| Are your tapers the
same as Timken? Are they interchangeable with Timken? |
|
NTN tapers with the prefix 4T- or ET- and
all NTN-Bower tapers are Timken interchangeable. |
|
| What is the Designation
for Sets (pairs) on your angular contact bearings? |
|
Paired arrangements for angular contact
bearings are designated as D2 (universal flush ground
pair), DB (matched back-to-back pair), DF (Matched
face-to-face pair) and DT (matched tandem pair). |
|
| What is the nomenclature
for Precision Bearings (P4, P5, Tolerances)? |
|
NTN follows the ISO precision tolerance
classes of P0, P6, P5, P4 and P2 which are equivalent
to ABMA classes ABEC 1, ABEC 3, ABEC 5, ABEC 7 and
ABEC 9. |
|
| What is the difference
between T & D1 or what is the designation for
an oil hole? |
|
D1 always denotes a relube feature (any
bearing). T is old nomenclature for inch dimensioned
bearing units housings with a relube feature. |
|
| What is/are the standard
greases? |
|
2AS (Shell Alvania 2S), 5K (Kyodo Multemp
SRL) and 3AS (Shell Alvania 3S) are considered NTN
standard greases: L627 (Polyrex EM) is the current
standard grease for most aftermarket inventory.
5K (Kyodo Multemp SRL) is the standard for micro
bearings. 3AS (Shell Alvania 3S) is the standard
in bearing units. |
|
| What is good high temperature
grease? |
|
NTN has close to 700 greases listed. To
pick one for a specific application requires more
application information. |
|
| What is the designation
for a bronze cage on cylindricals? |
|
Usually a G1 suffix is used to indicate
a bronze cage in a cylindrical roller bearing. In
rare applications an L1 type cage has been used
as well. |
|
| What is the designation
for a tapered bore on sphericals? |
|
A tapered bore on any NTN bearing (except
tapered roller bearings) is a K (1 to 12 ratio)
or K30 (1 to 30 ratio) suffix. |
|
| What does CE or C0
fit mean? |
|
NTN does not use "CE" or "C0".
These are competitor terms for electric motor and
normal internal clearances. Clearance does not indicate
any type of fit. |
|
| What does V1 mean at
the end of the deep groove ball bearing nomenclature? |
|
For NTN "V1" stands for the first
variation on this basic part number. This suffix
lettering does not indicate any specific features.
A print will have to be reviewed to see what is
not standard. |
|
| What does U3A mean
at the end of the deep groove ball bearing nomenclature? |
|
In a part number like 6313ZZC3/2AU3A the
"U3A" can be a packaging code or specific
customer identification code. This does not affect
the bearing features. |
|
| What does LD1NR mean? |
|
LD1NR is the current suffix used on cylindrical
outer ring bearing unit inserts. The "L"
indicates it meets the new Japanese Industrial Specifications.
The "D1" indicates it has a relube feature.
The "NR" means it has a snap ring groove
and snap ring on the outer diameter. This new suffix
(LD1NR) will replace the older suffix D1NR on all
future stock orders on this type of bearing. |
|
| Are tapered bearings
case carburized? |
|
All Bower tapers and NTN tapers with the
prefix; 4T-, ET- or E- are case carburized. ISO
tapers with a "U" suffix and NTN tapers
not having a previously mentioned prefix will be
through hardened. |
|
| Does internal clearance
effect the bearing precision (C3 vs P3)? |
|
C3 is an internal clearance, or the amount
of internal free space between the rolling elements
and the raceways of a bearing. P3 does not exist.
P6 is an ISO tolerance class equivalent to ABEC
3, or the accuracy the bearing is manufactured to.
Clearance does not affect tolerance and tolerance
does not affect clearance. |
|
| Does NTN make tapered
roller assemblies? |
|
Both NTN and NTN-Bower make 2 and 4 row
assemblies, some of which can be found in the NTN-Bower
catalog and the NTN Large Bearing catalog (2250/E). |
|
| Does NTN make extra
precision tapered roller bearings? |
|
NTN does make some select sizes of tapers
in high precision classes (ie. -3, -0, -00 etc.). |
|
| What is the recommended
end play for tapered roller bearings? |
|
End play is application specific, or preset
in the case of NA type taper assemblies. The machine
manufacturers recommendations should be followed.
For new designs please contact NTN engineering. |
|
| Which grease is best
suited for most general bearing? |
|
The current NTN standard grease for unknown
aftermarket applications is L627 (Exxon-Mobil Polyrex
EM). In most cases a good general purpose lithium
or polyurea based grease will work. |
|
| Load ratings seem to
vary from manufacturer to manufacturer, is there
a single method that can be used to compare like
styles of bearings? |
|
Load ratings don't really vary from among
manufacturers, the methods used to calculate load
ratings is different. Some manufacturers use the
ABMA standard, some use the US Industry standard,
some use equivalent dynamic load calculations. In
general if the internal design is the same the load
ratings will be equivalent. |
|
| What factors should
be considered when choosing a bearing? |
|
All application data (loads, speeds, orientation,
etc.), intended use, and environment. |
|
| How much grease is
too much? |
|
For general applications a grease fill
of 30% of the free space in the bearing seems to
be accepted as standard by most manufacturers. Slow
speed applications in harsh environments (such as
agricultural machinery) can sometimes require a
larger fill. High speed applications (ie. hand tools)
can require a lesser fill. Check with NTN engineering
for any special requirements. |
|
| Where is the nearest
distributor or field sales person? |
|
Contact your regional sales office listed
on the back of any NTN catalog (or here
on this Web site) and they can put you in touch
with the area sales representative or local distributor. |
|
| Explain the difference
between C3 and normal clearance? |
|
Clearance classes are established by the
ABMA. C3 is a clearance specification one class
larger than "C Normal" sometimes referred
to as "C0" in deep groove radial ball
bearings. |
|
| What does the term
"electric motor quality" mean? |
|
The term "electric motor quality"
is freely used in describing bearings that meet
a perceived "higher" level of quality
than the standard ABEC1 bearing. Contact NTN marketing
for an Electric Motor Quality brochure. |
|
| Where are specific
bearing types manufactured, plant by plant? |
|
Due to the size of NTN, the answers to
this are too numerous to list. Contact NTN engineering
for specific bearing inquires. |
|
| Does NTN have field
engineering support? How does a visit get scheduled? |
|
NTN does provide engineering field support
to its customers. Contact your local NTN sales representative
to arrange a visit. |
|
| Is the Ultra Class
mounted unit going to be available in metric sizes? |
|
Contact the NTN Marketing department. |
|
| Can a metric insert
fit into the Ultra Class housing? |
|
Any metric 200 series bearing insert with
an "A-" prefix can be installed in the
appropriate sized Ultra Class housing. |
|
| What bearing types
does NTN consider their strong points? |
|
Contact the NTN Marketing department. |
|
| Does NTN have any OEM
programs similar to Timken? |
|
Contact the NTN Sales department. |
|
| Are BCA parts/drawings
going to be available? |
|
Contact the NTN Marketing department. A
new BCA dimensional catalog is under construction.
Individual prints can be requested through NTN engineering. |
|
| Is there a chart that
shows radial clearance ranges in both metric &
inches? |
|
NTN does not currently publish inch dimensioned
clearance tables. |
|
| What is preload? |
|
Preload is an initial load or "negative
clearance" given to a bearing before or during
operation. This results in the rolling element and
raceway surfaces being under constant elastic compressive
forces at their contact points. This has the effect
of making the bearing extremely rigid so that even
when load is applied to the bearing , radial or
axial shaft displacement is minimized. |
|
| What is the difference
between LLB & LLU seals? |
|
The "LB" seal is a non-contact
seal for reduced torque or higher speed requirements.
The "LU" seal is contact seal for better
grease contamination control, but the contact friction
increases torque and lowers the limiting speed. |
|
| What is the 4T prefix
used for? |
|
The 4T- prefix designates a taper bearing
that is made of a special grade of case hardened
steel and is interchangeable with other manufacturers
taper with the same part number. |
|
| What is the difference
between B type sphericals and E type? |
|
The type "B" spherical has asymmetric
rollers guided by an inner ring center rib for better
skewing control. The "E" type spherical
employs larger symmetric rollers (for increased
load capacity) guided by a molded resin cage. |
|
| Does NTN make sealed
sphericals? |
|
NTN makes several series of sealed spherical
bearings, the WA22200 series, the MX-W22200 and
various specials. |
|
| Does NTN make split
sphericals? |
|
NTN has made split spherical as special
orders. These bearings start with a 2PE ----. Please
consult your NTN sales representative for your applications. |
|
| Does NTN make angular
contact bearings? |
|
NTN makes a full line of standard and high
speed angular contact bearings. |
|
| Does NTN make angular
contact bearings with steel cages? |
|
NTN makes a selection of cage options,
including steel for its angular contact bearings. |
|
| Why does NTN use asymmetric
rollers in their sphericals…is there an advantage? |
|
NTN's standard spherical roller bearing
is a B-type design. This type of bearing has asymmetric
rollers that have the advantage of reduced roller
skewing. This allows the bearing to run cooler at
higher speeds than other spherical designs. |
|
| Is it safe to use a
C3 fit in place of a standard fit? |
|
C3 is not a fit, it is an internal clearance.
Fit is how tight or loose the shaft and housing
hold the bearing in place. In most electric motor
rebuild applications a C3 clearance can be used
in place of a normal clearance. Contact NTN engineering
for other applications. |
|
| What grease can be
used when performing maintenance on mounted units? |
|
Standard bearing unit inserts are prelubed
with a lithium based (Shell Alvania 3S) grease.
Relube should be a grease with the same base (lithium). |
|
| What does each grease
code identify? |
|
The grease code on a bearing number tells
us the manufacturer, type and quantity. |
|
| What is the difference
between ABEC 3 and C3? Does the fit get better going
up to C4 or down to C2? |
|
ABEC 3 is an AMBA tolerance class. C3 is
an internal clearance specification. Fit is the
relationship between the bearing bore and outside
diameters to the housing bore and shaft outside
diameter. Tolerance, clearance and fit are independent
dimensions, although in some cases choosing a larger
internal clearance can allow you to use a tighter
interference fit. Please contact NTN engineering
for details. |
|
| What is back-to-back
and face-to-face in angular contact bearings? |
|
Back-to-back (DB) or face-to-face (DF)
are duplex arrangements of angular contact bearings
(can also refer to taper bearings). Radial loads
and axial loads in either direction can be accommodated
by these arrangements. DB should be selected when
shaft mounting rigidity is the primary factor. Select
DF when shaft misalignment is a concern. The DB
arrangement requires the inner rings to be clamped
whereas the DF arrangement requires the outer rings
to be clamped. |
|
| What is the difference
between angular contact bearings and deep groove
ball bearings? |
|
Deep groove ball bearings are a non-separable
type bearing with the line connecting contact points
of the steel ball and inner ring and the steel ball
and outer ring of 0º in the radial direction. They
are designed to take mainly radial loads but can
handle some axial load in either direction. Angular
contact bearings are a non-separable type. The line
connecting contact points of the steel ball and
inner ring and the steel ball and outer ring create
an angle with the line drawn in the radial direction
called the contact angle. In addition to radial
loads, relatively heavy axial loads in one direction
can be accommodated by an angular contact bearing.
The larger the contact angle, the larger the axial
loading capacity becomes. |
