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This is what you need in order for a rotating power tool to hold the bits in place. This router comes with a 1/2-inch collet that doesn’t work very well and is dangerous to use. On the first time I used it, I put in a 2-flute cutter with a 1/2-inch shank and fully tightened the collet with the wrench that came with the tool. It started to chatter after about 20 seconds of light cuts. When I stopped the router, I was shocked to see that the collet had come loose. In this picture, you can see where the collet almost doesn’t touch the shank even when it’s “tight.”
