12-Tooth Spur Gear, Corrected R3.550 Root

Repair the attached STEP model of my 12-tooth spur gear. **CRITICAL PROBLEM:** The existing tooth-root geometry is incorrect. The actual minimum root diameter is approximately Ø6.589 mm, but the required root diameter is exactly Ø7.100 mm. **REQUIRED GEOMETRIC CORRECTION:** 1. Establish a concentric root circle with an exact radius of 3.550 mm (diameter Ø7.100 mm). 2. Reconstruct all 12 tooth-root regions so that their minimum radial distance from the gear's central axis is exactly 3.550 mm. 3. No point on the external tooth profile, including the root fillets and flank transitions, may extend radially inward below 3.550 mm. 4. Every tooth valley must reach the 3.550 mm root circle, with smooth transitions to the adjacent tooth flanks. 5. Preserve the existing involute tooth flanks above the corrected root transitions, including tooth thickness, angular spacing, and tip geometry. 6. Do not create inward-dipping splines, undercuts, or fillets that cross inside the 3.550 mm root circle. **PRESERVE THESE EXACT DIMENSIONS:** - Number of teeth: 12 - Module: 0.75 mm - Pressure angle: 20° - Pitch diameter: Ø9.000 mm - Outside diameter: Ø10.500 mm - Root diameter: Ø7.100 mm - Gear face width: 7.530 mm - Hub outside diameter: Ø9.000 mm - Hub extension: 4.470 mm - Overall length: 12.000 mm - Central axial through-bore: Ø5.000 mm - Transverse through-hole: Ø2.300 mm - Transverse hole center: Z = 8.780 mm - Gear/hub shoulder: Z = 7.530 mm - Nominal shoulder-to-hole-edge clearance: 0.100 mm The transverse hole must remain perpendicular to the gear axis, intersect the central bore, and align beneath two opposite tooth valleys. **CONSTRUCTION REQUIREMENTS:** Use a mathematically defined root circle of radius 3.550 mm. Construct the 12 tooth profiles outside this circle. Trim or replace the incorrect root transitions. Avoid modifying the existing tooth tips, involute flanks, bore, hub, and transverse hole. If local geometry repair fails, reconstruct the complete gear from the specified dimensions rather than retaining the incorrect root geometry. **MANDATORY VALIDATION:** Before exporting: - Verify all 12 tooth valleys reach exactly radius 3.550 mm. - Verify no external tooth-root boundary has a radius below 3.550 mm. - Check the root diameter at Z = 0.5, 3.0, and 7.0 mm. - Confirm the outside diameter remains Ø10.500 mm. - Confirm the transverse hole is Ø2.300 mm and centered at Z = 8.780 mm. - Confirm the solid is watertight, valid, and contains no self-intersections. Export one valid STEP solid in millimeters. Do not rescale the model.

Parameters

Every value above is a live dimension. Open a model like this in the editor and each one becomes a slider you can drag before exporting.