Using a CNC to solve unusual woodworking challenges.

Do a search for what a 3-axis CNC is capable of, and generally you'll find people cutting flat work on their CNC bed. Some have a radial 4th axis to do simple or complex cylindrically confined projects. Most come with limits describing the width, length, and vertical cutting range projects should be confined to.  Many CNCs are capable of solving far more woodworking challenges, but you'll need to literally think outside that cutting limits box.

In 2004 or so purchase my own 3-axis CNC Shark. I cut flat parts for student furniture designs in my garage for the next few years. Bumping into the area limits of this small CNC, I purchase a larger Probotix CNC for my home shop. A desire to cut tenons on the ends of long stretchers led me to open up one end of my Probotix CNC for vertical access down to the floor. Once opened up, I realized with some jigging I could clamp parts at angles other than 90 degrees. Four or five revisions/updates of my compound angle clamping jig have led me to what I know can be done today.  What a CNC can do doesn't stop at the spoil board plane. 

Opportunities arise when you think about using more than just the flat bed of a CNC to clamp your parts to.   Many come with 2 motors pushing/pulling the gantry, which may mean there is nothing running under the bed.  Once you consider using the space under the bed, the next step is to make access to it. In my case I initially left open the front 1/4 of my CNC's bed, and mounted the CNC on an open frame with no top on it.  I now have access to all the vertical space between the bed of my CNC and the floor.

With access, the next step is to come up with a way to clamp parts under/inside the frame to hold them rigidly where the CNC can reach the areas that need to be cut.  

If you clamp your parts or jigs to one of the frame rails, make sure the rails are securely mounted and can't be rotated or racked or bent or flexed when under load. I made a jig that clamps to the front rail as I knew it couldn't rotate the way the frame is assembled: My Jig 

Bridges that span the frame, clamping jigs, accessory rails, and even the frame rails themselves can contribute to the potential woodworking challenges you can solve with a CNC. Bridge support.

T-slots, either in track strips you can buy or the frame member extrusions themselves come in very handy for attaching jigs/bridges/cross rails to.  One example is my bridges that screw into t-nuts in the frame rails and themselves have t-track down their middle to use for clamps that hold your project boards down. Another is my advanced compound angle clamping jig that bolts into the inner face and top slots of the front frame rail.  Sections of t-track could be installed on such a jig, but my current version has holes for c-clamps to hold project boards and reference edges/stops to. 

It is below the bed where opportunities for creative CNC cut solutions live.  To take advantage you'll need creative jigging to clamp your project parts down there.

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Comments and questions encouraged and appreciated!