# NTN 51208 Thrust Ball Bearing - 40 mm Bore, Single Direction, Straight Bore - MROSupply.com

***NTN 51208 single direction thrust ball bearing with 40 mm straight bore. Separable shaft and housing washer design for easy mounting. Handles axial loads in one direction for vertical shaft applications in machine tools, gearboxes, and industrial machinery.***



## Product details:

- Catalog number: 51208
- SKU: 283296
- Price: ***$69.24*** Each
- Shipping: ***FREE SHIPPING***  ON ORDERS OVER $100
- Typically Ships in: 1 day
- Brand: [NTN Bearing](https://www.mrosupply.com/brands/ntn-bearing/)
- Category: 
    - [Ball Thrust Bearings](htts://www.mrosupply.com/bearings/ball-bearings/ball-thrust-bearings/)
    - [Ball Bearings](htts://www.mrosupply.com/bearings/ball-bearings/)
    - [Bearings](htts://www.mrosupply.com/bearings/)
- Unit of measure: each
- Weight: 0.569 lb


## Product images:
- https://static.mrosupply.com/images/noimage.webp


## Product attributes;

  
- Ball Material: Steel
  

  
- Ball material: Steel
  

  
- Bore Type: Round
  

  
- Bore type: Round
  

  
- Cage Material: Steel
  

  
- Cage material: Steel
  

  
- Cage Type: Pressed
  

  
- Cage type: Pressed
  

  
- Configuration: One
  

  
- D (in): 2.6772
  

  
- d (in): 1.5748
  

  
- D1: 1.6535 in
  

  
- d1: 2.6772 in
  

  
- Da max: 2.2441 in
  

  
- da min: 2.2441 in
  

  
- Dynamic Load Rating: 10600 lbf
  

  
- Dynamic load rating: 10600 lbf
  

  
- Enclosure: Open
  

  
- I.D.: 40 mm
  

  
- Limiting Speed - Grease: 2700 RPM
  

  
- Limiting speed - grease: 2700 RPM
  

  
- Limiting Speed - Oil: 3900 RPM
  

  
- Limiting speed - oil: 3900 RPM
  

  
- Material: High carbon chrome steel
  

  
- O.D.: 68 mm
  

  
- Operating Temperature Range: -40 to 250 °F
  

  
- Operating temperature range: -40 to 250 ºF
  

  
- Outside Ring Type: Straight
  

  
- Precision: ISO class 0
  

  
- r (in): 0.0394
  

  
- Radial Internal Clearance: CN
  

  
- Radial internal clearance: CN
  

  
- ras max: 0.0394 in
  

  
- Seal material: None
  

  
- Seal type: None
  

  
- Static Load Rating: 22100 lbf
  

  
- Static load rating: 22100 lbf
  

  
- T (in): 0.7480
  

  
- Type: Thrust Ball Bearing
  
## Product documents / software:

- [Drawing](https://documents.mrosupply.com/product_documents/50/48/5048886/1264_S_mICK0xq.png)
## Alternate products to `NTN 51208 Thrust Ball Bearing - 40 mm Bore, Single Direction, Straight Bore - MROSupply.com`:
- [SKF 51208 is a 40mm bore thrust ball bearing with a sheet metal cage. Designed for axial loads in one direction, it accommodates moderate speeds and is suitable for machine tool spindles, clutches, and general industrial applications.](https://www.mrosupply.com/products/320536/as-markdown/)
- [NSK 51208 thrust ball bearing with 40 mm bore and pressed steel cage. Designed for pure axial loads in vertical-shaft applications. Backed by NSK's precision-bearing engineering heritage.](https://www.mrosupply.com/products/5032836/as-markdown/)
- [Rollway 51208 BALL THRUST 51100-51400](https://www.mrosupply.com/products/2302294/as-markdown/)
- [FAG 51208 single direction thrust ball bearing, 40mm bore, 68mm OD. Designed for axial loads in one direction, suitable for moderate-speed applications. Manufactured by Schaeffler, meets ISO precision standards for industrial machinery.](https://www.mrosupply.com/products/2171512/as-markdown/)






## FAQ:

- How do I choose the right type of bearing for my application?: Start with the load and how it’s applied. You need to know if you’re dealing with radial loads, axial loads, or a mix of both. Then look at speed, operating environment, and space constraints.
For example, ball bearings are great for high speed and lighter loads, while roller bearings handle heavier loads but usually at lower speeds. If there’s contamination, moisture, or heat involved, you may need sealed bearings or specific materials.
In most cases, the right choice comes down to matching load type, speed, and environment to the bearing design.


- What is the difference between deep groove and angular contact ball bearings?: Deep groove ball bearings are the most common type. They’re designed to handle mainly radial loads, but they can also take some axial load in both directions. They’re simple, versatile, and used in everything from motors to conveyors.
Angular contact ball bearings are built for combined loads, especially where there’s significant axial force in one direction. They’re often used in pairs and are common in higher precision or higher load applications like pumps and gearboxes.
If your load is mostly radial, go deep groove. If axial load matters more, angular contact is usually the better choice.