SC8UU Linear Bearing Slide Block - 8mm for CNC & 3D Printers

Specifications

• Shaft Diameter: 8mm

• Bearing Model: LM8UU (Integrated)

• Housing Material: Anodised Aluminium Alloy

• Mounting Holes: 4 x M4 Tapped Holes

• Dimensions: 34mm (L) x 30mm (W) x 22mm (H)

• Dynamic Load Rating: ~274N

• Static Load Rating: ~392N

• Weight: 52g

• Mounting Pitch: 24mm x 18mm (Center-to-Center)

Key Applications & Projects

• 3D Printers: The industry standard for Y-axis beds (Prusa i3 style) and X-axis carriages.

• Mini CNC Routers: Rigid enough for light engraving and PCB milling machines.

• Camera Sliders: Create smooth, friction-free camera rails for video projects.

• Laboratory Automation: Sample movers and XY stages.

Unlock New Capabilities (Project Evolution)

• Prerequisite: You may be using LM8UU bearings held in place with 3D printed plastic parts.

• The Upgrade: Plastic flexes under heat and stress. Upgrading to SC8UU Aluminum Blocks stiffens your entire machine structure. A stiffer machine means faster print speeds and sharper corners without wobble.

• Effort Level: Beginner. Simply bolt it on.

Virtual Technician: Installation & Maintenance Guide ⚠️

• Alignment is Key: When using 2 or more blocks on a single rail, tighten the screws after sliding them onto the rod. This ensures they align perfectly with the shaft and don't bind.

• Lubrication: Linear bearings come with storage oil, not lubrication grease. For long life and silence, inject White Lithium Grease or Synthetic PTFE Lube into the bearing races before use.

• Rod Quality: These bearings require Hardened & Ground Chrome Plated Rods (h8 tolerance). Do not use soft stainless steel or aluminum rods, as the ball bearings will cut grooves into them.

Package Includes: 1 x SC8UU Linear Bearing Slide Block - 8mm

Specifications

• Shaft Diameter: 8mm

• Bearing Model: LM8UU (Integrated)

• Housing Material: Anodised Aluminium Alloy

• Mounting Holes: 4 x M4 Tapped Holes

• Dimensions: 34mm (L) x 30mm (W) x 22mm (H)

• Dynamic Load Rating: ~274N

• Static Load Rating: ~392N

• Weight: 52g

• Mounting Pitch: 24mm x 18mm (Center-to-Center)

Key Applications & Projects

• 3D Printers: The industry standard for Y-axis beds (Prusa i3 style) and X-axis carriages.

• Mini CNC Routers: Rigid enough for light engraving and PCB milling machines.

• Camera Sliders: Create smooth, friction-free camera rails for video projects.

• Laboratory Automation: Sample movers and XY stages.

Unlock New Capabilities (Project Evolution)

• Prerequisite: You may be using LM8UU bearings held in place with 3D printed plastic parts.

• The Upgrade: Plastic flexes under heat and stress. Upgrading to SC8UU Aluminum Blocks stiffens your entire machine structure. A stiffer machine means faster print speeds and sharper corners without wobble.

• Effort Level: Beginner. Simply bolt it on.

Virtual Technician: Installation & Maintenance Guide ⚠️

• Alignment is Key: When using 2 or more blocks on a single rail, tighten the screws after sliding them onto the rod. This ensures they align perfectly with the shaft and don't bind.

• Lubrication: Linear bearings come with storage oil, not lubrication grease. For long life and silence, inject White Lithium Grease or Synthetic PTFE Lube into the bearing races before use.

• Rod Quality: These bearings require Hardened & Ground Chrome Plated Rods (h8 tolerance). Do not use soft stainless steel or aluminum rods, as the ball bearings will cut grooves into them.

Package Includes: 1 x SC8UU Linear Bearing Slide Block - 8mm

Frequently Asked Questions (FAQ)

1. What size screw fits the holes?

   • The block has 4 holes tapped for M4 screws.

2. Does this come with the bearing inside?

   • Yes, it is a complete unit: Aluminum Block + LM8UU Bearing inside.

3. Is the bearing replaceable?

   • Yes. Remove the two circlips (snap rings) on the ends, and you can push the old bearing out and insert a new one.

4. Can I use this on a threaded rod?

   • No! This is for Smooth Rods only. It will not slide on threaded rods.

5. Why does it sound scratchy?

   • New bearings often sound "scratchy" until they are greased and broken in. Clean the factory oil and apply proper grease.

6. Will this fit my Prusa i3?

   • Most Prusa i3 designs use this block (SC8UU) or the bare bearing (LM8UU). Check your manual.

7. What is the difference between SC8UU and SC8LUU?

   • SC8UU is the standard "Short" version (34mm long). SC8LUU is the "Long" version (58mm long) which has two bearings inside for extra stability.

8. Can I replace the bearing with a plastic bushing?

   • Yes, standard RJ4JP-01-08 plastic bushings fit inside this housing perfectly.

9. Is the aluminum anodized?

   • Yes, usually silver anodized for corrosion resistance.

10. Does it rust?

    • The housing is aluminum (won't rust). The bearing balls are steel (can rust if not greased).

11. How much weight can it hold?

    • Dynamic load is ~27kg. Static load ~39kg. For 3D printing, this is plenty.

12. Is there play/wobble?

    • There should be very minimal play. If it wobbles, your smooth rod might be undersized (under 7.95mm).

13. Can I use this for a laser cutter?

    • Yes, it's very common in diode laser frames.

14. What is the distance between mounting holes?

    • 24mm (Lengthwise) x 18mm (Widthwise).

15. Do I need to clean the rod?

    • Yes, keep the rod dust-free. Dust inside the bearing is the #1 cause of failure.

16. Is it suitable for high speeds?

    • Yes, suitable for typical 3D printing speeds (up to 300mm/s).

17. Can I mount it upside down?

    • Yes, linear bearings work in any orientation.

18. Why are balls falling out?

    • If you remove the bearing from the rod, be careful. If balls fall out, the bearing is damaged and needs replacing.

19. What tool do I need to mount it?

    • An M4 Allen Key (Hex Key).

20. Is this compatible with MGN12 rails?

    • No, this is for round rods. MGN12 is a completely different square rail system.