There was an actual Molfres at the Swiss school I attended, it was highly regarded. There's a very fine feed and apparently it's practically impossible to do damage to the balance. I've always turned off the hub (which is what it grinds off), so I never used it. When actual Molfres machines come up they always go for a pretty penny. Money I always figured was better off adding to the lathe accessories.   A quick vid that shows how it works.