Canadian Boy, The Disruptor lugs are installed in the grates rather than the concaves. There are 3 concaves in the front of the rotor which are adjustable for height to control the threshing, and 3 grates in the back of the rotor which are just for separation. The clearance between the grates and the rotor does not change when you adjust the concaves. If your machine was purchased in wheat country you may have the slotted grates, which will not accept the Disruptor. Take a look inside the machine at the rear of the rotor. If you see oblong holes with rounded corners about an inch wide and maybe 3" long you have the slotted grates. In the interest of saving money, if you find that you have slotted grates, I would just buy one keystock grate and place it at the very back of the rotor. The keystock grates look similar to the concaves and have rectangular holes with square corners formed by welded keystock material. Mount all 9 Disruptor lugs in that rear keystock grate in a spiral pattern, 3 sets of 3. As the straw exits the rotor the lugs do a nice job of chopping it up, even though it doesn't seem too intuitive by looking at them. In dry straw I would prefer it over a JD 9600 chopper which is what we were running with. If you find that you want even more chopping action, you can simply add the Rice Spice rotor bars to the rear of the rotor to run next to the Disruptor lugs. This will give you a slicing action between the lug and the spike. I've not tried this, but would guess that nearly any wheat straw would come out of the rotor very well chopped. I would suspect that with the rice spikes you will use some horsepower, but we really didn't notice much difference just running the Disruptor lugs without spikes. Bottom line: I don't think you'll be disappointed.
