Fillet (mechanics)

In mechanical engineering, a fillet (pronounced /ˈfɪlɪt/, like "fill it") is a rounding of an interior or exterior corner of a part.

An interior or exterior corner, with an angle or type of bevel, is called a "chamfer".

Depending on a geometric modelling kernel different CAD software products may provide different fillet functionality.

Usually fillets can be quickly designed onto parts using 3D solid modeling engineering by picking edges of interest and invoking the function.

Once these features are included in the CAD design of a part, they are often manufactured automatically using computer-numerical control.

Example of a non-filleted pole (left) and a filleted pole (right)
It is common to find a fillet where two parts are welded together