It had become clear that replacing the entire roller/resistance unit would require more machining accuracy than I was capable of with the wood lathe and pillar drill. So I’ve recently treated myself to a small engineering lathe (please excuse the shoddy mobile phone picture).
Now, it hasn’t entirely escaped me that I’ve just spent more on a lathe than I would have done on an ergotrainer! So I guess now this project is more about scratching an itch than it is about budget..
Am just in the process of gluing up a new MDF mounting for the pillow block bearings, then will set about machining a new roller.