Need help designing an interlock between two 3D printed components

[fred_dot_u]

If you want to toss the test portions of the models at me, I can print them to check your clearance before you pay the big bucks to have them printed. If you're in the USA, I'd be willing to print your final model as well for a far lower price than the big operations would charge. What program do you use for your modeling?

[JeffZ]

Hi Fred, that's very generous of you!! I may take you up on that. Currently i'm using tinkercad online to design my models, but i'm open to other suggestions.