Lincoln 180 mig welder?

The previous generation of Lincoln wire-feed welders in that amperage range was the 175 amp units. The top of the line model had a dial that increases the heat like turning up the volume of a radio; the cheaper model had about eight fixed settings that would click into place. I suspect that's the difference in the models you named, too.

Stick welders also come in those configurations. The Lincoln buzz-box (tombstone) welder has fixed settings, while the equivalent Hobart Stickmate uses a crank handle to change the heat, which is referred to as an infinitely adjustable system. With stick welders neither system is clearly better than the other. What the fixed settings system gives up in precision, it makes up for in certainty---infinitely adjustable setting systems tend to creep during welding when the machines get older. I don't think there's a parallel benefit with fixed setting wire-feed welders, though. I think they're cheaper because they're not as good.

All the best, Stan