Understanding the bearing block

[Rogue]

I've been reading around and now I'm going through the process of trying to understand what I've read. I'd be really grateful for a bit of help with the following questions.

I've been looking at the following axis design:

(taken from CNCRouterParts.com)

I'm trying to understand how the thrust bearings works in that setting? As far as I can tell, when assembled they would be in contact with the front/rear of the block not the radial bearing, so what would they achieve? The shaft collar is required here in order to keep the thrust bearings in place, would that be right?


I was under the impression from reading around that a fairly solid bearing could be built using two angular contact bearings back-to-back (so the angles are directed outwards, effectively doing what I think the thrust bearings are meant to do in the picture above?), like so (cue rough and ready CAD):

If so, as the bearings are constrained by the block, the shaft collar in the first picture would not be needed, is that correct?

Also, are "angular thrust bearings" and "angular contact bearings" the same thing?

Apologies for a lot of questions at once, this is largely new territory to me and I've got to the point where I've over-read my level of (current) undertanding. If I don't drag myself back to tackle what you all probably consider basics then I'll get completely lost and learn nothing!