Allowing for Router Bit Diameter on a CNC Machine

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CNC technology can add a lot of value to a woodworking shop in terms of precision, repeatability, efficiency and quality. Once you have an overview of a CNC machine, you will begin to understand the precision in place throughout the system. This is one of those “garbage in, garbage out” scenarios in which the CNC machine relies on the operator to indicate precise values for projects that are run and the components that are used. If there is a mismatch there will be problems.

A great example of this is when you sharpen a router bit that is used in a CNC router . Let’s say that the router bit was originally ½” in diameter. In order to properly sharpen the bit, the sharpening service will remove a small amount of material in order to re-establish a proper edge on the bit. When you get the bit back, it will no longer be an actual ½” diameter bit, and if you use it with the previous settings in your CNC software you will not produce the results that you expect when you run the job. So, what do you do?

Know the new diameter of the bit. Some sharpening services will indicate the new size right on the bit when it is returned. If not, use a digital caliper to measure it.

Change the bit diameter within your CNC software. Don’t override any system defaults, just find the appropriate place to change for the job that you are running.

Test cut. Run a test cut on scrap material to ensure that you have made the setting change properly.

There are many other tips that can increase your success on a CNC machine, so check out more tips for programming your CNC.