How to Choose the Right Door Lock: Handle Lock vs Mortise Lock vs Rim Lock

Why the lock type matters

Not every door needs the same kind of lock. The right choice depends on the door material, how the lock is fitted, and how much security you need. The three most common types you'll find in a hardware shop are the handle lock, the mortise lock, and the rim lock - and mixing them up is one of the most common buying mistakes. This guide walks through how each one works, where it fits best, and what to check before you buy.

Handle lock (also called a cylindrical lock)

A handle lock combines a lever handle and a locking mechanism in one unit, fitted through two holes bored into the door - a larger one through the face for the lock body, and a smaller one through the edge for the latch. In hardware trade terms outside South Asia this same fitting is usually called a cylindrical lock, so if you're comparing products online under that name, it's the same thing as a handle lock.

• Good for: bedrooms, offices, internal doors, and many main doors
• Fitting: bored straight through the door face - no chiselling needed
• Typical strength: standard to main-door duty, depending on the model
• Note: because the latch and any deadbolt function are usually separate parts of the same unit, ask whether the model you're buying includes a proper deadbolt throw, not just a spring latch, if it's going on an entrance door

Mortise lock

A mortise lock sits inside a pocket (a "mortise") cut into the edge of the door, rather than through the face. It's usually paired with a separate handle or lever on the outside. Because the entire mechanism - latch, deadbolt, and springs - is housed in one solid metal case recessed into the door itself, mortise locks tend to feel heavier and more solid to operate, and they're harder to force open than a lock with separate latch and deadbolt units.

• Good for: main entrance doors, doors that need extra security, wooden doors thick enough to take a mortise pocket
• Fitting: recessed into the door edge - needs more precise carpentry than a handle lock, and the door needs enough thickness to take the lock body without weakening it
• Typical strength: generally higher-duty than a basic handle lock, since the whole mechanism is a single reinforced case

Rim lock

A rim lock is mounted on the surface of the door rather than cut into it, usually on the inside face, and is paired with a rim cylinder or knob on the outside. It's a practical option when you don't want to (or can't) cut into the door itself - useful on thin doors, added security on an existing door, or as a second lock alongside a handle or mortise lock.

• Good for: wooden doors where you want to avoid mortising, added or secondary locks, thinner doors that can't take a mortise pocket
• Fitting: surface-mounted, no deep cutting required - just screws and a hole for the cylinder spindle
• Typical strength: varies by model; many rim locks deadlock (the bolt can't be forced back once thrown), which makes them a genuinely useful second layer rather than just a backup

How "duty rating" works

Locks aren't all built to the same strength, even when they look similar. Hardware is generally sold as light duty (interior doors, low traffic), medium duty (bedrooms, offices, secondary doors), or main-door / heavy duty (entrances, doors facing the street). The difference usually comes down to the thickness of the metal in the latch and bolt, the quality of the springs, and how well the mechanism resists being forced or picked. There's no harm asking the shop directly which duty level a lock is rated for - a lock that looks similar to another can be built to a very different standard inside, and it's not something you can tell just by looking at the outside.

Quick comparison

• Simplest to fit: rim lock (no mortising) or handle lock (bored, not recessed)
• Most integrated and solid feel: mortise lock (fully recessed, single case, nothing visible on the door face)
• Best for a second layer of security: rim lock added alongside an existing handle or mortise lock
• Best all-rounder for most homes: a handle lock (cylindrical lock) rated for main-door duty, often paired with a mortise deadbolt on the front entrance

Buying tips

• Measure the backset - the distance from the door edge to the centre of the handle or cylinder - before you buy. Sizes vary between models, and a mismatched backset means the lock won't sit right.
• Check the door thickness. Mortise locks in particular need enough timber depth to take the lock body without weakening the door.
• Confirm the handing (left or right opening) if the model needs it - most modern handle locks are reversible, but some mortise and rim locks aren't.
• Ask about the finish. In Karachi's humid, coastal air, brass and stainless finishes hold up noticeably better over time than plain plated steel, which can start showing surface corrosion within a couple of humid seasons if it isn't wiped down and lightly oiled occasionally.

Common questions

Can I replace a handle lock with a mortise lock later?

Usually yes, but it means cutting a new mortise pocket into the door edge, which is more carpentry work than swapping one handle lock for another. If you're renovating and might want the extra security of a mortise lock eventually, it's worth deciding before the door is hung or painted.

Do I need a separate deadbolt if I already have a handle lock?

If the handle lock's only locking action is a spring latch (no separate deadbolt throw), a lot of homeowners add a mortise deadbolt or a second rim lock above it for a main entrance door, since a spring latch alone is easier to force than a proper deadbolt.

How often should I oil a lock?

A light machine oil or graphite lubricant on the latch and keyway every few months keeps the action smooth, especially in humid weather - avoid thick grease, which attracts dust and can gum up the mechanism over time.