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Availability:
31 in stock
Super-precision angular contact ball bearing, 30 x 72 x 19 mm, straight bore, open, machined phenolic cage, ABEC 7/9 (P4S) spindle-grade 300WI series.
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$189.07
31 in stock
31 in stock
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| MFR / Brand | Fafnir |
|---|---|
| MPN | MM306WI2 |
| Model | MM 306 WI 2 CR |
| Bearing Type | Super-Precision Angular Contact Ball Bearing (spindle), Open, both faces |
| ID | 30 mm |
| OD | 72 mm |
| Width | 19 mm |
| Condition | New |
|---|---|
| Base Number | 306 |
| Industry Terms | Spindle bearing; super precision bearing; machine tool bearing; 300WI series; phenolic cage bearing |
| Common Misspellings | MM306W1-2; MM3O6WI-2; MM 306WI 2 |
| Bore Shaft Size | 30 mm |
| Mpn Variants | MM306WI-2; MM306WI2; MM-306-WI-2-CR; MM 306 WI 2 CR; MM306WI; MM306WICR |
| Manufacturer Status | Fafnir super-precision line, now Timken |
| Precision Class | P4S (ABEC 7/9) |
| Material | Chrome bearing steel |
| Cage Type | CR - machined phenolic, outer-land riding |
| Precision Rating | P4S (ABEC 7/9) |
| Series | Fafnir 300WI spindle series (ISO 03 heavy dimension series) |
| Cage Material | Phenolic (fabric-base laminate) |
| Number Of Rows | 1 |
| Bore Type | Straight |
| Snap Ring Included | No |
| Harmonization Code | 8482.10.50.28 |
| Bearing Material | Chrome bearing steel |
| Cross Reference 1 | 2MM306WI (related size, 15 degree contact angle) |
|---|---|
| Cross Reference 2 | 3MM306WI (related size, 25 degree contact angle) |
| Cross Reference 3 | 2MM306WICRDUM (related, matched duplex set) |
| Cross Reference 4 | MM306WI-2 (the -2 suffix is retained as a searchable carton marking) |
Fafnir MM306WI-2 super-precision angular contact ball bearing, 30 mm bore, 72 mm outside diameter, 19 mm width. Straight bore, open on both faces, chrome steel rings and balls with a machined phenolic cage. Timken catalogues the 300WI series as spindle angular contact ball bearings alongside the 9100WI, 9300WI and 200WI families.
MM is Timken’s super-precision spindle prefix and carries the P4S precision class, ABEC 7/9. 306 gives bore code 06 for the 30 mm bore in the 300WI heavy dimension series. WI is the series designation. CR is the machined phenolic outer-land-riding cage.
An angular contact ball bearing takes combined radial and axial load along a contact line inclined to the bearing axis, so it supports a spindle in one thrust direction and is normally mounted against a second bearing to locate the shaft both ways. P4S holds running accuracy tighter than P4 on the critical raceway and face tolerances, which is what keeps spindle runout low at speed. The machined phenolic cage is light, self-lubricating and low friction, and suits oil, oil-air or light grease lubrication in a 72 mm envelope.
Straight cylindrical bore, mounted on an interference fit shaft seat with the outer ring located in a bored housing.
The 30 x 72 x 19 mm envelope corresponds to the ISO 306 heavy series. A 2MM306WI in the same envelope is the 15° execution and a 3MM306WI the 25° execution, making both related sizes rather than interchanges, since the contact angle changes how thrust and speed are balanced.
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