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How to fit a nightlatch on sound timber, step by step

Updated: October 2026

How to fit a nightlatch comes down to the hole already in the door. The distance from the edge to the keyhole is the backset, and the other size means new drilling. This is the sequence for a surface latch on sound timber, not a ranking. The products sit on the [door lock comparison](/hub/door-and-window-security/door-lock). The Yale 77 is the top pick and the lowest price, so there is no separate best-value badge. Peter F. used the fitting sheet, trade guides and amazon.co.uk reviews in October 2026. No lock was fitted for this page. A qualifying purchase can earn a commission at no extra cost to you.

How to fit a nightlatch comes down to the hole already in the door. The distance from the edge to the keyhole is the backset, and the other size means new drilling.

Our top picks

Yale Yale 77 nightlatch

Best overall

Yale Yale 77 nightlatch
9.2/10about £11.64
View offer
Nuki Nuki Smart Lock Ultra

Rank 2

Nuki Nuki Smart Lock Ultra
9.0/10about £309
View offer
QWORK QWORK antique night latch

Rank 3

QWORK QWORK antique night latch
8.2/10about £11.99
View offer
On this page
  1. 1.Measure before you drill
  2. 2.Fitting a 60 mm nightlatch on timber
  3. 3.What the Yale 77 reviews show after fitting
  4. 4.Stop and call a locksmith

Measure before you drill

Backset is the distance from the door edge to the centre of the keyhole, not to the edge of the case. Both 40 mm and 60 mm nightlatches are sold in the UK, and they are not interchangeable. locksmiths.co.uk calls 60 mm usual, so measure your door. The Yale 77 at about £11.64 is the 60 mm version. The QWORK states a 32 mm hole and doors of 35–64 mm, and no backset. On a door under 45 mm, Yale's P-77 sheet says shorten the connecting screws. The amazon warranty is 12 months. A separate PDF footer says 10 years, which is not the guarantee on the box. A fire door is specified separately.

Fitting a 60 mm nightlatch on timber

If the hole is 60 mm to its centre and the timber is sound, you are replacing like for like. Yale's sheet uses a 32 mm hole. Drill from both sides so the face does not blow out. The case screws to the inside. The cylinder comes through from the outside, and the connecting screws draw the halves together. Shorten those screws under 45 mm or the case will not sit flat. Cut the spindle tail so the latch throws without jamming. Chisel the frame so the door meets the staple. If you must lift the door to latch it, the staple is wrong. If it only catches on a slam, reset the staple. The buying guide decides whether a nightlatch was the right family.
Yale Yale 77 nightlatch

Testsieger

Yale Yale 77 nightlatch
9.2/10about £11.64
View offer

What the Yale 77 reviews show after fitting

The file, 4.6 from 3,166 amazon.co.uk ratings, is mostly swaps of an older nightlatch. Only two keys are in the box, and reviewers pay to cut more. Test a spare before you throw the old keys away. Screws are often missing. The metal is described as lighter than an older Yale or Union. A snib that will not move has been enough for a return, which is a lock fault, not a bad hole. One case sat slightly taller, so the fitter cut a shallow groove. Check the paint scar before you drill extra holes. Both keys must throw, the snib must move with a thumb, and the door must latch without a slam. Leave the snib free if someone is still outside.

Stop and call a locksmith

This sequence stops at a surface latch on sound timber. A mortice cut is not described here. A uPVC face is the wrong place for a 32 mm rim hole, because those doors lock through a multipoint strip. The Nuki replaces a euro cylinder and does not use this drilling. Glass, a rotten stile, a crumbling frame, a fire door, and a move where you do not know who still has keys are stop points. The Master Locksmiths Association at locksmiths.co.uk lists locksmiths for that work.

Common questions

How do I measure the backset?
Open the door and measure from the edge of the door to the centre of the keyhole, in millimetres. That centre distance is the backset. A case that looks about the same can still be 40 mm when you needed 60 mm. Write the number down before you order. The Yale 77 in this comparison is 60 mm. The QWORK listing does not state a backset at all.
Is my door 40 mm or 60 mm?
It is whichever figure you just measured. Both sizes are sold in the UK. A local fitter may see mostly 40 mm, while a locksmith guide may call 60 mm usual. Neither sentence measures your door. If the hole is 40 mm, the 60 mm Yale 77 will not line up without a new hole.
What size hole does a Yale nightlatch need?
Yale’s fitting sheet for the 60 mm P-77, and the Lock Shop Warehouse rim-latch guide, both use a 32 mm hole for the cylinder. Drill from both sides so the face does not break out. The QWORK listing also states a 32 mm hole, for doors 35–64 mm thick, which is the hole size and not a backset.
Can I reuse the old holes?
Yes, when the new lock is the same backset and the old screw holes still bite in sound timber. That is the swap reviewers describe, often in a few minutes. Check the new case against the old paint mark first. One Yale 77 sat slightly taller, so a shallow groove was needed. If the holes are in a crumbling stile, reuse is how the lock pulls off.
What if the screws are missing?
Several Yale 77 reviews say the screws were not in the box, so the lock could not go on that day. Buy screws that match the old ones, rather than forcing screws that come through the face. On a door under 45 mm the connecting screws are shortened so the case sits flat. The amazon warranty on this listing is 12 months, not the 10-year footer on a separate PDF.
When do I stop and call a locksmith?
Stop for a new mortice, glass, a rotten frame, a fire door, a uPVC door, or keys that someone else may still hold after a move. A like-for-like 60 mm swap on sound timber is the job this page describes. locksmiths.co.uk lists members for the rest. The Nuki is a euro-cylinder motor, not a reason to drill a rim hole.

Related pages

Nightlatch or mortice

Best door lock

Door lock

What door lock do I need for the door in front of you

BS 3621 door lock insurance: what the schedule asks

Sources

Public UK and manufacturer sources from the research digest, used for this page in October 2026. Prices, stars and review counts are the amazon.co.uk figures in this comparison. None of the four locks is treated as BS 3621, TS007 or Sold Secure.

  1. AA Insurance: door locks (retrieved October 2026)
  2. AXA LC01 locks requirement (retrieved October 2026)
  3. police.uk: door and window lock advice (retrieved October 2026)
  4. ProtectUK: security at home (retrieved October 2026)
  5. West Yorkshire Police: burglary advice (retrieved October 2026)
  6. Allianz: house locks (retrieved October 2026)
  7. Financial Ombudsman DRN-5526434 (retrieved October 2026)
  8. Yale BS1 nightlatch (retrieved October 2026)
  9. Master Locksmiths Association (retrieved October 2026)
  10. Nightlatch measuring guide (retrieved October 2026)