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Deadbolt or Mortise Lock: Which One Fits the Door

Product Knowledge · Published 2026-10-14

Buyers often ask which lock is better. The honest answer is that the door has already decided. A door with a single bore hole takes one family of bodies; a door with a mortise pocket takes another. Choosing by preference rather than by prep is how a container arrives that will not install.

Look at the door before the catalogue

Three things sort the decision: what hole already exists, how thick the door is, and whether the project can still be prepped differently.

Swipe the table sideways to see the full specification →

Single bore holeUsually a deadbolt or a handle-set body
Mortise pocket cut into the edgeA mortise lock with a matching body
No hole yetEither family works; the decision moves to the door material
Door thicknessMeasured in millimetres, not assumed from the door type

If the doors are not yet prepped, you have real freedom. If they are already prepped, the hole is a constraint and the lock has to suit it.

A single-bore door takes a deadbolt

A deadbolt replaces the existing thumb-turn. The bore and the backset already exist, so installation is a swap rather than a joinery job. For retrofit projects this is usually the fastest route to a smart lock across a whole building.

  • Reuses the existing bore and backset where the dimensions match
  • Fits apartment and rental retrofit, where doors are already hung
  • Fewer parts to handle on site than a full mortise set
  • The bolt throws into the existing strike, so the frame is untouched

The trade-off is that a deadbolt carries less of the door's mechanical load than a mortise body, and the panel sits on the face of the door rather than flush with the edge.

A mortise pocket takes a mortise lock

Where a mortise body already sits in the door edge, the smart lock has to match that body: the case size, the backset, the faceplate and the spindle position. The six body sizes we build are 5050, 5845, 6860, 7255, 8545 and 8560, and lock-only supply is available if you already hold body stock.

Swipe the table sideways to see the full specification →

Body sizeCase length by case height in millimetres
BacksetFrom the door edge to the centre of the spindle or keyhole
Centre-to-centreBetween the spindle and the keyhole or cylinder
HandingLeft or right, read from the hinge side

Mortise sets ship with a cut-out template so the installer can check the opening before drilling. That template is the least expensive insurance in the whole order.

When the hole does not match anything

Non-standard mortise lengths, unusual backsets and stainless bodies are normal orders rather than special cases. We engineer from your drawing and sample before the production run, so the run is not the test.

  • Send a photograph of the door edge with a ruler against it
  • Or send the body drawing, or the old body itself
  • We confirm the fit in writing before anything is produced
  • The first article is measured against the drawing before the batch continues

What the choice costs and how long it takes

Swipe the table sideways to see the full specification →

Deadbolt, standard bodyNo tooling; the shortest lead time
Mortise, standard body from the six sizesNo tooling; template supplied
Mortise, non-standard bodyTooling and a sample round before production
Sample lead time3-7 days from the confirmed specification
Bulk lead time20-35 days after sample or artwork approval

Tooling is quoted as a separate line rather than blended into a unit price, so you can see what the non-standard part actually costs.

Confirm it in writing before you order

Whichever family you choose, the four values that have to be written down are door thickness, body or bore type, backset and handing. Get those onto the quotation and the order stops being a gamble.

A photograph of the door edge with a ruler against it answers more than a specification sheet, because it shows the hole that already exists.

Buyer Questions

Three questions this guide usually raises.

On this topic

Can I use a deadbolt on a door that already has a mortise pocket?

Usually not without filling and re-boring the door, which is joinery work. If the pocket exists, match the body instead - it is cheaper and does not weaken the door.

What if I do not know which body I have?

Measure the case length and height in millimetres and photograph the door edge with a ruler against it. That is enough for us to identify the family.

Does a non-standard body always need tooling?

Not always. Some sizes can be built from existing tooling. Send the drawing and we will say which it is before quoting.

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