Dado
Is a dado the same as a groove?
In shop usage, a dado is a groove cut across the grain; a groove is the broader term, while a dado usually implies the joinery function for a mating panel.
How is a dado handled in CNC CAM?
Most systems treat it as a pocket or a dedicated dado toolpath, with width driven by tool diameter and compensation strategy rather than by hand layout.
Why cut the dado slightly narrow?
Shops often cut slightly undersize so inconsistent board thickness still yields a tight, clean joint after calibration or minor shoulder machining on the mating part.
A dado is a rectangular groove or slot cut across the grain of a panel so another part can seat into it; in cabinetmaking, the groove width is typically matched to the mating panel thickness, and on CNC systems it is commonly programmed as a pocket or line-based machining operation.
In CNC cabinet and millwork workflows, dados locate and lock shelves, dividers, tops, bottoms, and partitions with repeatable geometry instead of relying on fasteners. On a flatbed CNC, the dado is generated from CAD/CAM as a pocket path or specialized dado toolpath, with tool diameter, depth, and allowance set from material stack-up and required fit. Production shops often size the dado slightly undersize relative to nominal sheet thickness or machine the mating part to a controlled shoulder so inconsistent plywood thickness still assembles without gaps. For blind or stopped dados, CNC software may automate slot location but require end cleanup or specific toolpath strategy depending on whether ends must remain square and hidden. In millwork assembly, the joint improves squareness, glue area, and positional accuracy, common in cabinets, casework, and panelized construction.
Wrong material thickness assumption: Sheet goods are rarely exactly nominal thickness, so a dado cut to nominal dimensions can be too tight or too loose, causing press-fit blowout, glue starvation, or visible gaps.
Toolpath/bit mismatch: If the CAM database tool diameter does not match the actual cutter, the machine can generate the wrong slot width; this shows up as poor fit, excess cleanup, or a slot that no longer matches the mating panel.
Stopped-dado end quality: Blind or stopped dados cut with an inappropriate strategy can leave rounded ends, uncut islands, or end tearout, requiring chisel cleanup or causing the part to bottom out before seating fully.