What Is Concealed Hinge Spatial Clearance? (Cup Depths)
Concealed-hinge spatial clearance is the room a hinge needs inside and around a door to fit, swing, and avoid contact. For a representative 35 mm cup hinge, the bore is nominally 13 mm deep, but these dimensions are not universal. Check the exact hinge drawing, door construction, edge setback, and full swing before drilling.
Your goal is not just to make the hinge cup fit. The door must also keep enough material behind the bore, the hinge arm must move without striking nearby parts, and the closed door must land at the intended reveal. A door that closes once without rubbing has not yet passed a full clearance check.
I use “spatial clearance” to mean both the space occupied by the hinge within the door and the space needed as the door moves. Cup dimensions and drilling positions depend on the hinge model. The International Residential Code and International Building Code do not set a universal concealed-cup drilling layout; ANSI/BHMA A156.9 addresses cabinet-hinge performance, not one standard cup depth for every hinge.
Plan the Hinge, Door, and Surrounding Geometry
Before marking a bore, identify the exact hinge and the door it will sit in. Clearance depends on the cup, mounting plate, door thickness, overlay or inset layout, and nearby objects. Start with the hinge maker’s current drawing, then check the actual door and cabinet rather than relying on a generic template.
Record these details:
- Hinge brand and model, including the matching mounting plate
- Door thickness and local face construction
- Overlay or inset condition, plus the planned reveal
- Door-edge shape, including bevels, profiles, or local thinning
- Nearby walls, handles, drawers, appliances, and trim
- Required opening angle and any stops or limits
Overlay describes how far the door covers the cabinet side when closed. Inset means the door sits within the cabinet opening. These setups affect hinge position and swing, so the same cup location may not suit both.
The cup drawing should identify the bore diameter and depth, the edge setback, and any door-thickness limits. Look for the maker’s opening-angle, overlay, and clearance diagrams too. If the door is profiled or has a veneer, check the material where the cup will actually sit; the nominal thickness at the edge may not reflect the thickness under the bore.
A drawing is a starting point, not a substitute for a fit check. I compare its dimensions with the door and surrounding parts before I mark anything. If the model or plate is uncertain, pause and identify it first. Next step: confirm the full hinge set and measure the door at the planned cup location.
Check Cup Depth, Edge Setback, and Swing Clearance
Cup depth controls how much material remains behind the hinge. Edge setback controls where the cup sits across the door. Swing clearance concerns the space needed by the door edge and hinge arm as the door opens. Check all three against the exact hinge drawing; none can be safely inferred from the closed-door position alone.
A common reference example is a concealed hinge with a 35 mm cup and a nominal 13 mm bore depth. In one referenced hinge family, the maker’s K dimension ranges from 3 to 7 mm. K measures from the finished door edge to the nearest edge of the cup bore, not to the cup centerline.
For that 35 mm bore, the radius is 17.5 mm. The centerline distance from the door edge is therefore 17.5 mm + K, or 20.5 to 24.5 mm across that K range. This arithmetic applies to that bore and K definition; it does not make those values universal.
| Check | Representative value or method | What to confirm |
|---|---|---|
| Cup-bore diameter | 35 mm | Exact hinge drawing |
| Nominal bore depth | 13 mm | Model-specific maximum and door limits |
| K edge setback | 3–7 mm for one family | K definition and allowed range |
| Centerline from door edge | 20.5–24.5 mm for the example | 17.5 mm radius + K |
| Material behind bore | Door thickness − actual depth | Local thickness and maker’s limits |
For a uniform 16 mm door and a 13 mm bore, the calculation leaves 3 mm behind the bore. That is a measurement, not a universal safe-skin rule. A thin face, veneer, profile, or void may leave less sound material than the overall thickness suggests. Check the panel construction and the hinge maker’s minimum door thickness and bore-depth requirements.
To assess swing clearance, use the hinge maker’s overlay or reveal drawings. Mock up the door’s travel and check the arm, door edge, pull, and nearby surfaces through the full opening. A wall, handle, or adjacent drawer can block travel even when the cup fits neatly. Next step: reject any layout that risks face breakthrough, weak cup fixing, or contact during movement.
Bore, Install, and Adjust the Hinge
Accurate drilling begins with the finished door edge and a controlled depth. Mark K as the drawing defines it, set a depth stop to the specified cup depth, and test the setup on matching scrap. Do not deepen a bore just to force a hinge into place; a poor fit may damage the door or weaken the fixing.
- Confirm the layout. Recheck the model, plate, door thickness, edge profile, K value, and bore depth. Make sure the marked face and edge are the finished surfaces.
- Mark the bore. Measure K from the finished edge to the bore edge, then mark the centerline using the correct radius. For a 35 mm bore, that radius is 17.5 mm.
- Set the tool. Use a suitable boring tool and a depth stop set to the hinge maker’s specification. Keep the bore square to the face. Avoid an uncontrolled freehand cut.
- Test first. Bore matching scrap with the same thickness and construction. Check depth and cup fit. Scrap that is thicker or built differently may not reveal a breakthrough risk in the actual door.
- Install the hardware. Fasten the cup and mounting plate using the maker’s specified screw pattern and hardware. Check that screws do not interfere with the cup, arm, or other fittings.
- Adjust carefully. Set overlay and reveal with the hinge’s adjustment features, following its instructions. Do not use adjustment to hide a misplaced bore or a door that binds.
If the door is thin, veneered, locally carved, or otherwise uneven, measure the remaining face material at the bore location. There is no generic skin thickness that guarantees a sound result across all door types. If the planned bore could break through or leave a weak fixing area, select a suitable hinge and door layout before drilling. Next step: inspect the installed cup and fixing before cycling the door.
Verify Full Travel, Reveals, and Fixings
A completed installation needs checks with the door both closed and moving. Confirm that the hinge arm, door edge, pull, and nearby surfaces remain clear throughout travel, and that the cup and screws sit as intended. Then inspect the reveal and fixing for signs of contact, breakout, or looseness.
I treat a closed-door check as only one part of the inspection. Open and close the door through its full intended range at a steady pace. Watch the hinge arm and the nearest edges, not just the front gap. If the door stops short, rubs, or shifts, identify the cause before making further adjustments.
Illustrative layout checks
- Uniform 16 mm door: A 13 mm bore leaves 3 mm by subtraction. Measure the real panel at the bore and verify the hinge maker’s thickness and depth limits before using this layout.
- Profiled or veneered door: The face may be locally thinner or less uniform at the cup. A nominal 13 mm setting alone cannot establish how much sound material remains; inspect the section and test matching material.
- Door beside a wall or pull: The cup can be correctly placed while the door edge or arm still contacts the surroundings. Compare the planned swing with the hinge drawing and test the full travel before final adjustment.
These are calculation examples, not reports of specific installations or guarantees of compatibility. If a check shows contact, breakout, or weak fastening, stop and revise the hinge choice or layout rather than forcing the door through its travel.
Conclusion: Concealed-hinge clearance is a model-specific fit problem, not a single cup-depth number. Confirm the drawing, calculate setback from the correct reference edge, protect the door face, and test the full swing. Final check: the cup fits, the fixing is sound, and no part binds through the intended travel.
Frequently Asked Questions
These answers cover common questions about cup depth, edge setback, and the space a concealed hinge needs. Use them as checks, not replacements for the current drawing for your exact hinge and plate. When model details differ from a general example, the maker’s instructions govern the layout.
What is concealed hinge spatial clearance?
It is the space a concealed hinge needs within the door and around it as the door moves. It includes cup depth and position, material behind the cup, hinge-arm movement, and clearance from nearby surfaces. The exact requirements depend on the hinge model and door layout.
How deep is a 35 mm concealed-hinge cup?
A representative 35 mm cup hinge has a nominal bore depth of 13 mm. That figure is not universal. Check the current drilling drawing for the specific hinge, including its permitted door thickness and maximum depth, before setting a drill stop.
How do I calculate the cup center from the door edge?
If the drawing defines K as the distance from the finished edge to the bore edge, add the bore radius to K. For a 35 mm bore, the radius is 17.5 mm, so centerline distance is 17.5 mm + K.
What does K mean on a hinge drilling drawing?
K is the edge setback from the finished door edge to the nearest edge of the cup bore on the referenced hinge family. It is not the distance to the cup center. Confirm the maker’s definition, since dimensions and allowed ranges vary by hinge model.
Is 13 mm a safe depth for every door?
No. A 13 mm bore can leave too little material in a thin or locally thinned door. Check the actual thickness at the bore, the panel construction, and the hinge maker’s limits. Do not rely on a generic minimum face-skin thickness.
Does a 35 mm cup always need a 20.5 mm centerline?
No. That centerline follows from a 35 mm bore and K of 3 mm. If K differs, the centerline changes. Use the exact hinge drawing and its definition of K rather than copying a measurement from another model.
How can I check door-swing clearance before drilling?
Use the hinge maker’s overlay, reveal, and opening-angle drawings. Mock up the door’s intended movement and check the arm, door edge, pull, and nearby wall, drawer, appliance, or trim throughout travel. A closed-door fit does not confirm swing clearance.
Can I deepen the bore if the cup does not sit flush?
Do not deepen it by guesswork. First check the hinge model, bore diameter and depth, tool alignment, and door surface. Further cutting can break through the face or weaken the fixing. Follow the maker’s instructions and revise the layout if it does not fit.
(This article was written by one of our staff writers, Garrett Vance. Visit our Meet the Team page.)
