Chamfers, rounds, fillets, and “break edges” are edge features that you may commonly see on your part drawings. They are used for a variety of reasons, which typically include: part strength, burr removal, ease of assembly, and aesthetics.



A round is a rounded external edge feature. A round is shown on the part in Figure 1.

Figure 1: Part with Rounded Edge


A round is indicated on a drawing using Radius. It is dimensioned by including the Radius symbol and radius length, as shown below in Figure 2.

Figure 2: Round Dimensioning



Like a round, a fillet is a rounded edge feature. However, where a round is applied to an external edge, a fillet is applied to an internal edge, as shown in Figure 3.

Figure 3: Part with Filleted Edge


A fillet is indicated on a drawing in the same way as a round, illustrated in Figure 2, with a dimension that includes the Radius symbol and radius length.


Learn more about fillets and rounds in the video below:

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