I would suggest creating a standard part as the casting and using the
casting to create a derived part that will be the machined part. There are
several advantages to this approach.
First, this approach guarantees that all features in the casting are applied
to the machined part. Second, the casting and machined part are separate
(but linked) files allowing you to easily assign independent part numbers.
Third, this approach resembles the actual process used to produce the
finished part. The casting model (and associated drawing) can be used to
inspect the finished casting. Then, the casting is machined as shown by the
machined model (and associated drawing). Finally, by keeping the casting
and machined features in separate files, cast versus machined features are
By the way, I use this method every time I need to model the machining of a
cast part. It works extremely well and is easily understood by anyone else
that needs to work with the files.
John Eric Voltin
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