To use router bits safely (and to get the best results from your router), the router bits need to be installed properly into the router's collet. Improper installation of your bits can cause excessive chatter and could increase the likelihood that the bits will break when in use.
First of all, before beginning any routing operation, check your bits to make sure that they are clean, relatively free of pitch, and most of all, sharp. If the bit is dull, chipped, is excessively burned or has any other defect, it should be sharpened or replaced before use.
When installing the bit into the collet, do not tighten the collet with the bit "seated." Instead, insert the bit until the shank reaches the bottom of the collet, then ease it out about 1/8 - 1/4" before tightening the collet. When the bit is tightened, there should be no less than a 3/4" length of the shank in the collet. If your bit has a shank that is too short to ensure 3/4" is encased within the collet, then the bit should be replaced.
There are a few other safety measures to keep in mind whenever you use your router. First of all, remember to always wear appropriate safety gear, including safety glasses and hearing protection whenever you use your router.
Second, be sure to set your router to the proper speed for your router bit. Setting your router to an incorrect speed will not only affect the router's performance, but also can cause the bit to break much more easily.
Also, before beginning any routing operation, be certain that you give the router's motor time to come up to full speed for the chosen setting. Beginning to route before the bit is at full speed can give less than desired results.
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