Where did you find those? Someplace online, or local to you? (If the later, do you know the manufacturer and part number?) I've made them by chucking plastic ones into the drill and using sand paper for years, but that is a pain in the butt and it isn't as consistent.
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-IronRaven

When a man dare not speak without malice for fear of giving insult, that is when truth starts to die. Truth is the truest freedom.