What is a CNC? CNC stands for computer numerically controlled. The term “CNC” is a prefix for anything that is programmed by a computer and automatically completes a task. You can have a CNC router, plasma cutter, laser cutter, 3D printer, welder, etc etc. These types of machines are starting a new era for the world around us. They are all around us in our everyday lives, even in the woodworking shop. I was fortunate enough to get a CNC Shark HD with extended bed by Next Wave Automation available at your local Rockler or Rockler.com.
A CNC system brings a whole host of opportunities in a woodworking shop. The best feature of a CNC system is the accuracy and repeatability. Simply setup a few stops to register your parts and run your operation. Once complete, switch the material and start the process again.
Now that my CNC unit is up and running, we need to make a spoil board. A spoil board is critical to having a system that can handle through cut operations. A spoil board protects the factory surface (metal, plastic, wood, etc) from being cut into. I have also incorporated threaded inserts to be utilized during cutting to hold down the material to the work surface.
I started out by cutting 3 pieces of MDF to rough size at the table saw. I applied glue to the surface and used 8 23-gauge pin nails in the corners to hold the top boards in place so they do not move during the drilling and screwing process. Once the glue was applied, and the pin nails in place. I pre-drilled and drove pan head screws all over the surface to apply clamping pressure. Once the glue dried, I removed all the screws and cut the board to final size at the table saw.
I then marked out a series of lines to create points on the CNC table. One group of holes lines up with the t-track table to hold the spoil board down to the aluminum table. The other group of holes is strategically placed to hold 1/4-20 threaded inserts to be used to clamp the material to the surface with commercially made or homemade hold downs and a bolt.
I then placed the spoil board on the CNC table and used a pattern marker to mark the position of each hole on the table. I remove the spoil board and place all the bolts over the marks and prepared to drop the spoil board over these bolts. I countersunk the holes to help feed the bolts into the holes. It was a bit tricky to get everything lined up but eventually it all lined up.
Once the spoil board was in place, I then used a washer and lock nut to secure it to the CNC. I used plenty of connection points to make sure it is secure for two reasons: 1) the spoil board cannot move and 2) the threaded inserts will be used as clamping points, during the clamping I don’t want the spoil board to flex.
After everything was secure, I programmed a pocketing program on the computer and used a 1.5″ spoiling board bit to make a 1/16″ deep pass to make he surface perfectly parallel with the CNC gantry.
Once the program was complete, the surface that was within the cutting area has been perfectly flattened and is now parallel with the CNC gantry. Thank you for visiting