Routers are one of the most useful tools for woodworkers, because they are so versatile. A router can be used to cut joints, including finger joints, dovetalis and splines, assuming that you have the correct jigs, of course. Routers can also shape wood and cut panels. Learning to manage the speed of a router is essential if you want to make full use of them.
How to Reduce Router Speed
If a router goes too fast then it will perform just like a speeding automobile, vibrating until it is about to go out of control. Your router has an optimal speed, and that speed will differ depending on the bit that it is being used with. Too slow can be just as bad as too fast. For safety reasons you should try to stay in the sweet spot as much as possible. If you go outside of the sweet spot you could damage the wood that you are working with, the bit, or the router itself.
Common Problems With Speeds
If your router has a variable speed moter, then it will usually run between 8,000 to 26,000 RPG, however the rim speed is more important than the speed of the shank. The rim speed is the volocity of the cutter, at the point which is furthest from the center of the router shank. In the case of a 1/2″ diameter bit, if it is spinning at 10,000RPM that is the equivalent of 15MPH. At 25,000RPM that is the equivalent of 37MPH. As the cutter gets bigger, the speeds get greater – a 3″ diameter bit spins at 90MPH when the motor is doing 10,000RPM – increase the rotation to 25,000RPM and that rotational movement becomes the equivalent of 223MPH!
Once the bit is spinning at more than 100MPH it is in danger of being damaged, and there will be a lot of vibraton. Wear and tear becomes more noticeable, and cutting performance suffers. There is also the risk of tear-out and burn marks on the wood that you are working on, and the bit is liable to become dull quickly. By the same token, if the speed is too low then you could end up with cuts that are choppy, rippled or rough.
So again, it takes experimentation to find the best speeds for you and your router. Hopefully these tips will aim you in the direction you need to go.