In brief, the difference between a disc plow and a disc tiller is that on the tiller, the discs are on an axle, with a bearing at each end, and maybe 2 more about every 4-5 blades on the big ones, whereas on a disc plow, each individual bottom has its own bearing, and they are pretty big, too. The advantage is that a disc plow will roll over a rock, or cut through a 3" tree root. Hence their other name "new land plow". If you are looking for a picture, try the old allis web page. I have a 3 bottom Allis Chalmers (Athens) disc plow that I use every couple of years- it pulls real easy in conditions that a moldboard plow won't. If you do a google search, use the words fire plow, disc plow, or new land plow. I know there is a company in Texas, or somewhere out west that still builds them as fire plows.
