feat: SaltyTank tracked chassis — drive sprockets, tensioners, skid plate (#121)
Three new chassis design files for the SaltyTank continuous-track variant:
• saltytank_chassis.scad — Deck plate (500×360×8mm Al, DXF export), 2×
side track frames (6mm Al, CNC/laser), idler tensioner sliding block,
4× CSI corner camera mounts (45°/20°), D435i front bracket (8° tilt),
stem collar (Ø25mm shared). Drive sprocket mounts accept hoverboard hub
motors with caliper-verified D-cut bore (16.11mm/13mm flat) + 52mm BC
hub flange bolt pattern. M6 tensioner bolt adjusts idler ±15mm for
track tension. Shared FC 30.5×30.5mm + Jetson 58×49mm M3 patterns.
Electronics bay footprint matches rover_electronics_bay.scad exactly.
• saltytank_skid_plate.scad — Sacrificial underside skid panel (360×500mm).
4mm HDPE (DXF) or PETG print; countersunk M4 FHCS bolt-on. 4× drain/
inspection slots; optional printed ribs (RIB_PRINT=true). Ground
clearance of hull between tracks: 90mm (exceeds 50mm requirement).
• saltytank_BOM.md — Full BOM: deck plate, side frames, drive sprockets,
idler wheels + tensioners, road wheels (2/side), track belts (1109mm
circumference calc), skid plate, sensor brackets, electronics bay
(rover_electronics_bay.scad reused unchanged). Frame mass ≈ 2.98 kg
(just under 3 kg target). Assembly sequence and track tensioning
procedure included.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
sl-mechanical
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