Quote Originally Posted by catalyst View Post
I have two other issues/questions:
1. One of the things I notice with rafting and supports is that my bottom layers (or underside of the build object) aren't anywhere near as clean as the top and sides. What is that an indicator of?

2. I'm not sure how to resolve that, either. So for clarification as to my parts not fitting - when I print shells - do those count against my tolerances - if so how much? IE, if I print a 2mm radius circle cutout, will a 1.99mm object fit into that? How do I know how much room to give the build so the objects freely fit inside?
For 1, The part in contact with the raft will never look like the other surfaces. The bottom slightly fuses with the raft layer, so there will be some defects when you pull away the raft. The look can be improved, but only to a point. You can tweak the raft setting in S3D. My settings for Inland ABS are:
Raft layers 2.
Offset from part 2mm - how far from the each of your part the raft extends (I'm thinking about bumping this to 2.5 or 3 because I've been getting some curling).
Separation distance of 0.2mm. This is how close the part is to the raft - higher values will have less impact on the look of the finished part. Make it too high and the part won't stick to the raft.
Raft infill of 70%, lower values make the raft easier to remove but can affect the look negatively.

For 2, it kind of depends. This will vary a bit from printer to printer and how well it is calibrated.
Instead of drilling and tapping holes, you may want to consider knurled inserts, (sometimes called "press fit expansion inserts"). These are metal inserts you just press into the part, you can then use a machine screw into the insert. They are more forgiving on hole tolerances. I've used them on several models and they work great and look more professional.

http://www.mcmaster.com/#inserts-for...3bm0xfifmietqj