The spiral cutter is a complete waste. According to my experience, it is the worst quality cutter I've ever used. The tool doesn't cut straight, and it keeps slipping out of the collet. The result is a totally uneven mill cut that is unusable. The only positive is that it is cheap, but you get what you pay for. The downside is that it is an unreliable and poorly made product. I would not recommend this cutter to anyone.