I've looked the roller kit picture and the thread by Logboy in the sawmills and milling forum from a couple of years or so ago. I don't entirely understand how the roller kit works. Does it bolt to the mill, and then you take the tip off of the bar? If so, how does the bar attach?
I see that Logboy put the roller kit on in something like 2013 and I bought my mill in 2015, so it would be easy to think I was sold a chainsaw bar attachment with a known defect without that information being told to me. I used the mill a modest/smallish amount in 2015 and quite a bit more last year. Last year I spent a good deal for a second bar after the first tip went out, plus a new tip for the first bar. Now this year the tip is out on the second bar already.
I do not use bar oil, just regular light motor oil. But yes, the bar and chain generate some heat.