How to Program a CNC Router

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A CNC router allows woodworkers to turn out precisely carved pieces repetitively. This capability makes the machine popular with violin makers and other woodworkers who need to produce a number of similar pieces quickly with close tolerances. The exact method of code entry varies with the make and model of the CNC machine, but the general practice remains the same with most commercially available models. When programming the router, the cutting tool properties and characteristics of the wood must be taken into account to reduce the possibility of tear-out and burning.

Enter the dimensions of the work piece into the command console. Standard CNC measurements work on a three-axis system. The X axis represents the length of the piece, the Y axis is the width and the Z axis is the material’s thickness.

Create the milling program. Enter the depth and direction of each cut as well as the number of passes required to reach the finished cut depth. Repeated shallow cuts reduce the risk of tear-out.

Select the router path and speed. The path and direction of each pass is best determined by the piece’s final shape. Adjust the cutter speed for the properties of the wood. Fine-grained hardwoods like maple burn quickly. Fast, light passes work well with this type of material. Open-grain hardwoods like oak dissipate heat rapidly. Slower, slightly heavier cuts can be made safely with these woods.

Save the program and test it with scrap wood. Testing the initial program on a scrap piece allows you to correct mistakes in programming before you ruin an expensive piece of material.


  • No two pieces of wood are exactly alike. A small amount of tear-out or burning can happen even with the most carefully tested program. Sharp carbide bits produce better, more consistent results than high-speed steel. Carefully inspect each blank for raised grain and run-out. Place these questionable sections of material in areas with the least amount of cutting whenever possible.


About the Author

Finn McCuhil is a freelance writer based in Northern Michigan. He worked as a reporter and columnist in South Florida before becoming fascinated with computers. After studying programming at University of South Florida, he spent more than 20 years heading up IT departments at three tier-one automotive suppliers. He now builds wooden boats in the north woods.

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