Linear Bearings Bushings

Linear Bearing + Bushing Selection — Quick Reference

Linear bearings + bushings carry LINEAR motion loads — shaft sliding through bearing for CNC + automation + measuring + positioning + linear actuator applications. Ball bearings + plain bushings + sealed housing units.

Critical: Shaft surface MUST be hardened (HRC 60+) — soft shaft destroyed by bearing balls. Maintain shaft straightness — bent shaft = jammed bearing. Lubricate ball bearings — sealed types need re-greasing per spec; open types need housing lubrication. Brands: SKF, igus. Companion: bearings, spherical bushings, bushings.

Linear Bearings & Bushings — Linear Ball Bearings & Housing Units

Linear bearings and bushings provide low-friction, guided linear motion along precision shafts — the foundation of CNC machine axes, robotic systems, and precision linear motion equipment. AIMS Industrial stocks linear bearings from Samick — closed and open LM series linear ball bearings, and linear bearing housing units for precision and general linear guidance applications.

Linear Bearings & Bushings We Stock

Closed Linear Ball Bearings — LM Series

Samick LM (Linear Motion) series closed linear ball bearings for shafts from 6mm to 80mm — the most common linear bearing for CNC axis guidance, 3D printer carriages, and precision slide systems. Samick LM bearings provide low-friction ball recirculation for smooth, precise linear motion with industry-standard LM series dimensions.

Open Linear Bearings — LMO/LMF Series

Samick open linear bearings allow the bearing to be mounted with shaft access for overhung mounting configurations — used where a closed bearing cannot slide onto the shaft end due to shaft fixtures or machine geometry. Available across the standard LM bore range.

Linear Bearing Housing Units — SC, SH & SB Series

SC (round flanged), SH (square flanged), and SB (open) linear bearing housing units for quick installation on machine beds and frames without precision machining. The self-aligning linear bearing insert accommodates minor shaft misalignment. Compatible with Samick LM series bearings across standard bore sizes.

Linear Bearing Selection Guide

Shaft Tolerance Required

Linear ball bearings require close shaft tolerances — typically h6 for closed bearings (light preload) and g6 for open bearings (no preload). Undersized shafts allow bearing play; oversized shafts bind the bearing. Measure shaft diameter carefully before specification.

Dynamic vs Static Load Rating

Linear bearing load ratings are given as dynamic (Caa, for calculating life under repeated loading cycles) and static (C0a, for occasional or infrequent peak loads). Confirm both ratings against the application load — static rating is the limiting factor for slow-moving, high-load applications.

Bearing Length Selection

• Standard LM series — for general linear motion applications
• Long LML series — increased load capacity and reduced bearing pressure for longer stroke applications
• Adjustable LME/LMEF series — pre-load adjustment for precision applications requiring zero-play guidance

Expert Support: Contact our team or request a quote — we’ll help size and specify the right valve for your pipeline and fluid handling requirements.

As a proudly Australian business since 1988, we stock locally and work with trusted distributors to ensure fast, reliable supply.

See our full bearings range including ball bearings, cam followers, and locking assemblies.

People Also Ask — Linear Bearings and Bushings

Q: What's a linear bearing?

A linear bearing supports linear (straight-line) motion — distinguished from rotational bearings which support rotation. Common types: linear ball bushings (recirculating balls on a hardened shaft), bronze plain bushings (sliding contact, oil-lubricated), self-lubricating polymer bushings (Iglidur-type), and linear guide rails (precision rail with carriage). Used in CNC machines, automation, hydraulic cylinders, machinery, and any application requiring smooth linear motion under load.

Q: Ball bushing or plain bushing?

Ball bushing (recirculating ball linear bearing): low friction, high precision, suitable for high-speed and precision applications. Requires hardened ground shaft. Plain bushing (bronze or polymer): higher friction, lower cost, no maintenance required (polymer types), suitable for low-speed slow-cycle applications. For CNC and automation, ball bushings; for slow-speed adjustment and low-precision linear motion, plain bushings. See [Linear Bearing Guide](/blogs/product-guides/linear-bearing-guide).

Q: What shaft do I use with linear bearings?

Hardened ground shaft for ball bushings — typically 50-62 HRC hardness with smooth ground finish (Ra 0.4 µm or better). Available in chrome-plated carbon steel, stainless steel, or hard-chrome plated steel. Diameter must match the bushing ID (8mm, 10mm, 12mm, 16mm, 20mm, 25mm, 30mm, 40mm, 50mm common). For polymer bushings, shaft hardness requirements are less stringent. Don't use unhardened or rough shaft with ball bushings — fast bushing failure results.

Q: What load can linear bearings handle?

Varies by type and size. Small ball bushings (8-16mm): rated 100-500N typical. Mid-size (20-30mm): rated 500-2000N. Large (50mm+): rated 2000-10000N. Polymer bushings rated higher in continuous static load but lower in dynamic. Manufacturers publish dynamic and static load ratings for each bushing. Apply safety factor 2-3× for shock or impact loading. For heavy-duty industrial linear motion, linear guide rails carry higher loads than bushings on shaft.

Q: Sealed or open linear bearings?

Sealed: rubber end-seals exclude contamination, retain grease — suits dusty environments and outdoor use. Slightly higher friction. Open: lower friction, suitable for clean indoor environments with positive air filtration. Match to operating environment. For automotive, agricultural, and outdoor industrial: sealed. For clean CNC workshops and indoor lab: open. Lubricated for life on sealed types; open types need periodic relubrication.