A fully functional, open-cage miniature differential gearbox engineered to demonstrate true automotive kinematics on an ultra-compact scale.

  In classic full-size metal construction sets, gearboxes tend to be rather bulky assemblies with plenty of room to spare. In the MECHANER system, with our strict 6 mm (1/4") modular hole pitch, packing a working planetary bevel gear train into a compact rigid cage is an exercise in watchmaker precision.
  The entire gearbox measures just 78 mm (3.1") in total axle width, 48 mm (1.9") in cage height, and 54 mm (2.1") in depth. It fits comfortably in the palm of your hand, yet incorporates a complete 4-pinion bevel differential with dual independent output axles running on bronze flanged sleeve bearings.
  The model is built from 36 precision laser-cut sheet metal parts, 8 machined solid brass gears, 14 axle and bearing components, and 72 gold-plated fasteners, bringing the total piece count to 130 pieces.

Kinematics & Mechanics

  When you hold the outer cage stationary and turn the left axle shaft, the planetary bevel pinions rotate on their 2 mm cross-shaft, spinning the right axle shaft in the exact opposite direction in buttery, whisper-quiet motion. When both output axles rotate forward together, the entire cage and crown gear assembly locks and turns as a single unit.
  The input crown bevel gear is designed to mesh directly with our standard M2 drive pinions, making this unit a direct drop-in differential for the rear axle chassis of our upcoming vintage commercial lorry and roadster projects.

Assembly Notes & Builder Tips

  Building the cage requires careful attention to alignment. The 2 mm ground steel shafts must sit perpendicular within 0.05 mm tolerances to ensure the brass teeth mesh without tight spots. We recommend using the included 0.3 mm gold-plated micro-shims between the thrust faces and the bronze bushings to dial in the gear backlash.
  All frame fasteners use our signature 24-karat gold-plated M2 hex bolts and nuts. In addition to creating an exquisite visual contrast against the mirror-polished stainless steel cage, the malleable gold layer prevents thread galling during fine adjustments.
  The parts list ("Rozpiska") diagram in the gallery shows the complete component inventory and quantities required for the build.