opinion for your specific application.

A company local to me here in SoCal makes the ceramic roller cam followers
used in some high-end diesel engines. My guess is these are the highest
volume production, cheapest ceramic roller bearing systems in use. Given
the beating that happens in diesel engines, this seems like about the right
product for you.

The company also makes the ceramic insert plates for body armor, a
very popular upgrade in Iraq. IIRC the name is something like "Ceredyne".

Call them and ask about your bearing application.

"Roberto" wrote in message
.. .
Hello to everybody,

we are Italian used machine-tools overhaulers and would appreciate some
help ...

At present we are overhauling a few centerless grinders for a customer of
ours. He told us that similar new machines (Mikrosa "Kronos") now come
with ceramic bearings (with a 10 year guarantee!) fitted on the grinding
wheel spindle and he's asking for the same thing on the machines we are
overhauling and retrofitting for him.

It's a big and heavy spindle: in the last machine we made, we replaced
old bearings with RHP 7214CTR3uLP3 and FAG NNU 4920SK.M.SP.C2 all in hi-
precision class. Spindle weights 500kgs, rotates at 2000RPM with a 50HP
motor.

Has anybody any knowledge or experience in this field? Any suggestion for
tech readings? Can anybody suggest an equivalent ceramic (maybe hybrid)
bearing?

We browsed tech literature and discovered ceramic many advantages ...
what about disadvantages for our application?

Thanks for your time and help.

Best regards,

Roberto Musumeci
Mi.Mu. Mach Tools (Italy)

(remove _no_spam_ to email us ...)

On Wed, 2 Jun 2004 08:05:13 -0700, (daniel
peterman) wrote:

Question
How are the balls in ball bearings inserted between the the inner and
outer races without damaging any parts?
The inner and outer races are "pinched" together, balls are inserted
then the inner race is snapped into position which forces the balls
into place. Next the retainer is installed to keep the balls spaced
This is the procedure for Conrad style bearings. Max types are done
the same except there is a filler slot in the inner and outer race
through which a few additional balls are added..