I have a D180x300 (and a BF20 mill, purchased a couple of years later).
About one year ago, when I berserked* my mill, I ended up with writing the entire story to the Optimum guys (step by step, simptom, possible cause, fix, through the [initially] gentle hammering to the happy ending of dropping the motor on the floor) asking for the price of a list of replacement parts.
Two days later, I had new motor, electronics and replacement gears at home, at no cost: they recognized the original problem was covered by the warranty** and the subsequent 'fixings' were caused by that. - I luv 'em. -
As for the lathe, it never gave me problems: would buy another (though that new one would be more powerful, longer, larger, heavier and maybe slower at the minimum speed. I could do with a Nortion gearbox, too) ;D
Marcello
(BTW, my avatar shows the gear extractor I made some time 'after', to remove the motor gear of the mill).
*) really.
**) I had not even dared mentioning "warranty" in a letter containing words like hammering and dropping...
