Hinge Boring Explained: What to Tell Us When You Order Doors

Hinge boring is drilling the 35mm round cup holes in the back of a cabinet door so concealed hinges can be mounted. To have doors bored correctly, you need to tell us four things: that you want them bored, which side the hinges go on, how many hinges per door, and where the hinges should be placed if you’re matching existing hinge plates.

The Basics of Concealed Hinge Boring

Most modern concealed (European-style) hinges, including those from Blum and Salice, mount the same way:

• Cup diameter: 35mm, the industry standard.
• Cup depth: about 1/2" (roughly 11.5–13mm, depending on the hinge).
• Cup distance from door edge: commonly 3–6mm from the door edge to the edge of the cup hole. This setting, sometimes called "boring distance" or "tab," affects overlay. Follow your hinge manufacturer’s spec.
• Screw holes: some hinges press in with dowels, others screw on. Pilot holes for press-in dowels are bored at the same time as the cup.

Because the cup hole is a fixed size and shape, the hinge cup is the same across many hinge types. What changes between hinges is the arm and mounting plate, which set overlay and the cabinet type.

What to Tell Us When You Order

1. Bored or not bored

If you’re using concealed hinges, order doors bored. If you’re using exposed hinges, butt hinges or you plan to bore them yourself, order them unbored.

2. Hinge side

For every door, list the hinge side as you face the cabinet from the front: left or right. Pairs of doors in one opening get one left and one right.

Doors that are top-hinged (flip-up) or bottom-hinged need a note, because they use different hardware.

3. Number of hinges

General guidance for typical 3/4" doors:

Wide, heavy or glass doors may need one more than the chart suggests. Hinge manufacturers publish their own guidance by door weight and size, so check it for unusual doors.

4. Hinge locations

If you’re putting new doors on existing cabinets and reusing the existing mounting plates, the new hinge cups must line up with those plates. Measure from the top and bottom of the old door to the center of each cup hole and give us those numbers.

If you’re installing new plates, the standard approach is to center the cups a few inches in from the top and bottom of the door, commonly around 3" to 4". You can then position the plates to match.

How to Measure Existing Hinge Locations

1. Take one old door off and lay it face down.
2. Measure from the top edge of the door to the center of the top hinge cup.
3. Measure from the bottom edge to the center of the bottom cup.
4. If there’s a middle hinge, measure from the top edge to its center.
5. Check two or three doors. If they’re consistent, one set of numbers covers them. If not, list each door separately.

Note: if the new doors will be a different height than the old ones, the top measurement may still line up with the plates, but the bottom one won’t. Base your numbers on where the plates are on the cabinet, not on the old door.

Things That Affect Boring

• Drawers above doors. On base cabinets, the top hinge may need to sit lower so the plate clears the drawer slide or rail.
• Shelves. Keep hinge locations clear of fixed shelves on frameless cabinets, or the plate won’t mount.
• Narrow stiles. On glass or very narrow frame doors, the stile must be wide enough for a 35mm cup.
• Inset doors. Inset hinges may use a different boring distance. Tell us the hinge model.
• Thermal foil (RTF) and thin doors. Confirm the door thickness works with your hinge’s cup depth.

Matching the Hinge to the Boring

Boring prepares the door. The hinge and mounting plate determine overlay and fit. Before ordering, confirm:

• Cabinet type: face frame or frameless
• Overlay amount: for example 1/2" on face frame, or full overlay on frameless
• Opening angle: standard around 110°, wider for some applications
• Soft-close or standard

See Soft-Close Hinges: How to Pick the Right One for Your Door for more.

FAQ

Is hinge boring universal? The 35mm cup is standard across most concealed hinges. Edge distance and screw pattern vary slightly, so share your hinge model if you have one.

Can I bore doors myself? Yes, with a 35mm Forstner bit and a boring jig to control depth and edge distance. Practice on scrap first.

What if I don’t know where the plates are? Order with standard locations and install new plates to match.

Do drawer fronts need boring? No. Drawer fronts attach with screws through the drawer box.

Order Bored Doors

Our Cabinet Doors can be ordered bored for concealed hinges, made to size in 9 wood species and 64 thermal foil colors, with no minimum order. Matching hinges and plates are in Hardware/Parts. Email information@craftedcabinet.com with your hinge model or locations if you’re matching existing plates.