I used a hole saw to open the center hole in the 5/16" steel plate sprocket. I tried drilling the hole with a Milwaukee steel tooth hole saw. It boomed hard and stopped cutting completely after a little over halfway. So I needed another hole saw to finish the job. I found this one and it looked very durable and had ceramic teeth. I expected him to easily finish the hole on the other side. It really broke through after running my little drill for almost an hour. It throbbed hard and only seemed to cut briefly after applying oil to the hole. But in the end she passed. And she seemed to cut just as well at the end as she did at the beginning. The vibration may have been increased by a bad center hole. Since the sprocket came with a 1" center hole, the sprocket was clamped to a 2X4 line. And the center drill went into the rather soft wood. There may not have been adequate centering support. Another factor could be the rotational speed. I set my little drill to its lowest speed, but I suspect it was still faster than ideal speed.