698Z Miniature Radial Ball Bearing - 8x19x6mm Slim Profile Metal Shielded

Specifications

• Model Designation: 698Z

• Bearing Type: Deep Groove Radial Ball Bearing

• Inner Diameter (Bore): 8mm

• Outer Diameter: 19mm

• Width (Thickness): 6mm

• Shield Type: Z (Metal Shielded)

• Material: Bearing Steel

• Lubrication: Pre-lubricated (Grease)

Key Applications and Projects

• Compact Robotic Joints: Providing the smooth pivot points for high-torque robotic arms where an 8mm shoulder bolt is required, but a standard 22mm housing would be too bulky.

• RC Helicopters & Cars: Acting as lightweight, high-RPM main shaft bearings or gearbox supports in hobby-grade remote control vehicles.

• 3D Printer Leadscrew Constraints: Press-fitting into a slim top-bracket to securely constrain the wobble of an 8mm Z-axis trapezoidal leadscrew.

• Power Tool Repair: Serving as replacement armature bearings for small electric drills, grinders, and rotary tools.

Unlock New Capabilities (Project Evolution)

• The High-Torque Miniature Winch: Evolve your heavy-lifting projects! If you need to build a motorized winch for an RC crawler, you need a strong 8mm spool shaft, but you don't have the space for massive bearings. By utilizing two 698Z bearings pressed into a custom, slim 3D-printed chassis, you can support a heavy 8mm steel spool perfectly. This allows an attached high-torque DC gear motor to pull massive payloads without the spool bending or the bearings causing friction, all within an incredibly tiny footprint!

Package Includes:

• 1 x 698Z Radial Ball Bearing (8x19x6mm)

FREQUENTLY ASKED QUESTIONS (FAQ)

1. What does "698Z" mean? "6" signifies a deep groove ball bearing. "9" denotes the dimensional series (very thin section). "8" indicates an 8mm bore size. "Z" means it has a metal shield.

2. What is the inner diameter (bore) size? The inner hole is exactly 8mm in diameter, perfect for 8mm smooth rods or M8 bolts.

3. What is the outer diameter? The outer ring is 19mm in diameter.

4. How thick is this bearing? The standard width/thickness for the 698 series is 6mm.

5. How is this different from a 608 bearing? A 608 bearing (like those in skateboards) has the same 8mm bore, but is much bulkier with a 22mm outer diameter and 7mm width. The 698Z is a space-saving alternative.

6. Do I need to grease or oil these? No, the metal shields signify that the bearing is packed with grease at the factory and permanently sealed for a maintenance-free lifespan.

7. What is the difference between Z and ZZ? "Z" technically indicates a single metal shield on one side, while "ZZ" indicates shields on both sides. Many generic manufacturers use them interchangeably. If your bearing has shields on both sides, it acts as a ZZ.

8. Are these bearings waterproof? No. While the metal shields keep out dust and debris, water can easily seep past the tiny gaps and rust the internal steel balls.

9. Can I use this for axial (thrust) loads? Deep groove ball bearings are designed primarily for radial loads (forces perpendicular to the shaft). They can handle very light axial loads, but heavy pushing parallel to the shaft will cause premature wear.

10. Can I remove the metal shields? Yes, you can carefully pry them out with a needle if you need an open bearing to flush it with a different, thinner lubricant, but you cannot easily reinstall them once bent.

11. How do I properly press-fit this bearing into a housing? When pressing the bearing into a 19mm hole (like a 3D printed part), only apply pressure to the outer metal ring. Pushing on the inner ring will crush the balls against the raceway.

12. How do I press it onto an 8mm shaft? When sliding it over a tight 8mm shaft, only apply pressure to the inner ring.

13. Why does my bearing feel "gritty" when I spin it? Grittiness usually means dirt has bypassed the shields, or the bearing was damaged during a poorly executed press-fit installation. It should be replaced.

14. Is this bearing magnetic? Yes, standard high-carbon bearing steel is magnetic.

15. What RPM can this handle? Due to its small diameter and non-contact metal shields, the 698Z can comfortably handle speeds exceeding 35,000 RPM under appropriate light loads.

16. How much weight can a single 698Z bearing support? The static load rating is roughly 1,100 Newtons (approx. 112 kg / 247 lbs), but for dynamic (moving) longevity, it is best to keep continuous loads much lower.

17. Can I clean these bearings in an ultrasonic cleaner? Doing so will strip out the factory-applied internal grease. Because you cannot easily remove the shields to repack thick grease, ultrasonic cleaning is not recommended unless you specifically want to run them "dry" (which drastically reduces lifespan).

18. What is the maximum operating temperature? Standard bearing steel and grease can typically withstand continuous temperatures up to roughly 120°C (248°F).

19. Do these bearings have a "break-in" period? Yes. Brand-new bearings packed with fresh grease can sometimes feel slightly stiff. Running them under a light mechanical load for a short period distributes the grease evenly for maximum smoothness.

20. Can I use this to stabilize the top of my 3D printer's Z-axis? Yes! It is an excellent choice for a top-mount Z-axis stabilizer because it fits an 8mm lead screw perfectly but requires a much smaller 3D-printed housing than a standard 608 bearing would.