That minimum order is significantly higher than the price of the part from Germany... even with shipping. And with the gear, one spare isn't that useful... and the parts for the trike ( http://www.terratrike.com/tandem.php ) tend to be a bit specialized - I don't know anyone else who has one (mine is similar though has different parts and such because its a folding http://www.terratrike.com/traveler.php ). In the past, my father has gone to the machine shop where he used to work for custom parts - but the people who he had favors with to get some time for non-academic projects have nearly all retired.

Yes, it is certainly cheaper to have an industrial cutter if you know what you're making and making them in lots that cost a few hundred dollars. If you are after making a part rather than a half dozen... that minimum order and turn around time (do it on Saturday, have it on Sunday?) make it less interesting for some applications.