Originally Posted by
Kontact
Many hubs like yours have axle ends that can be pulled off to service the hub bearings. ..snip...
It is held in place by friction.
Some end caps are threaded on. For example, some Bitex axles use threaded caps, and some other brands' hubs are made by Bitex and so may share that design. Off the top of my head, (some, maybe all) Origin8 hubs are Bitex.