I'm working on a project where parts will snap together, alot like Lego blocks. Does anyone know what tolerances I should use between the male and female parts? The 'snap' should resemble a lego 'snap'.
If it were my problem I wouldn't try to duplicate the Lego block snap together design because Shapeways' 3D printing machines don't have the repeatability nor precision necessary to make it work well. There is one 3D printing service bureau that I know of that does have this capability, but you'd be paying about $80 US per block.
What I would do is come up with a snap design that doesn't require ultra high precision and ultra high repeatability. Something like what you'd find on ordinary clothing for example. For tolerances, we would need to know what material you would like to use and we would need to know more about the application as well.