Linear shaft

The choice of material directly impacts the shaft's lifespan and performance. For standard industrial use, GCr15 (High Carbon Chromium Bearing Steel) is the most common due to its excellent balance of hardness and wear resistance. If your application involves corrosive environments, such as food processing or chemical plants, you must specify SUS440C stainless steel or SUS304. Ensure the surface hardness reaches HRC60-64 for carbon steel to prevent premature grooving from ball bearing contact.

Precision is critical in linear motion. Most high-quality linear shafts should adhere to a g6 or h6 tolerance class to ensure a proper fit with linear bushings. The surface roughness should be maintained at Ra 0.8μm or lower; a smoother finish reduces friction, minimizes noise, and significantly extends the life of the bearings. Always request a straightness measurement, typically required to be within 0.1mm per 1000mm.

A professional supplier must provide Induction Hardening. This process creates a hardened outer layer (usually 1.5mm to 3mm deep) while maintaining a tough, flexible core that can absorb shocks without snapping. Verify the effective hardened layer depth in the technical data sheet, as insufficient depth will lead to surface collapse under heavy loads.

Yes, B2B buyers should look for suppliers capable of CNC machining services. Common customizations include axial or radial tapped holes, reduced diameters (steps), keyways, and snap-ring grooves. Providing a detailed CAD drawing is the best way to ensure accuracy and reduce the risk of receiving unusable stock.

Linear shafts are highly susceptible to oxidation. You must mandate that the supplier applies a heavy coat of anti-rust oil and uses VCI (Vapor Corrosion Inhibitor) plastic wrapping. For bulk shipments, ensure the shafts are packed in reinforced wooden crates with internal supports to prevent bending or surface scratches during transit.

Prioritize Audited Suppliers on Made-in-China.com who have undergone third-party inspections by SGS or TÜV Rheinland. Check their Audit Reports specifically for 'Production Capacity' and 'Quality Control' sections. Requesting a material mill test certificate (MTC) before the balance payment is a standard industry practice to ensure the steel grade matches your order.

Focus on the price per meter and the machining cost per end. For orders exceeding 500 pieces, you can typically negotiate a 10-20% discount. To secure the best rates, consider a blanket order where you commit to a yearly volume but ship in smaller monthly batches, which helps the manufacturer optimize their raw material purchasing.

The primary risk is structural bending. Shafts exceeding 2 meters require specialized handling. Ensure the Incoterms are clearly defined; FOB (Free On Board) is recommended for experienced buyers to maintain control over the logistics provider. Always include shipping insurance that specifically covers 'physical deformation' and 'water damage'.