I have a plastic bucket with a hole cut in the side near the bottom for my shop vac hose. I set the colander in the bucket, which then sits upside down on mesh bucket that my beans are in, sucking the chaff up out of the beans in the mesh bucket. I will either vibrate/bounce the beans to add to the movement or blow the exhaust air from my shop vac through the beans in the mesh bucket with the colander & plastic bucket attached to the shop vac, upside down on the mesh basket.
I'll try to post a few pics. You know a picture is worth a 1000 words.
Jim "Ice Bucket Roaster" De Hoog