(quoted from post at 05:35:45 06/03/19) Go with the 489 but inspect any unit for wear. See if the gear boxes are to the proper level with gear oil if possible. Major components are expensive to replace. They still
bring around 3,000 dollars if in good to nice condition. So maybe with another 489 that has a good hitch but other problems you can build one good machine from two so-so
units and come out ahead.
My brother has run a NH489 for about 35 years now on the home farm. He just, last year, had to buy another one and swap parts over, because he essentially broke the frame.
But, he does 30,000 to 40,000 small squares a year.
(I honestly don't know how he sits on the tractor seat that long...)
One thing that I would look at with a 489 is where the tongue connects to the frame of the mower. The first few years they were made, there was just a large bolt that made this connection (if I remember, there was maybe a bushing in the hole with it for pivoting). This was a weak system. The bolts would break. Sometimes the tongue would crack where the bolt went through. The box tongue also twisted and cracked on him once or twice.
After a couple of years' production, NH modified the tongue's pivot to use an even larger pin with just little bolt to hold the pin in place. These seemed more robust.
After some initial growing pains, my brother replaced the tongue on his, back in 1986. He also made a couple of strategic welded reinforcements on the new tongue... and, even with the older, weaker, version, it lasted right up until last summer.
The 489 is much easier on the header springs, since only the header "floats" and goes up and down. The conditioning rolls stay stationary.
The NH488 and most other brands of haybine had the header and conditioning rolls mounted as one large, heavy piece that floated up and down together. Much more stress on the springs. Didn't "float" nearly as well as a 489.
A 489 is very good at following ground contours for that reason.