45 inches is max. 49 inches you can probably get away with depending on the shape. It has to fit in the size-wise. I'm guessing an espresso machine is roughly cubical in shape and probably won't fit in the size-wise like a rollaboard would.

I forget if there's a restriction on weight, and couldn't find it on the web site, but 41 pounds seems like a lot. It depends on the aircraft you're flying. The big birds can hold a lot in the overheads. Are you in economy or business? You can probably get away with this in business, less likely in economy IMO.

May also depend on the friendliness of the agent checking you in.

If it is in the original box, which presumably contains some kind of packing to keep the machine safe during shipping, why not just check it as a piece of luggage? Unless you are traveling to a country that doesn't permit boxes as checked luggage.