Supporting Assembled Projects Beneath the CNC.

The open frame design of Probotix' CNC machines  proved useful when this challenge came up.  A student of mine had already assembled the body of her cabinet. We needed to cut a circular array of holes at each corner on the bottom board.   The only way to cut this hole array accurately was to use the CNC.

Her design has no back panel.  This permitted using bridging supports I designed that could pass through the body to hang it from the CNC frame. 1/4" dowels were installed along the top of the bridges to position her bottom board square and centered in the frame. C-clamps locked the cabinet to one of the bridging supports.

The bridges are made of 3/4" plywood.  A 6" tall side piece joined to a 2" wide top piece. The vertical piece is an inverted arch, thicker in the middle of the span where the greatest load would be.  The top pieces have holes in the ends so they can be bolted into the side frame members of the CNC.

First test of these bridges worked perfectly. The cabinet was lifted up into the frame, the bridges passed through it then dropped onto the side frame members. We slid the bridges to either end of her cabinet to be right under where the CNC work would happen. The bridge ends were locked into the frame, and the dowels held the cabinet securely in position on the bridges.

The tapered legs in this photo were cut using the rotary axis on another Probotix CNC. The pin arrays on the top end of them were cut using an adjustable angle clamping jig I designed that also fits into this CNC t-slotted frame.

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