To cut an aluminum spinner you need Carbide bits for your dremel. And a small tube of synthetic grease. Put some grease on the bit so the aluminum will not stick. Re- apply the grease now and then. If you do not know what you are doing stay away from CF spinners. The dust from cutting them is wicked. They do not stand up to abuse. They need to be inspected every flight. It takes about 5 applications of loctite to get the bolts to stay tight.