Choosing a replacement bearing for a motor, gearbox, or power transmission assembly usually comes down to one question: is the load pressing across the shaft or pushing along it? The 604ZZ set and the NTA613 set answer that question in completely different ways. The 8 Pcs 604ZZ 4x12x4mm Deep Groove Ball Bearing Metal Sealed Industrial Bearing is a general-purpose ball bearing for rotating equipment, while the High-Capacity 3/8" Bore Thrust Needle Roller Bearings with Washers - 19kN Static is built to carry heavy thrust along the shaft. Match the style to your load direction and the choice becomes straightforward.
The practical step is to match the bearing type to the load path in your assembly. That distinction matters more than the price difference, because each bearing is designed for a different job.
Quick verdict
If your priority is a general-purpose ball bearing set for shop equipment, choose the 604ZZ set. If your priority is a high-capacity thrust bearing with washers, choose the NTA613 set.
Comparison
| Consideration | 8 Pcs 604ZZ 4x12x4mm Deep Groove Ball Bearing Metal Sealed Industrial Bearing | High-Capacity 3/8" Bore Thrust Needle Roller Bearings with Washers - 19kN Static |
|---|---|---|
| Price | $17.75 | $7.99 |
| Bearing style | Deep groove ball bearing | Needle roller thrust bearing |
| Key size | 4mm bore, 12mm outer diameter, 4mm width | 3/8" bore, 13/16" outer diameter, 5/64" thickness |
| What's included | Eight bearings | Bearing with washers |
| Seal / lubrication | Metal sealed | Oil compatible |
Where each product wins
The 604ZZ set wins when you are covering several rotating-shaft positions at once. It fits miniature gearboxes, small motors, power tools, and household appliances. The NTA613 wins when the load is axial. With a 19kN static rating, a 7.75kN dynamic rating, and a 15,000 RPM maximum, it is built for high thrust in a small envelope.
Product notes
8 Pcs 604ZZ 4x12x4mm Deep Groove Ball Bearing Metal Sealed Industrial Bearing
If you are restocking spare bearings for several small machines, this Uxcell set gives you eight 604ZZ bearings in one order for $17.75. The deep groove ball bearing design suits miniature gearboxes, small motors, power tools, and household appliances, and the metal seals are a practical fit for fans, printers, and mixers that collect dust. Each bearing uses a 4mm inner diameter, 12mm outer diameter, and 4mm width, so it will only fit positions that match that exact metric size. As a full eight-pack, it makes sense when you have multiple replacement points; if you only need one bearing for a single repair, you will be buying more pieces than the job requires.
High-Capacity 3/8" Bore Thrust Needle Roller Bearings with Washers - 19kN Static
When your assembly is carrying an axial load, this NTA613 thrust bearing set is the more specialized option. It uses chromium steel rollers, a ST13 steel cage, and 65Mn spring steel washers, and it is rated for 19kN static and 7.75kN dynamic loads. The 3/8" bore and 13/16" outer diameter keep the package compact, while the 15,000 RPM rating and oil-compatible design point to high-speed thrust applications. The trade-off is that you are getting one bearing set rather than eight separate bearings, so it is not a multi-point replacement pack. For a single heavy axial load position, it gives you a load orientation purpose-built for that application.
Final choice by use case
For a workshop restock of small ball bearings, choose the 604ZZ set. For a compact high-capacity thrust bearing with washers, choose the NTA613 set. The deciding factor should always be the direction of the load in your power transmission setup.
