Is this wheel salvageable?
 

I've been fixing bikes this summer, mostly kids, lady mountain bikes and cruisers. Thanks to this forum I've been sailing along smoothly. Seems like season is ending, so I decided to build myself one. Picked up this "higher end" Genesis, with weird wheels, which I would like to keep, however, the rear has a missing axle and internals. I have a bunch of spare rear wheels with good axles, however, not sure how to reach that broken piece inside. Is it possible with common household tools?

https://cimg0.ibsrv.net/gimg/bikefor...2d9b5a0d25.jpg
https://cimg4.ibsrv.net/gimg/bikefor...b079afa81e.jpg

Or, would it be easier to replace the entire assembly with cassette into this rim?

Maybe; you'll have to remove the freewheel first, and determine if that broken piece is a dust cover, or part of the hub. You'll probably need a Park Tools FR 7 Freewheel Remover for it. Once checked to make sure everything is in good condition in/with the hub, (and I'm not sure because of the picture, but the hub's race appears pitted), go to your LBS and get a replacement axle for an 8-speed (either nutted or with quick release, I think 130mm, but someone more knowledgeable should chime in promptly; they should come with cones, locknuts, spacer, and necessary washers. If quick release, you'll need to buy the skewer separately.). Also, if you plan to use your new bike heavily, you may want to reconsider using such a hub, as it exposes a lot of the axle on the drive side, making it prone to bending. Maybe relace the rim (if it is in really good condition and, the spokes can be salvaged also) to a cassette hub of your liking? Anyway, good luck with the project!:thumb:

So the various axial elements (freewheel, bearing cup, hubshell) are no longer aligned. It's likely that there's broken/cracked metal inside. Fixing that in a hub is not cost effective. But pull the freewheel and take a deeper look. Andy

Looks like the bearing race is toast. New hub, which in your case would probably mean a different used wheel.
That's a Free Wheel hub. Cassette hubs are a very different animal.
Freewheel or Cassette?