Well, first of all thanks to all of you for joining in for this conversation
I guess I just touched an interesting area!
I tried to measure 2 different earrings of my wires. One had a post of 0.7 mm and one had a post of 0.8 mm. Even though we are talking 0.1 mm physical difference the visual difference was noticeable. A post of 1.0 mm would appear thick.
Also there are two important things to consider 1) can a post of 1.0 mm get into the hole in the ear and 2) can the 1.0 mm post actually fit into the back catcher?
Yesterday I did an earring design with a post of 0.85 mm (as I assumed that metal shrinkage and polishing would make it 0.8 mm). This model was uploaded to Shapeways without any problems... NO thin walls alert! So now I ordered it and time will tell.
In fact I also did my own design for the back catcher (lock) for the post. I was uploaded to Shapeways successfully without any thin walls alert BUT it was priced €40 by Shapeways in premium silver compared to the earring itself which also came at a base price of €40. I'm quite sure I would sell any back catchers for €40 so that is the main issue with actually printing the complete earring. I might be able to simplify the back catcher a bit and slice a few Euros of the price but it will still be too expensive as I believe that a back catcher in silver plated steel is about €5.
If the two separate items can be printed in the same file the customer won't be able to tell that the catcher is expensive because he/she is buying the complete set. But still, it would make the price less competitive and you would also have to add the fee to Shapeways + you markup.
Cheers, Mike