Why is ABS worse for press fit parts?

I'm generally used to the idea that I print things in PLA if I want them to be stiff and ABS if I want them to flex. Snap fit stuff works much better in ABS. But for some reason it just doesn't seem to handle metal pieces press fit into it at all. I was printing a part that had a bearing press fit into it. Originally I did this in ABS. If the plastic was at all a tight fit for the bearing, pressing it in would cause the plastic to crack and tear around the perimeter. I had to shave the plastic down until it was just barely smaller than the bearing, and even then there were stress marks along the plastic. When I did the same part in PLA, the plastic just deformed and made a tight fit around the bearing. It wasn't even that accurate of a fit, the perimeter just stretched and the infill compressed.

It wasn't just this one part either, I've noticed similar results with press fit nuts. So, why does inflexible PLA work so much better in this one case?

Seems like you might have poor quality ABS. The best way to insert nuts, etc, is to push them in with a temperature controlled soldering iron set to about 200C for ABS.

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[www.hydraraptor.blogspot.com]

I do press fits in ABS all the time with no issues. Where are you getting your ABS from?

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www.Fablicator.com

I got most of my ABS from [3dprinterstuff.com]

Also, to be fair I got press fit ABS parts to work. But they're by no means as forgiving as PLA. I was more asking if anyone had an idea why brittle PLA would work so much better.

I bought some of their filament off eBay a few months ago. It was pretty soft for ABS and had a lot of moisture in it. Maybe their ABS is just not as strong as others?

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www.Fablicator.com