With the chopper in the 'down' position, if you can easily slip a thin strip of 20# paper beside the blade; then the cutter head needs to be adjusted to minimize that clearance. The two, 7/16" hex head bolts on the back side, closest to the cutting head are the ones to loosen 1/4 turn or so. With the head held down, just push on the bar beneath those bolts so that the cutter head is as close as possible to the frame (cutter touching the frame is OK). Watch both blades and keep them centered, or symetrical. Tighten the bolts slowly, watching to make sure that the clearance doesn't change while tightening.
For wooden fillets, make sure the blades are mounted using the screw holes that put the blades on about a 45 degree angle. The screw holes that put the blades closer to parallel to the frame work best for plastic.
You should now be able to cut paper with the chopper without a problem. I forgot to mention that if there are burrs on the frame, you'll have nicks in your blades. Polish the burr.
A drop of oil every now and then on the sliding sleeves helps. I prefer Bernina rotary hook sewing machine oil for all the moving parts in the store that need lubrication.
Sorry that I didn't have the camera and chopper at the same place and time or I would have used photos. If needed, that can be done later.