First - welcome to the forum!
I just tried with 2 conical parts and the default was concentric. These parts were very simple and created by revolving a sketch around an axis. I suppose it is possible if the parts were modeled in another way, that preference may shift to another default mate.
I'm on 2014 SP 2.
Thanks for checking on this. Ive done similar tests with simple peg and hole shapes and had the concentric mate working fine
The problem for me is that i only updated 3 days ago and i was working with the exact same parts that i was working on in 2013 (absolutely no changes at all to the model) and that issue wasnt there. For some reason it just seems that the parts i have been using previously no longer want to mate concentrically (they will mate but only if i specifically select it and not defaulting to this as they had previously).
Never mind though i guess its just one of those things. good to know that its working elsewhere though so it must just be something on these parts
I've found the same issue, creating a concentric reducer shape, that won't remain concentric when the diameters at each end become greater in difference. I tried many different work arounds but the only that worked was creating the part in my 2013 version and opening it in 2014.
The lofted bend in SW 2014 has a few other bugs that I avoid by using 2013 to create that part.
SW 2014 seems more sensitive to the features you are mating.
1. It tends more towards coincident mate if you use a round edge of one of the parts instead of a round body (which makes sense it gives you more control over the logical way it should be mated, I think). A coincident mate can kill 2 birds with one stone by mating in an axis (x y or z) AND keeping them concentric.
2. The parallel mate gets defaulted to when another concentric mate will fail (which I was hoping they would add.....flat surfaces in 2013 first errored out when I tried to do a parallel with a distance between them ....it should have defaulted to parallel next IMHO).
So if 2 parts have 2 alignment holes, you can always do 1 concentric mate no problem but if they are not the same distance or angle, it will default to parallel (which my brain doesn't really work very well with, It just doesn't compute parallel relations between 2 holes very well but I'm sure it's perfectly legit)
Hope this helps.