Project Overview

On Chile’s mining and construction sites, the Kato NK300 mobile tower crane handles heavy lifts day in, day out. The dry, dusty air and constant shock loads demand a slewing ring that won’t let them down. We delivered a heavy-duty external-gear version that fits OEM standards perfectly and handles continuous rotation without a wobble.

It starts with premium 42CrMo steel. We integrally quench the raceways and gear teeth, then test hardness to DIN Class 7. Our production includes drilling oil holes, assembling inner and outer rings, debugging gear meshing, and precisely measuring clearance. Every finished ring is fully inspected against the technical drawings before packing.

The real value is in the lubrication channels and multi-layer dust seals – they stop fine mine grit from getting inside, extending service life even with over 2,000 annual operating hours. We’ve got photos of every step: heat treatment, machining, assembly testing, and the final waterproof wooden crate. This external-gear ring gives the NK300 stable rotation that Chilean operators can count on.

Technical Highlights

  • Custom triple-lip seal design to prevent dust and moisture ingress
  • Induction-hardened raceway: 55–58 HRC surface, 3.5 mm case depth
  • External gear profile: module m=6, Z=168, 20° pressure angle
  • Load capacity: 680 kN axial, 135 kNm overturning moment
  • Grease refill interval extended from 80h to 200h with polyurea-based high-temp grease
  • Pre-assembly ultrasonic inspection and 360° torque test before shipment

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