Here's a pic of a mold I just finished. Its for lead downrigger weights for a friend who runs a charter boat on Lake Michigan.
The mold is made from 2" thick alum plate. one weight is a 20 pound , the other is 12 pounds. These are used for fishing 200 + feet deep.
I first designed these in solid works to get the correct weights needed , then imported a cad dwg into featurecam to write the code. The main body was all machined with a .500 ball end mill on the y z plane with a .030 step over. No g2 or g3. All g1 moves . The fins were done with a .250 and a .375 ball end mills. Over one million lines of code. Then a little elbow grease. Of course the finish didn't have to be that good , but then I tend to get a little carried away.
Ed