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When your CNC router, 3D printer, or linear actuator demands repeatable, low-friction travel, even a marginal bearing can introduce backlash, vibration, and premature wear that derails your entire build. Engineers, makers, and automation integrators who rely on shaft-guided linear motion need a bearing that holds tight tolerances across thousands of cycles — without constant adjustment or replacement.
These LM-series linear motion ball bearings feature a hardened steel outer shell with recirculating ball retainer and a precision-ground bore. Available in bore diameters from 3 mm (0.118 in) to 50 mm (1.969 in) and corresponding outer diameters from 7 mm (0.276 in) to 80 mm (3.150 in), with body lengths ranging from 10 mm (0.394 in) to 100 mm (3.937 in). The UU suffix denotes double-lip rubber seals on both ends for contamination resistance.
Typical applications include: linear guide rails on desktop CNC routers and laser cutters where smooth X/Y axis travel is critical; 3D printer carriage and bed assemblies requiring low-friction, repeatable positioning; and industrial linear actuator systems, pick-and-place robots, and drawer slide mechanisms where compact bore-to-OD ratios save space without sacrificing load capacity.
Multiple rows of recirculating steel balls distribute radial load evenly across the shaft, delivering smooth, consistent linear travel with minimal stick-slip.
Both ends are sealed with double-lip rubber contact seals that block dust, swarf, and light moisture ingress — extending service life in workshop and light-industrial environments.
Bore diameters from 3 mm to 50 mm (0.118 in – 1.969 in) cover the full spectrum from compact 3D printer carriages to heavy-duty linear actuators — one product family for your entire project.
The outer shell is manufactured from hardened steel, providing the structural rigidity needed to resist deformation under dynamic radial loads during continuous reciprocating motion.
Ball-contact geometry minimises rolling resistance, allowing carriages and slides to start and stop with minimal drive force — ideal for stepper-motor-driven axes where torque budget is tight.
Available in packs of 1, 2, or 4 per order so you can stock exactly what your build requires — whether prototyping a single axis or outfitting a multi-axis machine.
| Bearing Series | LM3 / LM4 / LM5 / LM6 / LM8 / LM10 / LM12 / LM13 / LM16 / LM20 / LM25 / LM30 / LM35 / LM40 / LM50 |
|---|---|
| Type | UU (Double-Lip Sealed) |
| Inner Diameter (ID) | 3 mm – 50 mm (0.118 in – 1.969 in) — See variant options |
| Outer Diameter (OD) | 7 mm – 80 mm (0.276 in – 3.150 in) — See variant options |
| Body Length (L) | 10 mm – 100 mm (0.394 in – 3.937 in) — See variant options |
| Outer Race Material | Hardened Steel |
| Ball Material | Steel (recirculating) |
| Seal Type | Double-lip rubber contact seal (both ends) |
| Motion Type | Linear (reciprocating) |
| Compatible Shaft Type | Hardened, ground round linear shaft (LM-series) |
| Pack Quantity Options | 1 pc / 2 pcs / 4 pcs |
| Dynamic Load Rating | See variant options |
| Static Load Rating | See variant options |
Match the bearing's inner diameter (ID) to your linear shaft diameter. For example, if your shaft is 8 mm, select LM8 (8×15×24 mm). Then confirm that your housing bore matches the bearing's outer diameter (OD) and that the body length (L) fits within your carriage block depth. All three dimensions — ID, OD, and L — are listed in the variant name in the format ID×OD×L mm.
Dynamic and static load ratings vary by size — larger bore bearings carry significantly higher loads. As a general guide, smaller sizes (LM3–LM8) are suited to light-duty applications such as 3D printer axes and small CNC routers, while mid-range sizes (LM10–LM20) handle moderate loads in laser cutters and pick-and-place systems. Larger sizes (LM25–LM50) are appropriate for heavier industrial linear actuators. Contact us to confirm specific load ratings for your application.
The outer race and balls are manufactured from hardened steel, which provides good wear resistance but is not inherently stainless. The double-lip rubber seals (UU type) help exclude moisture and contaminants, extending service life in dusty or lightly humid workshop environments. For applications exposed to water, coolant, or corrosive atmospheres, consider pairing with a compatible lubricant or contact us about alternative seal options.
LM-series linear bearings are designed for use with hardened, precision-ground round linear shafts of the corresponding diameter. Using an unhardened or rough-finished shaft will accelerate ball and raceway wear and reduce bearing life. Ensure your shaft surface hardness is typically HRC 58–64 and surface roughness Ra ≤ 0.4 µm for optimal performance.
LM-series bearings are typically supplied with a light factory grease. For best results, apply a thin film of lithium-based grease or light machine oil to the shaft before installation, and re-lubricate periodically depending on duty cycle and environment. The UU double-lip seals help retain lubricant inside the bearing, reducing re-lubrication frequency compared to open-type bearings.
Yes — LM-series linear bearings are one of the most widely used bearing types in desktop 3D printers (e.g., Prusa, Ender, and similar cartesian-style machines) and small CNC routers. Common sizes for 3D printers include LM8 (8 mm shaft) for X/Y/Z axes. For CNC routers, LM12, LM16, and LM20 are frequently used depending on the machine's shaft diameter. Select the size that matches your existing shaft or linear rail system.
Standard LM-series bearings follow the JIS B 1559 dimensional standard, which is the most common format used in 3D printers and CNC equipment worldwide. LME-series bearings follow the European (ISO) standard and have different outer diameter and length dimensions for the same bore size. Always verify the OD and L dimensions against your housing drawing before ordering to ensure interchangeability.
Most cartesian 3D printers use 6–12 linear bearings depending on axis configuration (typically 2 per rod, with 2–3 rods per axis). A standard CoreXY printer may use 4–6 LM8 bearings for the XY gantry plus 2–4 for the Z axis. CNC routers vary widely. We offer packs of 1, 2, or 4 — order the pack size that matches your build quantity to minimise per-unit cost.
