Interior Door Hardware Preparation Before Factory Machining - Blog

Before a factory cuts lock holes or hinge recesses, confirm the exact hardware model and approve a dimensioned preparation drawing. "Standard lock hole" and "standard hinge" leave too many details unresolved for a bulk interior door order.

A lock may look correct in a product photograph yet require a different backset, fixing pattern or door thickness. A hinge with the correct overall size may still have the wrong corner radius or leaf thickness for the prepared recess.

Start with the hardware template

Ask the buyer or installer for the manufacturer's current installation template, model number and function. Identify who supplies the hardware and whether the factory can check a physical sample. A screenshot showing only the handle shape is not sufficient.

For familiar residential bored locks, Schlage's preparation guidance includes a 2-1/8 inch crossbore and backset options of 2-3/8 or 2-3/4 inches. These are useful examples for the covered hardware, not dimensions to apply automatically to mortise locks, concealed hardware or every destination market.

Confirm the lock preparation as separate dimensions

Field	Why it matters
Crossbore	The face-hole diameter must suit the selected lock
Backset	Positions the lock center relative to the door edge
Edge bore or mortise	Receives the latch or lock case
Faceplate recess	Must match the plate size, corners and thickness
Lock height	Needs an agreed datum and centerline definition
Strike preparation	Must correspond to the latch and installed frame

State whether lock height is measured from the bottom of the leaf or the finished floor. These are different references when the installation includes a bottom clearance. If an edge is beveled, show the relevant measurement face in the drawing.

Match the complete hinge geometry

Record the hinge manufacturer, model, open size, leaf thickness, corner shape, screw pattern and required recess depth. Dimension hinge positions from a common datum, preferably without a chain of rounded conversions. State whether positions refer to the top of each hinge, its center or another template reference.

Do not set recess depth simply because another order used the same value. A recess that does not match the hinge leaf and installation requirements can affect clearances. Concealed hinges require their own pocket geometry and door or jamb thickness checks.

The hinge quantity and load capacity should suit the actual leaf weight, dimensions and usage. Keep this selection tied to the hinge manufacturer's requirements rather than assigning one hinge count to every hollow and solid core door.

Check reinforcement before approving holes

Identify the location and extent of the lock blocks and hinge fixing material. Larger mortise pockets, surface closers or special fixing patterns may require construction changes before pressing and finishing. A new hole location can fall outside the intended fixing area even if it fits on the visible face.
For a Shaker design, also check that the handle trim and fixing points fit the available flat area. Panel layout and internal reinforcement are separate checks; neither should be inferred from the other.

Prove the preparation with a first article

Use a representative leaf and matching frame to trial the actual hardware. Confirm that screws seat correctly, the leaf moves freely, the latch engages and the intended function works from both sides. Record the sample, template revision and approved machining drawing together.

Release repeat production against that record. If the buyer changes a hardware model later, review the preparation again even when the replacement looks similar.

Common buyer questions

Can I order doors now and select locks later

You can discuss an unmachined supply option, but avoid releasing lock preparation until the hardware is selected and the required reinforcement is confirmed.