Guide to choosing the right lock: type, measurements, and handing (without compatibility errors)
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by Víctor Manuel Morales
5 min reading time
Choosing a lock is not a matter of brand, but of technical compatibility. When replacing locks on already installed doors, the most common errors occur due to not verifying the backset, the center distance, the handing, or the cylinder type.
This guide is intended for the maintenance of homes, communities, offices, storage rooms, and metal or aluminum carpentry, where the important thing is to replace without modifying existing rebates or perforations.
It is installed on the surface without the need for mortising. Widely used on existing doors where the inside of the leaf is not to be modified or as additional reinforcement.
Common backset measurements: 60 mm, 70 mm, and 100 mm. It is also essential to correctly choose the right or left handing.
3) How to tell if the door is right or left handed
Stand on the side where you see the hinges:
Hinges on the right → Right-handed
Hinges on the left → Left-handed
On reversible locks, the latch can be adjusted, but for rim locks, the handing is usually specific.
4) Choose according to the actual use of the door
Main door of a home or community
Reinforced lock
Security cylinder
Anti-drill protective escutcheon
Additional deadbolt if a double locking point is desired
Interior or passage doors
Simple latch or with key
Compatibility with existing handles
Non-intensive residential use
Community access with intercom
Typical voltage 12 V
Check opening direction
Verify faceplate type and plate dimensions
Furniture, mailboxes, and lockers
Measure body diameter
Check usable length
Choose appropriate key type
Display cases and glass doors
Typical thickness 4–6 mm
Sliding or hinged
Compatibility with fastening system
5) Common mistakes when changing a lock
Not measuring before disassembling.
Buying by appearance and not by measurements.
Confusing 60 mm with 70 mm backset.
Not checking the center distance on doors with a long escutcheon.
Choosing the wrong cylinder or unsuitable length.
Not checking the actual handing.
Not confirming voltage on electric locks.
Installing a basic model on a heavy-use door.
Not checking compatibility with the existing frame.
6) Technical checklist before buying
Type: mortise / rim / deadbolt / electric
Handing: right or left
Backset: exact measurement in mm
Center distance: if applicable
Faceplate: round or square
Cylinder: correct format and length
Use: residential or intensive
Regulations: if specific certification is required
7) Professional considerations in maintenance and intensive use
In the maintenance of communities, offices, or frequently transited accesses, the choice of lock must consider the number of daily opening cycles, the robustness of the internal mechanism, and compatibility with standard metal doors used in Spain.
In intensive use environments, a basic residential lock can significantly shorten its lifespan. In these cases, it is recommended to opt for reinforced mechanisms, more resistant cylinders, and protective escutcheons.
Most professional replacements are made on standard measurements already installed, so working with common replacement references facilitates direct replacement without modifications to the existing structure.
8) Technical criteria to avoid returns due to incompatibility
One of the most common issues in locksmith spare parts is returns due to dimensional incompatibility. Verifying the backset, center distance, and cylinder format before placing an order reduces errors and avoids installation delays.
At VicHome, locks and cylinders are grouped by format and actual measurement, facilitating the identification of compatible models in common technical replacements.
