{"id": "card_n_f1e483b64f08", "kind": "note", "title": "Build a Soap-Box Car", "body": "Four wheels, a plank, a steering rope, two parents — the classic American gravity racer. Heir to the Soap Box Derby.", "source": {"label": "Popular Mechanics, 1936–38 (verify per issue); Boys' Life", "url": "/maker.html#build-a-soap-box-car", "ref": "Popular Mechanics, 1936–38 (verify per issue); Boys' Life", "authority_tier": "external_aligned"}, "shelf": "maker", "box": "woodworking", "bands": ["A plank of pine, ~4 feet × 1 foot × 1 inch", "Four wheels (lawnmower wheels work; or repurpose old skateboard / wagon wheels)", "Axles (¾-inch dowel rod, or threaded steel rod)", "Eye bolts for the steering pivots", "A length of rope for steering", "Wood screws, paint"], "connections": [{"to_card_id": "card_n_23056c195769", "relationship": "same_section", "origin": "nesting_2026_06_12"}], "author": "engine", "created_at": "2026-05-19T00:00:00Z", "visibility": "public", "lifecycle_stage": "public", "volatility": "permanent", "metrics": {"paperclips_count": 0, "helpful_count": 0, "not_helpful_count": 0, "cite_count": 0, "walks_through_count": 0, "flagged_count": 0, "trust_weighted_score": 0.0}, "updated_at": "2026-05-19T11:52:46.114404+00:00", "source_hash": "bc49652a02514c0c6fd4e57132ed4d216b40f2b6dc9d882c395017ee99040526", "witnesses": [{"class": "self", "label": "Popular Mechanics, 1936–38 (verify per issue); Boys' Life", "ref": "Popular Mechanics, 1936–38 (verify per issue); Boys' Life", "url": "/maker.html#build-a-soap-box-car"}], "witness_status": "self_only", "witness_status_reason": "no registry entry matched \"Popular Mechanics, 1936–38 (verify per issue); Boys' Life\"; only the source itself attests", "surface": "secular"}