MINIATURE BEARINGS
Part Numbering System
IMPORTANT NOTE:
The National Precision Bearing numbering system identifies ball bearing size and
design. This system is not a guide to create a customized ball bearing. Please
use the numbering system to decipher the basic bearing numbers listed in the
catalog, or to define a number given to you by a representative of National
Precision Bearing. Please consult a member of the National Precision Bearing
sales or engineering staff to help you design a new bearing or to interchange
another manufacturer's part number.
| MINIATURE BEARINGS | PART NUMBERING SYSTEM | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Example: | SS RI 418 | ZZ H A5 P25 LO2 | ||||||||
| NPB PART NUMBER | ADDITIONAL SPECIFICATIONS | |||||||||
| GROUP 1 | GROUP 2 | GROUP 3 | GROUP 4 | GROUP 5 | GROUP 6 | GROUP 7 | GROUP 8 | GROUP 9 | GROUP 10 | GROUP 11 |
| Material | Type | Basic Size | Seals & Shields |
Modifications | Premium Features |
Cage | ABEC Tolerance |
Radial Play |
Torque | Lubricant |
| SS | RI- | 418 | ZZ |  |
H | A5 | P25 | LO2 | ||
| SS= AISI stainless steel (440C)
No Code= Chrome alloy steel (52100) SE= AISI stainless steel rings (440C) with ceramic balls DD™= NMB 400 Series martensitic stainless steel S= 400 Series martensitic stainless steel (Std. Ref.) DS™= 400 Series high performance stainless steel and 440C balls |
RI, R, L= Radial
RIF, RF, LF= Flanged Radial F= Flanged, Tapered O.D. MBRI, MBR, MBL= Inner ring relieved and separable MBRIF, MBRF, MBLF= Inner ring relieved and separable, flanged outer ring MDRI, MDR, MDL= Inner ring relieved and non-separable MDRIF, MDRF, MDLF= Inner ring relieved and non-separable, flanged outer ring MERI, MER, MEL= Outer ring relieved and non-separable MERIF, MERF, MELF= Outer ring relieved, flanged and non-separable MBF= Inner ring relieved and separable, outer ring flanged and O.D. tapered MDF= Inner ring relieved and non-separable, outer ring flanged and O.D. tapered |
Inch Series First one or two digits indicates O.D. in 16ths of an inch. The following two or three digits indicate the bore size in a fraction of an inch, the first digit being the numerator and the second or the second and third digits being the denominator. Metric Series X= (following basic size) Indicates special internal design, assigned in numerical sequence, i.e. X1, X2, etc. |
Enclosures
Z= Single metallic shield-removable ZZ= Double metallic shield-removable ZO= Single shield on side opposite flange D= Single rubber seal DD= Double rubber seal 2RS= Two rubber seals D1= Single Viton® seal DD1= Double Viton® seal L= Single glass-reinforced PTFE seal LL= Double glass-reinforced PTFE seal LO= Single seal on side opposite flange LZ= Glass reinforced PTFE seal and shield with seal on flange side ZL= Shield and glass reinforced PTFE seal with shield on flange side H= Single metallic shield non-removable HH= Double metallic shield non-removable K= Single metallic shield non-removable KK= Double metallic shield non-removable S= Single rubber seal, non-contact SS= Double rubber seal, non-contact |
Extended Inner Ring
EE= Both sides E= One side
Special External Dimension A_ _ = Larger than standard O.D. A= Semi-standard, larger width and O.D. bearing A_ _ _ _= Larger O.D. than standard and special width W= Wider than standard width Y= Narrower than standard width N= Larger or smaller bore than standard
Special Design SD= Special design bearing |
MC= Premium ball & race finish for specific applications MT= Noiseless motor quality |
CR= Ribbon PTFE coated
F= Full ball complement H= Crown, land piloted J= Crown, acetal KB= Crown phenolic, paper base KC= Crown phenolic, linen base KF= Crown phenolic, linen, non keyhole type, outer land piloting KG= Crown phenolic, paper base, outer land piloted KM= Full type, phenolic, linen base KN= Full type, phenolic, paper base M4= Full type, polyimide M5= Crown, polyimide R= Ribbon, land piloted RD= Ribbon, ball piloted SF= Composite metal polymer retainer "silver" T1= Crown, specialty material |
A1= ABEC 1*
A3= ABEC 3, 3P A5= ABEC 5, 5P, 5T A7= ABEC 7, 7P, 7T A9= ABEC 9, 9P Note: Selected ABEC 9 tolerances are available on all sizes. Please consult NPB. * A1 miniature and instrument bearings of both the metric and inch configurations meet the tolerances of ABMA Standard 20 for ABEC 1 metric series bearings |
P= Followed by two, three, or four numbers indicates the radial play limits in ten thousandths of an inch. Example: P25 indicates radial play of .0002” to .0005”. |
T= Followed by a number that indicates maximum starting torque in hundreds of mg. mm. Example: T15 indicates a maximum starting torque of 1500 mg. mm. RT= Followed by a number that indicates maximum running torque in hundreds of mg. mm. Example: RT15 indicates a maximum running torque of 1500 mg. mm. |
Lubricant letter codes are followed by a number to indicate specific type
BC= Following lubricant code indicates barrier coating LB= Mixture of oil and solvent LD= Dry, no lubricant LF= Dry film LG= Greases LM= Mixture of oil and grease LO= Oils LY= Expanded list of oils and greases Grease Plate Code (follows lubricant code) GPL= Light GPM= Medium GPH= Heavy |
Note:
Radial Load Ratings shown are for 52100 chrome steel.
DD™ is a Trademark of NMB Corporation.
DS™ is a Trademark of the NHBB Corporation.
Viton® is a Registered Trademark of Dupont Corporation.
