Do you mind letting me know why you are against publishing cad files of your design? It's so odd to me. Your design is not unique, even the only relatively complex part (belt tensioner) is not your own original design.
Are that worried about your design being too easily remixed? What? Why would you want to make it harder for people to improve on your design????
Especially considering you put the open source logo on there in the first place, and then you go against everything open source stands for. Makes no sense to me. An explanation would be appreciated. Thanks.