Home locks
Inches, millimeters and reference points: avoiding lock-order measurement errors
Use the units in the selected product's guide and label your measurements clearly. Avoid rounding a close measurement into a familiar standard size. If your tape shows both units, a photo of the measurement can help resolve ambiguity. The important distinction is also where you measured: hole centers, door thickness and trim edges describe different dimensions even when their numbers look similar.
A measurement needs a label to be useful
A number such as seventy can describe millimeters, an approximate size or an unrelated dimension in a product listing. Write the unit and the reference points with every measurement. Door thickness, backset and spacing between mounting centers are different quantities even when their values happen to be similar. Clear labels prevent a precise-looking note from being interpreted as the wrong installation requirement.
Stay with the product's own drawing
Use the units and measurement locations shown in the selected manufacturer's preparation guide. If you convert for convenience, preserve the original reading rather than replacing it with a rounded approximation. Do not assume a near-looking metric value is an exact substitute for a stated imperial requirement. Product compatibility depends on the actual specification and permitted tolerance, not on making the measurement resemble a familiar size.
Use photographs to expose uncertainty
A photograph of the tape or ruler in position can show whether the measurement began at the correct edge and crossed the intended center. Keep the image square enough to be useful and include context identifying the opening. If a trim plate hides the relevant point, record that limitation. It is better to ask for an installer measurement than to present an estimate from a decorative edge as a confirmed bore dimension.
Keep multiple doors from becoming one record
For several openings, assign each a simple identifier and keep its measurements together. Similar-looking doors can differ in thickness or previous preparation. Avoid copying one door's numbers across the whole property because the handles match. A short per-door record helps a Sacramento homeowner or property manager obtain a proposal that matches the actual openings rather than an assumed standard repeated through the building.
Resolve close readings before purchasing
When a measurement seems between supported sizes or conflicts with an earlier record, recheck the method and ask the installer to confirm it. Do not drill or order a nonreturnable component merely to keep the project moving. Schlage's official support resources can help locate the correct drawing for its products. A few clear measurements taken against the right references are more valuable than many unlabeled numbers gathered quickly.
Before you call
- Write units and reference points beside every dimension.
- Preserve original readings when making conversions.
- Resolve uncertain measurements before purchasing or modifying the door.
Follow-up questions
Should I round a measured dimension to the nearest common lock size?
Not to establish compatibility. Preserve the actual reading and check the product's requirements. An installer can assess whether the measurement or preparation needs further review.
Is one measurement sheet enough for several matching-looking doors?
Use a separate identified record for each opening. Appearance does not establish identical preparation, and copied assumptions can lead to ordering the wrong quantity of suitable hardware.
Official reference
Schlage: product support and FAQs ↗
Official product support. Identify your exact hardware before following installation or troubleshooting instructions.
Published by AID Locksmith, owned by Allan, serving Greater Sacramento. General service checklists are editorial guidance; product instructions apply to the named model.