What is Backset?
The term backset refers to the distance from the edge of a door to the centre of the handle or spindle hole. This measurement ensures the latch is positioned correctly, allowing the handle to operate smoothly and the latch bolt to align properly with the strike plate.
In Engineering Hardware across New Zealand, understanding backset measurements is essential for fitting door latches accurately.
Why Backset Matters
- Comfort: Ensures the handle sits at a natural and convenient distance from the door edge.
- Functionality: Keeps the latch bolt aligned with the strike plate for smooth door operation.
- Safety: Prevents drilling too close to the edge, which could weaken the door structure.
- Appearance: Helps achieve a balanced and professional door layout.
Common Tubular Latch Backset Sizes
In New Zealand, tubular latches come in several standard backset sizes. Choosing the correct size depends on the door width and handle design.
- 57 mm to 60 mm: The most common size for interior doors, offering good hand clearance.
- 70 mm or larger: Used for wider or decorative doors where more clearance is preferred.
How to Measure Backset
Measuring backset is simple and ensures compatibility with existing hardware or new installations.
- Locate the edge of the door.
- Measure from this edge to the centre of the spindle or handle hole.
- The measurement obtained is your backset.
- Match the backset when replacing or selecting a new latch to ensure a proper fit.
Choosing the Right Backset
- Door thickness: For standard 35–40 mm doors, a 57–60 mm backset is typical.
- Handle type: Lever handles often work best with larger backsets for more hand space.
- Existing holes: Always check current measurements before replacing hardware.
- Design preference: A larger backset moves the handle further from the edge for visual balance.
Tips for Door Hardware Installation
- Check that the latch bolt bevel faces the strike plate to ensure smooth closing.
- Confirm the latch fits the door thickness before drilling or mortising.
- Ensure spindle size and latch type are compatible with your handle set.
Frequently Asked Questions
- Is backset the same as latch length? No, backset measures to the spindle centre, while latch length includes the latch body.
- Can I use a 70mm latch on a door drilled for 60 mm? Not without repositioning the hole—always match the existing backset.
- Does backset affect door strength? Yes, drilling too close to the edge on thin doors can weaken the structure.
