These are very large bits that require low speed processing. I dialed the speed on my router and the table started vibrating in a way I had never seen before. I revved it down to around 14,000 rpm and it settled down considerably. But the racquet itself wobbles a lot when you use it. I do 4-5 passes with it and it still leaves ripples and ripples on the finished product. It takes a lot of sanding to get a nice clean surface. I have a lot of Yonico Bits and they work well. But this one is an exception.