89ca9f84-74b4-4baa-8015-fe3c568efbb8

**Geometry:** - Type: Spur gear (involute tooth profile) - Number of teeth: 35 - Outer diameter (including teeth): 65 mm - Gear body thickness: 10 mm - Hub: Integrated, on one side. Hub protrusion: 5 mm from the gear body. Hub diameter: 20 mm. **Critical Dimensions:** - Central hole: Hexagonal (6-sided), sized to perfectly fit a standard 12 mm wrench (across flats dimension: 12 mm). Ensure a slight tolerance for 3D printing. - The hexagonal hole must go through the entire gear and hub (total thickness: 15 mm). **Design Notes:** - The gear must be designed for 3D printing (manifold, no non-manifold edges). - The tooth profile should be a standard 20-degree pressure angle involute form for smooth operation. - Calculate the module based on the outer diameter and tooth count for accuracy. - Ensure the hub is concentric with the gear and has filleted edges where it meets the gear body for strength. - The model should be solid, watertight, and ready for slicing.