12mm x 400mm Linear Motion Rod Shaft Guide Chrome Plated and Case Hardened for 3D Printers CNC DIY Projects With Metric H8 Tolerance, 2 Pieces For Precise, Smooth Motion In Heavy Duty Builds

12mm x 400mm Linear Rail Shaft Pair for CNC & 3D Printers
✔️ 2-piece chrome-plated, H8 tolerance, HRC58-64, ends chamfered

These 12mm x 400mm linear rail shafts provide precise guidance for heavy-duty motion in CNC machines, 3D printers, and automated equipment. Sold as a pair to support paired axis drives.

✅ Diameter x length: 12 mm x 400 mm
✅ Material: carbon steel C45#
✅ Hardness: 58-64 HRC (case hardened)
✅ Chrome thickness: 15-20 μm
✅ Surface roughness: Ra 0.8-1.6
✅ Tolerance: H8
✅ Straightness: ≤5 μm/100 mm
✅ Chamfered ends on both sides
✅ Pack: 2 pieces

💡 What is a 12 mm x 400 mm linear rail shaft used for in CNC and 3D printer setups? This handy guide explains what these rails do and why they matter.

- Handy for guiding moving components in CNC machines and 3D printers - Delivers smooth motion with hardened steel and chrome plating for durability - Maintains tight tolerances to ensure repeatable positioning under load - Widely used in DIY CNC, milling, and 3D printer projects ✝️