Things aren't always the way they should be. Here is a photo with some ABS prints.
The T5 pulley was printed @240°C, 0.35mm layers, 70mm/s feedrate. Something is not right but what? The filament looks like it's been overheated.
The bottom test cube was printed @220°C, 0.25mm layers, 25mm/s feedrate. I thought that lowering the speed would probably result in better quality. Was I wrong! The plastic was sticky and felt like it had been boiling.
The top test cube was printed @185°C, 0.26mm layers, 150mm/s feedrate. That's right, 185°C. I didn't expect it to print at all, after all PLA has a lower extrusion temperature (I can't print PLA at temperatures lower than 180°C) but came out great in comparison with the other two.
While testing this ABS filament I was able to extrude it @135°C !!
I repeated the test many times; at 250°C the plastic makes sounds like frying potatoes ! At 150°C it extrudes happily and silently complete objects.
Conclusion: Every batch of material should be individually tested.Story 2
I was using Slic3r for some parts that involved some 3mm holes and a 22mm one to take a press-fit 608z bearing.
No matter what I did, the holes were coming out the wrong size; I could either get the 3mm right or the 22mm right but not both of them at the same time. In this thread
I described the problem. As it turns out, Slic3r has a feature/bug that shrinks the holes that cannot be turned off, at least in the last version 0.8.3.
I tried Skeinforge and finally managed to print the part correctly. I've been using Skeinforge since then which, although its user interface can be intimidating to the new-comer, gives a lot more control over the result.