Take a look at this downloadable
model by Improbablecog. You can download this and take measurements of those slots. The designer, hand finished it so you can clearly
see what slots printed and what slots merged together.
Take a look at this image.
And a cross section diagram I did on the model.
As you can see, the seventh slot merged together. Measuring the clearance of that seventh slot we get 0.235 mm. Yet, the sixth slot
next to it did print and its clearance is 0.316 mm. So keep it above 0.316 mm to have it print, right? Well, yes if you're going to hand finish it, no if you're going to
leave it as printed. Here's why. Take a look at this
model from the same designer. You can also download this and take measurements.
As you can see in this image,
The central slots printed, but being unfinished beyond Shapeways' bulk finishing they are kind of rough and if
we measure the clearance we see that it is nearly double.
Keep in mind also that there is some variability from print to print in stainless too, so I would add another two tenths of a mm for that. I have spent time on this reply
cuz I am also interested in these things as I am learning about it too and I will come back to this thread for future reference.
James