Partial Overlay
Partial overlay, also called half overlay, is a cabinet door or drawer-front style where the panel covers only part of the face frame, leaving a visible reveal around the opening. It is sized so more of the stile and rail face remains visible than with full overlay, affecting door dimensions, hinge geometry, and reveal targets.
On the shop floor, partial overlay determines how a door blank is sized and how the hinge package is selected. The CNC program must keep the finished part within the reveal budget after machining, edge banding, and finish buildup. A typical workflow starts with the face-frame opening, subtracts the specified reveal on each side, then applies hinge overlay rating so the door swings clear of adjacent stiles. Because cabinet openings can vary, the operator should verify each opening and frame squareness before nesting. Partial overlay also affects material strategy: show-face edges need clean machining because chip-out will sit directly in the visible gap. During assembly, this style gives some tolerance forgiveness for wall plumb and cabinet squareness, but the reveal must remain consistent from door to door to avoid a lopsided appearance. It is a style/layout constraint rather than a special cutter operation.
- Wrong hinge overlay spec: Selecting full-overlay or inset hinges for a partial-overlay door makes it collide with the stile, open with inconsistent gap, or sit off the frame, usually failing at hanging despite a correctly machined door.
- Cumulative sizing error: Cutting all doors to one nominal size without checking actual opening dimensions lets the reveal drift from cabinet to cabinet, producing uneven margins that are especially obvious on paired doors and drawer stacks.
- Poor perimeter edge quality: Chip-out, fuzzy veneer, or tearout from routing sits directly in the exposed reveal line, so minor machining damage becomes an obvious rejection issue rather than being hidden by the frame.
What is the difference between partial overlay and full overlay?
Partial overlay leaves more of the face frame visible because the door covers only part of the opening, while full overlay is sized to cover most of the frame. The difference changes door blank dimensions, hinge overlay rating, and the target reveal around each door.
Why does partial overlay matter in CNC programming?
The CNC must machine parts that fit within the final reveal budget after edge treatment, finish, and assembly. Any error in part size, squareness, or edge finish directly changes the visible gap around the installed door, so the program must account for hinge cup setback, edge banding, and paint thickness.
What should a shop verify before cutting partial-overlay doors?
Verify opening size, frame squareness, hinge overlay rating, panel thickness after finishing, and the target reveal on all sides. These checks prevent a correctly machined part from becoming an incorrect installed door.