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How to fit a cam lock without wrecking the door

Updated: 20.10.2026

The cupboard door is open, the old key is gone, and you have a drill. How to fit a cam lock is a short job if the hole matches, and a ruined face if it does not. Furnica puts a careful 19 mm fit at about 15–20 minutes. Check the numbers, drill so the laminate survives, set the nut and the cam, and stop if the door is shut. The [cabinet lock comparison](/hub/burglar-protection/cabinet-lock) is the product table. We did not drill a door for this guide. A qualifying purchase can earn a commission at no extra cost to you.

The cupboard door is open, the old key is gone, and you have a drill. How to fit a cam lock is a short job if the hole matches, and a ruined face if it does not. Furnica puts a careful 19 mm fit at about 15–20 minutes.

Our top picks

VOCIBO VOCIBO 16 mm letterbox cam lock, 4 keys

Best overall

VOCIBO VOCIBO 16 mm letterbox cam lock, 4 keys
8.8/10about £5.99
View offer
shinfly shinfly 16 mm cam lock with 5 plates

Best value

shinfly shinfly 16 mm cam lock with 5 plates
8.4/10about £5.49
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Mclcvp7re Mclcvp7re DUYIT07 22 mm cam lock, pack of 2

Alternative

Mclcvp7re Mclcvp7re DUYIT07 22 mm cam lock, pack of 2
7.0/10about £6.99
View offer
On this page
  1. 1.Check the door is open and the numbers match
  2. 2.Drill without tearing the face
  3. 3.Nut, clip and cam
  4. 4.When fitting has already gone wrong

Check the door is open and the numbers match

If the door is shut and the plug will not turn, stop. Drilling the cylinder first is how a cheap lock becomes a door you replace. Agree a locksmith’s quote. Advertised figures run from about £39 for cabinet labour and from £85 for a stuck key. They are not a tariff. Measure panel thickness, the existing hole, and body length from the back of the head to the end of the cylinder, cam excluded. The Mclcvp7re pair states 16 mm. The shinfly bullet says 18 mm; a review says the photos show 17 mm. The VOCIBO, Litensh and Lpraer state 19 mm. Drill the bullet, not a universal size. The shinfly note says the cylinder should sit about 5–6 mm longer than the case so a 4 mm hex nut can tighten. If the body is shorter than the panel, change the lock. Those measurements are on the cabinet lock buying guide.

Drill without tearing the face

Mark the centre on the inside and punch it. A twist bit tears veneer on the way out. A Forstner bit or a hole saw, from the inside into a backing board, cuts a cleaner disc. Masking tape on the show face reduces chip-out. A hole 1 mm small will not take the body. A shinfly buyer drilled 17 mm in fibreboard and then hammered the lock in, because the bit could not enlarge the hole. File flats for a double-D after the round hole. A loose hole lets the lock spin. The Mclcvp7re screws were too short for a kitchen door. Have two longer screws of the right gauge.
VOCIBO VOCIBO 16 mm letterbox cam lock, 4 keys

Testsieger

VOCIBO VOCIBO 16 mm letterbox cam lock, 4 keys
8.8/10about £5.99
View offer

Nut, clip and cam

Hold the head, cloth over the chrome, while you tighten the nut. Firm enough that the cylinder does not rotate. No torque figure is published for these die-cast bodies, and a split zinc head is how they die. Seat a snap ring, as on the Litensh, and try to pull the head out. shinfly clips were called flimsy, and one washer had to be cut down. If you are cutting a washer, you are compensating. Set the cam across the frame in the locked position, door open. A 90° cam and a 180° cam are different products. A VOCIBO square tail would not take a star-shaped cam, so use a plate from the box. If the door springs open, the cam is short or the body has rotated.

When fitting has already gone wrong

A plug that sticks in the first week is the lock, not your technique. Litensh reviews include a body that came apart and a plug stuck closed. Drilling the plug destroys it. Do not do that while post is still in a letterbox. Stop if the key is snapped in a shut door, the hole is oval, the cupboard holds controlled drugs or flammable liquids, or the building needs one master key.

Common questions

What size hole do I drill?
The size printed for that lock. In this set that is 16 mm for the Mclcvp7re pair, an 18 mm drill for the shinfly, and 19 mm for the VOCIBO, the Litensh and the Lpraer pair. There is no single cupboard-lock hole. If the bullet and the photo disagree, follow the bullet and test the body in a scrap piece first.
Forstner or a twist bit?
A Forstner bit or a hole saw, from the inside into a backing board, leaves a cleaner face on veneer. A twist bit is more likely to tear the laminate as it exits. On fibreboard, drilling undersize and then trying to open the hole is how a 17 mm mistake becomes a hammered-in lock.
How do I stop the laminate tearing?
Mask the show face, punch the centre, and drill from the inside against a clamped backing board, or meet in the middle from both sides. Hold the body while you tighten the nut so the flats do not spin and chew the edge you just cut.
Which way does the cam point when it is locked?
With the door open, set the cam so it lies across the frame in the locked position and swings clear when you unlock. Confirm 90° or 180° against the listing before you tighten the cam screw. Then shut the door and tug. If it does not hold, the cam is the wrong length or the body is rotating.
How tight should the nut be?
Firm enough that the head does not rotate, then test the key. These are small die-cast bodies, and no torque figure is published for them. Overtightening cracks them. A snap ring should sit in its groove and resist a straight pull.
The listing says 18 mm and the photo says 17 mm. Which do I trust?
Trust the fitting bullet, and try the body in an offcut. That clash is a stored shinfly review: 18 mm in the text, 17 mm read from the photos, and a fibreboard hole that was too tight to enlarge cleanly.

Related pages

Cabinet lock for a letterbox

Best cabinet lock

Cabinet lock

Cabinet lock buying guide: measure before you order

Keyed alike vs keyed different for cupboard door locks

Sources

Public UK sources used for measurement, keying and the legal limit. Listing prices, stars and review counts are from amazon.co.uk on 19 October 2026.

  1. Lockshop Direct — how to measure a cam lock (retrieved 19 October 2026)
  2. Lock & Key Centre — choosing cam locks, KD, KA and rotation (retrieved 19 October 2026)
  3. G Johns — keyed-alike cam locks for cabinet doors (retrieved 19 October 2026)
  4. BSI Knowledge — BS 3621:2017+A1:2024 scope, building doors (retrieved 19 October 2026)
  5. legislation.gov.uk — Misuse of Drugs (Safe Custody) Regulations 1973, Schedule 2 (retrieved 19 October 2026)
  6. HSE — flammable-liquid storage in workrooms (retrieved 19 October 2026)
  7. Intertek Inform — BS EN 16948:2017 child-resistant cupboard devices (retrieved 19 October 2026)
  8. Locktrader — cabinet and cam locks, nut-fix and snap-fix (retrieved 19 October 2026)