Taper, tweak, sketch on an angled box and reorient the Move tool axes to make a bevel gear.
Drafting, Modeling and 3D Printing with Lydia Sloan Cline
Hand drafting for Interior Design, SketchUp, Autodesk 123D and MakerBot
Taper, tweak, sketch on an angled box and reorient the Move tool axes to make a bevel gear.