Don't even think of buying a combine without a rock trap. I have been there and done that. You will end up with a load of grief for a bunch of reasons. First the 1420 has a lot of unique parts that are obsolete. The 40, 60, and 80 series parts are easy to get. The unique 20 series parts are not as readily available. Secondly as others have stated one stone can do a lot of damage. I have seen some in excess of $10,000. The rock trap works real well. I have probably picked up over a dozen rocks since I got my 1460 and only one small one went in. It however bent the two front concaves but did not damage the specialty rotor. The two front concaves were getting worn anyway and I replaced them last year. The two new concaves cost over $1100 Canadian dollars (probably $700 US).Thirdly the 1420 is underpowered and the one I drove had no capacity improvement over my old 715. The 1440 is also somewhat underpowered and had the same threshing body as the 1460. If you can possibly find a good 1460 or 1480 with a rock trap and feed reverser, and a rock drum up front on the feeder, you will thank your lucky stars the first time you find a big three inch rock in the rock trap. The 1460 has enough power to handle a 17.5 foot in heavy wheat or a 20 foot header in soybeans. It can also handle a 6 row narrow corn head easily. The 1460's and 1480's are more common and the used price reflects that. The few 1420's I have seen have all been high priced for the capacity. Just my experience.